Search

The cellular Ti(C,N)-based cermets were prepared by multiphase flow agglomeration and subsequent vacuum sintering. By precisely controlling the vacuum degree and temperature, the fine particles collided and then agglomerated together through the surface tension of bubbles generated by the dissolved gas in the slurry, forming a multiphase flow with the liquid medium as the slurry dried. Subsequently, the dried powder mixture containing the agglomerates was subjected to pressing and vacuum sintering to obtain cellular cermets. The cellular cermets were analyzed using DSC, XRD, SEM, TEM, and EDS. During the solid-phase sintering stage, the agglomerates were relatively loose and easily to be destroyed, showing large gaps with the matrix, while the gaps gradually decreased and the density slightly increased as the temperature increased. During liquid phase sintering, the grains in agglomerates were further dissolved to gain fully fine-grained agglomerates, and the interface between the agglomerates and the matrix became clear. Finally, a dense sintered body with cellular structure in which agglomerates were dispersed in the matrix was formed. Furthermore, agglomerates were mainly composed of grains with black core-gray rim and grains without obvious core/rim structure, forming distinct interfaces with the coarse-grained matrix. The cellular Ti(C,N)-based cermets exhibited superb mechanical properties, with TRS of 2184 ± 30 MPa, fracture toughness of 9.01 ± 0.3 MPa m1/2, and hardness of 93.4 ± 0.2 HRA, making them superior to traditional Ti(C,N)-based cermets. [ABSTRACT FROM AUTHOR]

In this study, based on different element configurations within constant atomic ratio of elements, (Ti 0.93 W 0.07 Mo 0.07)C–20%Ni and (Ti 0.93 W 0.07 Mo 0.07)CN 0.3 -20%Ni derived cermets have been synthesized. The basis for the difference in the production route was whether the carbides were formed by carbothermic reaction from the metal oxide together or separately, or in the case of Mo 2 C, the carbide is added to the mixture together with the binder after reduction and just before consolidation. Another basis for the difference was whether the cermet was a carbide or a carbonitride. To investigate the influence of the different production routes, the crystal structure, microstructure, and mechanical properties of the cermets produced were examined using XRD, FESEM, STEM, and Vickers indentation. The XRD spectra of all the cermets were found to be very similar to those of TiC-based cermets, indicating that the additive carbides in the TiC or Ti(CN) phases of the cermets dissolve perfectly during the high vacuum sintering process at 1510 °C. The highest toughness (14.65 MPa m1/2) was obtained in (Ti 0.93 W 0.07) C–8%Mo 2 C–20Ni cermets with a core-rim structure. In addition, the use of nitrogen leads to a dramatic reduction in particle size. The use of molybdenum and tungsten in the form of separate carbides had little effect on limiting the expansion of crystal size and grain size compared to the scenario where the dissolution of these elements took place within the primary core-rim structure. However, in terms of hardness and toughness, it was found that, in addition to grain size, the route taken in the addition of molybdenum and tungsten was also important. [ABSTRACT FROM AUTHOR]

MoCoB–Co cermets with varying carbon contents were synthesised using reactive boronizing sintering, followed by an investigation into their microstructure and mechanical properties. Adding an appropriate amount of carbon facilitates the wetting of liquid on ceramic particles and improves the density of the cermets. However, excessive carbon addition can render some carbon insoluble, leading to a reduction in density. With the increase in carbon content, the pores transition from spherical to irregular shapes, and the MoCoB particles shift from equiaxed to long rod-like structures. The presence of long rod-like MoCoB particles promotes crack deflection and transgranular fracture, thereby improving the toughness of the material. The bonding strength of the MoCoB/hcp-Co interface is higher than that of the MoCoB/fcc-Co interface. Carbon addition increases the hcp-Co content in the binder phase, further improving the toughness of the material. Cermets with a 0.5 wt% carbon additive exhibit outstanding mechanical properties, including a hardness, transverse rupture strength and fracture toughness of HRA 91.5, 1967 MPa and 15.3 MPa m1/2, respectively. [ABSTRACT FROM AUTHOR]

The microstructure and reactivity of Ni-GDC cermet under cyclic oxidation in CO 2 conditions were investigated using temperature-programmed reduction (TPR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The XRD results revealed that NiO was formed during the re-oxidation process in CO 2. SEM and TPR results demonstrated that nanostructured NiO aggregates were formed on the surface of the sample after being re-oxidized at 400 °C for 1200 min, resulting in an α peak with high reduction activity and a conversion of only 16% from Ni to NiO. In contrast, the samples re-oxidized at 600 °C for 600 min and 800 °C for 240 min were completely oxidized, resulting in reconstructed and sintered NiO with larger particle size, and a β peak with lower reactivity and a conversion of 100%. Redox cycling was further conducted on completely oxidized samples, which showed a decrease in β peak temperature from the first to seventh cycle. The migration and redistribution of sintered NiO towards the exterior were confirmed by comparing SEM images after the first and fourth cycles, which favored an increase in the reactive area. Therefore, this study reveals that lower re-oxidation temperatures (≤400 °C) and an appropriate increase in redox cycles are beneficial for forming surficial nanostructures while hindering the formation of large sintered NiO particles. [Display omitted] • Low oxidation temp range favors surface nanoparticles for NiO-GDC in CO 2. • High re-oxidation temp ranges can promote the migration and growth of NiO. • Long re-oxidation time in CO 2 can cause the bulk reconstruction and sintering. • Redox cycle favors sintered large NiO re-dispersive to improve reduction activity. [ABSTRACT FROM AUTHOR]

Aluminum dross (AD) and red mud (RM) are waste discharged from aluminum industry. AD and RM contain 5-15 wt% of hazardous aluminum nitride (AlN) and 20–50 wt% of iron oxide, respectively. In this work, alumina-based cermet was in-situ prepared from AD and RM, after reduction of iron oxide with AlN by pyrometallurgy. Cermet was consisted of metal reinforcement phase about 1 μm, alumina matrix phase and low-melting aluminosilicate binder. Mechanism of in-situ preparation was studied after exploring phase composition of the cermet powder. Iron, silicon and titanium oxide from RM was reduced into Fe 3 Si and TiN, which acted metal reinforcement phase in cermet. Reaction was consisted of two steps, Fe 2 O 3 , TiO 2 and AlN dissolving into low-melting aluminosilicate and electron transferring from AlN to Fe 2 O 3 , SiO 2 and TiO 2. Content of Fe in ceramic phase was decreased from 6 at.% to 1 at.% after reduction reaction. Low-melting aluminosilicate acted both reaction solvent for reduction reaction, and binder for metal reinforcement phase and alumina matrix phase. More low-melting aluminosilicate was formed when temperature was increased from 1200 °C to 1400 °C, which made more metal balls be formed. The metal ball and alumina were bonded by low-melting aluminosilicate, which increased the bond strength between reinforcement phase and ceramic phase in cermet. This work achieved a total recycle of AD and RM into cermet. It was proposed a novel idea of in-situ preparing cermet, which was generating metal reinforcement phase in ceramic matrix phase. [Display omitted] [ABSTRACT FROM AUTHOR]

The TiB 2 -TiN-HEA cermet materials were synthesized in-situ reaction hot-pressing sintering at 1450 °C for 1 h, utilizing Ti, BN, and Al 0.3 CoCrFeNi high entropy alloys (HEA) as starting materials. The thermodynamic characteristics of the reaction system and the phase structure, microstructure, and mechanical properties of Ti-BN, Ti-HEA, BN-HEA, and Ti-BN-HEA were investigated. The results demonstrate that in-situ reaction hot pressing sintering phases include TiN, TiB 2 , and FCC structural. The synthesis of TiB 2 involves the diffusion of B to TiB and the subsequent combination of Ti and B in solution. Conversely, the formation of TiN consists of the diffusion of N to TiN 0.3 and Ti 2 N, as well as the subsequent combination of Ti and N in solution. The TiB 2 -TiN-HEA cermet exhibits a relative density of 99.1%, Vickers hardness of 18.91 GPa, flexural strength of 721 MPa, and fracture toughness of 7.61 MPa m1/2. The high strength of cermet was due to a combination of factors, including the synergistic effect of high compactness of composites, reinforced interfacial strength with HEA, reinforcement of fine-grains and TiB 2 rod-like grains, crack bridging and deflection, and transgranular fracture. [ABSTRACT FROM AUTHOR]

The heavy transition metal borides, carbides, and nitrides are still difficult to synthesize, and certain compositions are not even possible to stabilize. With the help of existing materials databases, we assemble 240 materials of chemical formula M 2 X, that we intend to investigate via density-functional theory (DFT). Our calculations demonstrate the stability of several novel compounds, which are highly likely to be synthesized in experiment, widening the potential applications as structural ceramics. The X site plays the primary role in determining the structural stability, with boron leading to many more stable ceramics than carbon and nitrogen. The chemical bonding is found to arise from a mixture of covalent bonding (M-X) and weak metallic bonding (M-M), which ensures varied elastic properties. Among the newly predicted materials, Tc 2 B ,Os 2 B , and Os 2 C are shown to be ultra-incompressible. A low shear modulus makes these systems prone to plasticity, which leads to an interesting coexistence of hardness and ductility for novel Os 2 B and Os 2 C , as well as existing Mo 2 B and Mo 2 C. Chemically, replacing 4 d with 5 d elements is shown to enhance bulk and shear moduli, which could be used for hardness engineering by selective doping. This report lays the foundations for further experimental research on the mechanical merits of the late transition metal borides, carbides, and nitrides of chemical formula M 2 X. [ABSTRACT FROM AUTHOR]

316LSS is used in various industrial applications, including heat exchangers, dyeing equipment, pulp and paper equipment, and marine equipment for chemicals, dyes, paper, oxalic acid, fertilizer, etc. Corrosion has always been the most serious problem across these applications. For this reason, this research specifies the features of 316LSS, the use of inhibitors for control, austenitic 316LSS research with inhibitor efficiency, the environment employed, its concentration, experimental analysis, and an emphasis on organic inhibitors for a sustainable industry. Applying thermally stable HVOF WC-10Co-4Cr powder coatings over the 316LSS can reduce this impact. The current study examines the effects of HVOF cermets powder coatings on the assessment of the 316L SS microstructure, oxidation, and corrosion behavior in a hostile situation of Na2SO4-88%Fe2 (SO4)3 at 800 °C for up to 50 times. Every cycle lasted one hour at 800 °C for heating and twenty minutes at ambient temperature for cooling. The thermogravimetric method was used to study the hot corrosion kinetics, and it was discovered that these abide by the parabolic rate rule. The analysis of the results identified that the HVOF 86WC-10Co-4Cr sprayed coating on 316LSS has shown excellent oxidation and resistance to corrosion as compared to uncoated base metal and good coating adherence to the substrate under the tested environment. [ABSTRACT FROM AUTHOR]

Development of high-performance cutting tool materials is one of the critical parameters enhancing the surface finishing of high-speed machined products. Ti(C,N)-based cermets reinforced with and without different contents of silicon nitride were designed and evaluated to satisfy the requirements. In fact, the effect of silicon nitride addition to Ti(C,N)-based cermet remains unclear. The purpose of this study is to investigate the influence of Si3N4 additive on microstructure, mechanical properties, and thermal stability of Ti(C,N)-based cermet cutting tools. In the present work, α -Si3N4 "grade SN-E10" was utilized with various fractions up to 6 wt.% in the designed cermets. A two-step reactive sintering process under vacuum was carried out for the green compact of Ti(C,N)-based cermet samples. The samples with 4 wt.% Si3N4 have an apparent solid density of about 6.75 g/cm3 (relative density of about 98 %); however, the cermet samples with 2 wt.% Si3N4 exhibit a superior fracture toughness of 10.82 MP a.m 1 / 2 and a traverse rupture strength of 1425.8 MPa. With an increase in the contents of Si3N4, the Vickers hardness and fracture toughness of Ti(C,N)-based cermets have an inverse behavior trend. The influence of Si3N4 addition on thermal stability is clarified to better understand the relationship between thermal stability and mechanical properties of Ti(C,N)-based cermets. [ABSTRACT FROM AUTHOR]

Purpose: Total hip arthroplasty (THA) in younger patients remains controversial due to concerns regarding long-term implant survival and potential complications. This study aimed to evaluate long-term clinical outcomes, complications, differences in complication and revision rates by bearing surfaces, and Kaplan–Meier survival curves for THA in patients under 20 years old. Methods: A retrospective review was conducted for 65 patients (78 hips) who underwent THA between 1991 and 2018. Their mean age was 18.9 years. Their clinical outcomes were assessed using the Harris Hip Score (HHS). Radiological outcomes were evaluated based on the presence of loosening, osteolysis, and heterotopic ossification. Complications such as dislocation, periprosthetic fractures, and infections were assessed. The mean follow-up period was 13.2 years (range, 5.0–31.2 years). Results: The mean HHS improved from 44.6 to 90.1. There were two cases of dislocation. However, no periprosthetic fracture, deep infection, or ceramic component fracture was noted. There were 19 revisions of implants. Eighteen of 19 hips were operated with hard-on-soft bearings in the index surgery (p < 0.01). The 23-year survivorship was 97.8% for THA using ceramic-on-ceramic bearings, while the 31-year survivorship was 36.7% using hard-on-soft bearings. Conclusion: THA in patients under 20 years old yielded promising clinical and radiological outcomes, although polyethylene-bearing-related concerns persisted. Previously operated patients with hard-on-soft bearing should be meticulously examined during the follow-up. As ceramic-on-ceramic bearing showed excellent survivorship in this particular cohort, we recommend the use of this articulation as the bearing of choice. [ABSTRACT FROM AUTHOR]

Computer-aided design (CAD) models can now be directly converted into products and structures. One technique to realize such approach is through Additive Manufacturing (AM). AM is relatively new manufacturing technology in which products are manufactured by layering various materials like rubber, metal, ceramic, composites, and polymers. However, the use of this technology requires consideration of its associated cost to ensure its competitiveness. In this paper, a simplified mathematical cost model is suggested. The model considers the main components of costs. The model formula utilizes expenses related to the pre-processing, main processing, and the post-processing operations. To validate the model, it is tested to estimate the cost of medical implants manufacturing using AM technique. In many cases, medical implants require unique or dedicated design for each patient. Hence cost estimation will help to assess and estimate the required financial resources for such operations. A case study is provided in this paper to estimate the manufacturing cost of a finger's phalanges bone, with metal implant using AM technique. The developed model may be described as Activity Based Costing (ABC). The model is introduced to estimate the cost of parts produced using AM technique. Although the model is developed to suit custom implant manufacturing using AM technique, its use may also be adapted to suit the manufacturing of many other parts and products. The developed model is aiming to achieve several tasks namely assigning cost drivers to each activity, estimating the cost of individual actions, allocating overhead expenses, calculating the overall production cost, and establishing an acceptable selling price. It assists companies in computing the cost of custom implants for customers, enhancing the accuracy of production cost estimates, and ultimately boosting profitability. [ABSTRACT FROM AUTHOR]

Combining with the advantages from mature technologies of fused deposition modelling and powder injection molding, 3D NiFe 2 O 4 -based cermet with weight over 1.3 kg and relative density of 95.8 % were fabricated by composite extrusion modelling using polyoxymethylene-based feedstock. Microstructure and rheological properties of the feedstock, roles of printing parameters on the morphology green samples and related catalytic debinding, sintering properties of cermets were investigated in detail. Uniformly dispersed cermet powders in feedstock were confirmed, due to the good wettability between the powders and binders. The feedstock with high solid loading of 58 vol% exhibited shear-thinning behavior and contained high storage modulus for reliable shape retention. With optimized printing parameters, a high compression ratio (layer height/nozzle diameter) over 2.5 tended to shrink the size of stacking pores, resulting in dense green samples. Catalytic debinding was proved to be defect-free and efficient debinding route, which was successfully used to deal with dense cubic samples with thickness of 30 mm. Sintered samples showed uniform microstructure with interconnected FeCuNi and Ni(Fe)Fe 2 O 4 phases. Except for partial stacking pores in the fracture section, polished cermets exhibited mirror-like surfaces, indicating the good controlling of the final microstructure and performance of 3D cermets. [ABSTRACT FROM AUTHOR]

A novel method was proposed to prepare Ti(C,N)-based cermets with a cellular structure by controlling the drying conditions and subsequent vacuum sintering, the as-prepared cermets combine the advantages of fine grains with those of coarse grains, and show superior mechanical properties compared to conventional cermets. The microstructure, interface characteristics and mechanical properties of cellular cermets were systematically investigated. The SEM analysis revealed that cellular cermets comprised fine-grained aggregates and coarse-grained matrix; these aggregates were distributed in the matrix, which formed obvious interfaces between them. With increasing drying temperature and decreasing drying gas pressure, the volume fraction of aggregates in vacuum-sintered cermets first increased and then decreased. In addition, semi-coherent and coherent relationships were formed at the ceramic/binder phase boundaries in the aggregates and matrix, respectively, leading to the improvement of toughness. By optimizing the drying conditions, significant grain refinement was observed in the cellular cermets; these cermets exhibited excellent mechanical properties, i.e., hardness of 93.2 ± 0.1 HRA, transverse rupture strength of 2030 ± 32 MPa, and fracture toughness of 8.8 ± 0.1 MPa m1/2. The refinement of ceramic grains was found to be the dominant factor responsible for the increased hardness and strength, while the improvement of toughness was mainly due to the unique characteristics of the aggregates and matrix. [ABSTRACT FROM AUTHOR]

In this paper, by adding Co, Mo, and Ni metal binder and using spark plasma coupling high-frequency induction (SP–HF) sintering technology, high-entropy (W,Nb,Mo,Ta,Ti)C cermet with good performance was successfully prepared at 1350 °C. The sintering temperature was much lower than that of the solid-state sintering temperature adopted for high-entropy carbide ceramics (about 2000 °C) while maintaining high hardness and fracture toughness. The effects of sintering temperature, holding time and sintering pressure on the mechanical properties of high-entropy (W,Nb,Mo,Ta,Ti)C cermet were investigated. The experimental results show that the SP-HF sintering can promote the liquid phase flow inside the high-entropy (W,Nb,Mo,Ta,Ti)C cermet and improve the density. The high-frequency induction sintering effect of the high-intensity magnetic metal binder phase (Co, Ni) promotes the rapid diffusion of the constituent phases using the vacancy mechanism and the metal liquid phase, which helps to form a high-entropy cermet solid solution at a lower temperature. The different high-entropy effects of the inner and outer layers of high-entropy (W,Nb,Mo,Ta,Ti)C cermet materials play a role in strengthening and toughening the materials, and effective solid solution strengthening is the main reason for improving mechanical properties. The mechanical properties of high-entropy (W,Nb,Mo,Ta,Ti)C cermet are the optimized at 1350 °C, holding time of 8 min, and sintering pressure of 35 MPa. The Vickers hardness, fracture toughness, and flexural strength are 18.38 ± 0.19 GPa, 9.65 ± 0.25 MPa · m1/2 and 970 ± 30 MPa, Vickers hardness was measured at 49 N load. [ABSTRACT FROM AUTHOR]

Carbon‐free aluminum electrolysis is crucial for achieving the low‐carbon development and carbon neutrality in the future aluminum industry. NiFe2O4‐based cermet is the potential candidate of inert anode, benefiting from the satisfactory corrosion resistance and high‐temperature conductivity. Herein, complex‐shaped 25(Cu–20Ni)/(NiFe2O4–10NiO) cermets were fabricated via a plastic shaping method using the polyformaldehyde (POM)‐based granular feedstock. The feedstock showed uniform microstructure with evenly dispersed powders wrapped in polymers, which exhibited shear‐thinning behavior during molding. Roles of the feedstock with different powder loadings in the morphology and bending strength of the cermets were investigated. High‐precision gear parts exhibited no deformation, a high relative density over 98%. Investigation of different powder loadings revealed that parts prepared with a 56 vol% loading demonstrate the excellent performance, and possessed an impressive flexural strength of 178.4 MPa. This achievement provided a foundation for the future utilization of complex‐shaped inert anode material components in industrial applications. [ABSTRACT FROM AUTHOR]

(HfNbTaZrTiMo)C‐Co high entropy carbide cermet was fabricated by conventional vacuum sintering. The effect of WC addition on the mechanical properties of cermets was also investigated. For cermets without WC addition, with the extension of sintering time, the hardness of cermets first rose and then fell, while the fracture toughness showed a decreasing trend. The increase in sintering temperature led to a decline in hardness and an enhancement of fracture toughness. The (HfNbTaZrTiMo)C‐15 wt. % Co cermet sintered at 1450°C for 2 h had the best comprehensive properties, with the hardness and fracture toughness of 16.36 ± 0.17 GPa and 7.19 MPa·m1/2, respectively. After adding WC, there was a typical black core (undissolved (HfNbTaZrTiMo)C phase)‐gray rim (seven‐component (HfNbTaZrTiMoW)C solid solutions) structure in the cermets. Meanwhile, Mo diffused into WC to form (Mo, W)C solid solutions. The formations of (HfTaZrNbMoTiW)C and (Mo, W)C solid solutions resulted in an improvement in hardness. In addition, since the addition of WC enhanced the wettability between carbides phase and Co phase, the comprehensive properties of cermets were improved. The hardness and fracture toughness of the (HfNbTaZrTiMo)C‐42.5 wt. % WC‐15 wt.% Co cermet sintered at 1450°C for 2 h were 17.42 ± 0.06 GPa and 8.22 MPa·m1/2, respectively. [ABSTRACT FROM AUTHOR]

Ti(C, N)‐based cermets have been considered to be the most potential candidates for WC‐Co cemented carbides as tool material due to their various advantages. However, the trade‐off between hardness/strength and toughness limits their further application. Herein, we present new (Ti, W, Mo, Cr)(C, N)‐based cermets showing superior mechanical properties with hardness of 1525 MPa, transverse rupture strength of 2428 MPa, and fracture toughness of 11.44 MPa·m1/2 by compositional and interfacial modification. The strengthening and toughening mechanisms were revealed by experimental observation and theory calculation. It could be clarified that the high elastic modulus caused by a polar covalent bond in the hard phase and solid solution strengthening of the binder phase attributed to the hardness. The strong interface bonding between the core/rim, inner/outer rim, and rim/binder phases stemming from the composition optimization contributed to super crack resistance. Intergranular fracture in submicron‐scaled hard phases led to the crack deflection, transgranular fracture in the micron‐scaled hard phases consumed more energy due to their high intrinsic hardness and excellent interface coordination. The synergy of multi‐scaled hard particles brought about excellent comprehensive mechanical properties. [ABSTRACT FROM AUTHOR]

Cermet has broad applications in electronics, but achieving stable ceramic‐metal contact has always been a challenge, particularly at hot temperature and large deformation conditions, due to the significant differences in thermal expansion coefficient and stiffness of ceramics and metals. Here, stress matching and strong interphase bonding at the heterogenous ceramic‐metal contact are realized by using flexible ceramics, leading to stable applications in flexible fire‐resistant pressure tactile sensors. Cu/Au nanolayers are deposited first onto the toughened flexible SiO2 nanofibers with a chemical plating method to form sensitive interdigital electrode sensors, then use an in situ thermal reaction strategy to form conformal and interlocked Au3Cu and CuSiO3 interphases, which enhance the mechanical thermal stability of the ceramic‐metal contact. With deep learning technique, the as‐fabricated intelligent pressure tactile gloves can accurately recognize the human body parts in low‐visible burning environments and show a long‐term stability over 1000 cycles with a high sensitivity of 112.18 kPa−1, which is important for developing intelligent firefighting. [ABSTRACT FROM AUTHOR]

The use of metal-coated ceramic powders not only effectively enhances the wettability of the metal–ceramic interface but also promotes a more uniform microstructure in Ti(C,N)-based cermets, which is advantageous for improving their mechanical properties. In this study, ultrafine Co- and Ni-coated (Ti,W,Mo,Ta)(C,N) powders were synthesized via the spray-drying-in-situ carbothermal reduction method. Subsequently, Ti(C,N)-based cermets were effectively fabricated using the as-prepared ultrafine Co- and Ni-coated (Ti,W,Mo,Ta)(C,N) powders. The impact of reaction temperature, heating rate, and isothermal time on the phase and microstructure of prepared powders was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Additionally, the microstructure of the as-sintered cermets was experimentally investigated. The findings reveal that the complete reduction of Co and Ni metal salts, pre-coated on the surface of (Ti,W,Mo,Ta)(C,N) particles, can be achieved through rapid heating (10 °C/min) in a specific temperature range (600–1000 °C) with an isothermal time of 3 h at a lower reduction temperature (1000 °C). The synthesized powders have only two phases: the (Ti,W,Mo,Ta)(C,N) phase and Co/Ni phase, and no other heterogeneous phases were observed with an oxygen content of 0.261 wt.%. Notably, the conventional core–rim structure was not dominant in the cermets obtained from the prepared Co- and Ni-coated (Ti,W,Mo,Ta)(C,N) powders. Moreover, the heterogeneous segregation effect of the Co/Ni coating on the ultrafine powder particles resulted in a finer microstructure than the traditional cermets with the same composition. However, the grain size is mainly in the range of 0.5–0.8 μm. The weaker residual stresses at the core and rim interfaces and the finer particle distributions could theoretically enhance the toughness of Ti(C,N)-based cermets, simultaneously. [ABSTRACT FROM AUTHOR]

Background: Marginal fit significantly impacts the long-term success of dental restorations. Different pattern fabrication methods, including hand-waxing, milling, or 3D printing, may affect restorations accuracy. The effect of porcelain firing cycles on the marginal fit of metal-ceramic restorations remains controversial, with conflicting findings across studies. Purpose: The aim was to evaluate the potential effects of multiple porcelain firings (3, 5, 7 cycles) as well as pattern fabrication method (conventional hand-waxing, milling, and 3D printing) on the marginal adaptation of 3-unit implant-supported metal-ceramic fixed partial dentures. It was hypothesized that neither the wax pattern fabrication method nor repeated ceramic firings would significantly affect the marginal adaptation of metal-ceramic crowns. Methods: In this in-vitro study, 30 Cobalt-Chromium alloy frameworks were fabricated based on pattern made through three techniques: conventional hand-waxing, CAD-CAM milling, and CAD-CAM 3D printing (n = 10 per group). Sixteen locations were marked on each abutment to measure the vertical marginal gap at four stages: before porcelain veneering and after 3, 5, and 7 firing cycles. The vertical marginal gap was measured using direct microscopic technique at ×80 magnification. Mean vertical marginal gap values were calculated and two-way ANOVA and Tukey's post hoc tests were used for inter-group comparisons (α = 0.05). Results: The 3D printing group showed significantly lower (P<0.001) mean vertical marginal gaps (60–76 μm) compared to the milling (77–115 μm) and conventional hand-waxing (102–110 μm) groups. The milling group exhibited a significant vertical gap increase after 3 firing cycles (P<0.001); while the conventional (P = 0.429) and 3D printing groups (P = 0.501) showed no significant changes after 7 firing cycles. Notably, the vertical marginal gap in all groups remained below the clinically acceptable threshold of 120 μm. Conclusion: CAD-CAM 3D printing provided superior marginal fit compared to CAD-CAM milling and conventional hand-wax pattern fabrication methods. The impact of porcelain firing on the mean marginal gap was significant only in the milling group. All three fabrication techniques yielded clinically acceptable vertical marginal adaptation after repeated firings. Additive manufacturing holds promise to produce precise implant-supported prostheses. [ABSTRACT FROM AUTHOR]

High Velocity Oxygen Fuel (HVOF) process enables superior properties and is foreseen as a suitable candidate for deposition of hard chromium alternative coatings over the other surface hardening techniques like cladding/deposition through electrolysis/CVD methods, owing to the widespread adaptability and preference in aerospace industry, in particular landing gear mechanism and associated modules that operating in severe environments encountering abrasion, erosion, sliding and fretting wear. Cermet coatings are very often utilised to intensify the wear and corrosion resistance of a wide range of engineering components. The objective of this work is to develop thermally sprayable oxides, nitrides and carbides of WC and Cr3C2 cermet coatings on AISI 4340 steel by HVOF technique. The modified surface is characterised by SEM/EDAX study, followed by the evaluation of Porosity and Microhardness of the modified different speeds and loads. The study unveiled that of all the stated coatings, the blend of WC-Co-VC matrix yields superior hardness, Coefficient of friction and lower order of porosity. The observation forefronts the enhancement of wear properties in terms of surpassing wear resistance and declining trend in volume loss compared to other compositions. [ABSTRACT FROM AUTHOR]

The study investigated the microstructures, residual stress and mechanical properties of double carbides cermet coatings manufactured on AZ31 magnesium alloy substrate by high-velocity oxy-fuel spraying (HVOF). The HVOF spraying was carried out using a JP 5000 TAFA spray system and the commercially available powder WC-20Cr3C2-7Ni was used to manufacture coatings. The variable process parameter was spray distance (320, 360 and 400 mm). The top surfaces of the manufactured coatings are typical for HVOF coatings and is relatively smooth. Nevertheless, some irregularities and voids are observed. All coatings exhibit dense structure with relatively low porosity level (below 3 vol. %) as well as a robust mechanical binding to the substrate which indicates high adhesion. More deep microstructure analysis carried out by TEM microscopy revealed two types of precipitation: WC hexagonal phase in the space group P-6m2 with irregular shape and size as well as Cr7C3 orthorhombic one, in the space group P nma with a rounded shape and regular size. Phase composition after the spraying process indicates the hexagonal WC phase as the main one. Additionally, two chromium carbides phases, Cr3C2 and Cr3C7 have been identified. A small peak of hexagonal W2C carbide was found as well. Analysis of residual stress showed that both components of linear stress for all deposited coatings have a compressive nature. The increasing spray distance caused an increase of the linear stress values, from – 72.7 up to – 131.5 MPa for δ11 and from – 57.2 up to – 112.2 MPa for δ22. Such values could suggest that thermal stress generated during coating deposition was also low. In the case of the shear stress the values are much lower than linear one, but with the same tendency, increasing with longer spray distance: 14.2, 21.0 and 32.2 MPa for 320, 360 and 400 mm, respectively. The obtained results of HIT show a slight influence on the spray distance. With the increasing spraying distance, the value of hardness decreasing: 12.96, 12.53 and 11.76 GPa according to SD equal to 320, 360 and 400 mm, respectively. Similar was in the case of the EIT values: 315, 309 and 304 GPa for 320, 360 and 400 mm, respectively. All values of the fracture toughness were in the range between 3.5 and 4.0 MPa m1/2, with little influece of the spray distance. [ABSTRACT FROM AUTHOR]

This work aims to develop Co and Ni-free Ti(C,N)–Fe-based cermets which are essential for developing cermets in the direction of green and low-cost materials. TiC and Ti(C,N) -based cermets prove to evince excellent mechanical properties at high temperatures as compared to conventional WC-based cermets. A binder system based on Cr, Mo, Fe, and their alloys may offer a viable solution to replace carcinogen elements such as Ni and Co from the binder. In the present work, high chromium Ti(C,N)-30 wt% FeCrMo cermets were fabricated by using Pressureless liquid-phase sintering. Samples at different sintering temperatures were prepared to investigate the influence of the temperature on microstructural formation and their mechanical characteristics. Scanning Electron Microscopy (SEM) is employed to observe the microstructural formation. A microstructural analysis of the consolidated cermets reveals that the addition of Mo to the binder system and an increase in sintering temperature affect the carbide grain size and densification, which ultimately affect their mechanical characteristics. The hardness and fracture toughness were determined by the Vickers hardness test and Indentation fracture toughness (IFT) method respectively. The maximum Hardness, Fracture toughness, and Transverse rapture strength achieved for the Ti(C,N)–FeCrMo-based green cermets are 665 ± 6.7 MPa, 1396 ± 26 HV 30, and 9.23 ± 0.12 MPa m1/2 respectively. [ABSTRACT FROM AUTHOR]

The microstructure and mechanical properties of the vacuum sintered (80- x)TiB 2 - x WC −10Co-10 Ni (x = 0, 2.5, 5, 7.5, 10, 12.5) cermets were studied by XRD, SEM, EPMA and TEM analysis. The results show that the TiB 2 -7.5 WC based cermets exhibited excellent comprehensive properties with relative density, Rockwell hardness, transversal rupture strength and fracture toughness of 99.44 ± 0.18 %, 17.50 ± 0.71 GPa, 2108 ± 29 MPa, and 12.21 ± 0.29 MPa m1/2, respectively. The XRD diffraction peaks of TiB 2 , W 2 CoB 2 , WB and CoNi binder were detected in cermets with WC addition. The HCP TiB 2 core-FCC (Ti, W, Co, Ni) (B, C) rim structure was formed in TiB 2 -WC based cermets with FCC CoNi binder. The coherent interface formed between the TiB 2 core and (Ti, W, Co, Ni) (B, C) rim phase, as well as the amorphous CoNi thin layer formed at the interface between (Ti, W, Co, Ni) (B, C) rim and CoNi binder phase, both of them were suggested to improve the interfacial bonding strength of TiB 2 -WC based cermets. [ABSTRACT FROM AUTHOR]

In this study, TiC x -Cu (x = 0.5, 0.6, 0.7) cermets were prepared combined with subsequent solution treatment, and the influences of solution treatment on the microstructures and mechanical properties were analyzed. The fracture mechanisms of cermets before and after solution treatment were mainly observed and analyzed. The results show that solution treatment can significantly improve the comprehensive mechanical properties of TiC x -Cu cermets. The fracture toughness K IC of TiC 0.5 -Cu and TiC 0.7 -Cu cermets increased by 28% and 11%, respectively. The improvements of the comprehensive properties of TiC x -Cu cermets were benefited by the reduction of the content of hard brittle intermetallic compound Cu 4 Ti and the refinements of the grain size of Cu. [ABSTRACT FROM AUTHOR]

Background: No systematic review or meta-analysis has been identified that provides a clinician's perspective on the shade selection process for ceramic restorations. The aim of the present systematic review is to find and systematize the available knowledge by referring to the methods to assess the color of dental ceramics. Methods: The final search was performed on 10 December 2023 in six search engines. The keywords used in the search strategy were as follows: ("color matching" OR "shade matching" OR "color measurement" AND "porcelain" OR "dental ceramics") AND "dentistry" AND "accuracy". Results: The search strategy identified 139 potential articles. After the screening process, sixteen articles were included in the review. Conclusions: In conclusion, the most common method, the visual method, has lower accuracy and repeatability. Devices like spectrophotometers and colorimeters provide precise, repeatable, and objective measurements, but fail to be widely applied in everyday clinical practice. Clinicians should not rely solely on their senses for shade determination, but should turn to quantitative methods. Colorimetric devices connected to mobile applications are an interesting and useful tool. Software and apps based on artificial intelligence are emerging as promising tools, but they require further research. [ABSTRACT FROM AUTHOR]

In this study, the performance and degradation behavior of thin-film SOFCs are investigated under various syngas fuel conditions, including CO, H2, and a nickel-yttria-stabilized zirconia (Ni-YSZ) anode composition. By increasing the YSZ ratio, three cell types (Cell N, Cell NY, and Cell NYY) are analyzed under three different fuel conditions. This research, conducted at 650 °C, establishes Cell NY as the top-performing variant, whereas Cell N experiences significant degradation owing to metal dusting caused by carbon deposition. The DRT curve peaks confirm severe Ni agglomeration for the NYY and N cells under these conditions, whereas Cell NY consistently maintains the highest performance. These results reveal the impact of carbon-deposition-induced metal dusting and Ni agglomeration on cell performance. This study highlights the importance of understanding and managing these degradation factors to enhance the reliability and efficiency of syngas-fueled thin-film SOFCs. • Thin-film SOFCs' performance and degradation were studied under diverse syngas and anode conditions. • Degradation varied at two temperatures, based on anode's YSZ ratio. • DRT distinguished degradation causes: metal dusting and Ni agglomeration. • Results show carbon-induced metal dusting and Ni agglomeration impact. [ABSTRACT FROM AUTHOR]

This paper introduces a novel process, known as pre-solid phase sintering-assisted pressureless infiltration (PSPS-PI), aimed at addressing issues related to the segregation of hard particles and excessive porosity in the manufacturing of lightweight cermet based on TiC. The PSPS-PI process involves compressing a green TiC powder compact with a minor Ni powder addition, followed by vacuum-based solid-phase sintering to create a fully consolidated TiC preform. This study explores the influence of TiC particle size and Ni content on the microstructure and properties of TiC–Cu composites, conducting a comparison with direct pressureless infiltration (D-PI). The results indicate that the high-melting-point Ni element promotes the formation of sintering necks between TiC and Ni, aiding in the consolidation of TiC particles. The stable skeleton ensures that TiC particles remain in their initial positions during subsequent pressureless infiltration, effectively preventing TiC powder segregation. TiC and Ni create a dissolutive wetting system during pressureless infiltration. The formation of the Ni2SnTi intermetallic compound significantly enhances the wettability with Cu alloy, leading to a reduction in porosity and the occurrence of crack defects within the composite. As particle size decreases, the preform's porosity decreases, resulting in a reduced proportion of soft metal binder and lower residual stress. Consequently, finer TiC powder leads to improved cermet hardness and a reduction in the number of micro-crack defects. In general, PSPS-PI allows for the attainment of low porosity, a uniform microstructure, enhanced hardness, and outstanding wear resistance in the lightweight cermet based on TiC with the appropriate TiC particle size (D50 = 10.2 μm), achieving a remarkable hardness of 642.9 (Hv30) and excellent toughness. [ABSTRACT FROM AUTHOR]

Five high-entropy carbonitride ceramic (HECN) powders consisting of pentavalent cations (Ti,W,Mo,Nb,Ta) (C 0.78 ,N 0.22) are synthesized by the carbothermal reduction-nitridation (CRN) method. Subsequently, a series of 85HECN-7.5Co-7.5Ni(wt.%) cermet is fabricated employing the powder metallurgy method. The phase constitution, microstructure, and composition distribution of the HECN powders are analyzed. The synthesis temperature of the HECN powders is reduced by 100 °C compared to the non-high-entropy (Ti,Me) (C,N) ceramic powder when ΔS mix >1.5R, which demonstrates that the high entropy effect promotes the synthesis of solid solution powder. A uniform element distribution, 600 nm single-phase (Ti 0.6 ,W 0.1 ,Mo 0.1 ,Nb 0.1 ,Ta 0.1) (C 0.78 ,N 0.22) high-entropy ceramic solid solution powder, could be synthesized through the CRN at 1400 °C for 2 h under a 2 kPa N 2 atmosphere. Subsequently, five types of (Ti,W,Mo,Nb,Ta) (C 0.78 ,N 0.22)-Co-Ni high-entropy cermets are prepared via vacuum sintering at 1500 °C for 1 h. Among them, the (Ti 0·6 W 0·1 Nb 0·1 Ta 0·1 Mo 0.1) (C 0.78 ,N 0.22)-Co-Ni cermet exhibited the most outstanding performance with a Vickers hardness of 2053.4 HV, fracture toughness of 12.3 MPa m1/2, and TRS of 1220 MPa, which present an increase of 17.0 %, 16.2 %, and 60.0 %, respectively, compared with the non-high-entropy TiCN–Co–Ni cermet. It was attributed to the addition of high-entropy ceramic powders, which resulted in fine grain strengthening, severe lattice distortion, and long crack deflection paths. This study presents a novel approach for the preparation of high-entropy Ti(C,N)-based cermets. [ABSTRACT FROM AUTHOR]

Ti(C,N)-based cermet is a kind of composite material composed of a metal binder phase and a Ti(C,N)-hard phase, which is widely used in the fields of cutting machining and wear-resistant parts due to its high hardness, good toughness, wear resistance, and chemical stability. In recent years, the research on the replacement of traditional Ni, Co, and Fe binder phases by novel binder phases such as intermetallic compounds and high-entropy alloys has made remarkable progress, which significantly improves the mechanical properties, wear resistance, corrosion resistance, and high-temperature oxidation resistance of Ti(C,N)-based cermets. This paper reviews the latest research results, summarizes the mechanism of the new binder to improve the performance of metal–ceramics, and looks forward to the future research directions. [ABSTRACT FROM AUTHOR]

In this work, to explore potential substitutions for the Co binder phase, ultrafine-grain WC-based cermets with various binder phases of Co, Ni and AlCoCrNiFeCu HEA were prepared using the SPS method. Based on SPS, WC-based cermets were fabricated at higher speed, showing fine carbide particles less than 410 μm. The microstructure, mechanical properties and wear properties were systematically evaluated. By comparison, the grain size of WC was the lowest for WC-10Co, while WC-10 HEA cermet held the coarsest WC particles. The hardness and fracture toughness of WC-10 HEA were the best among all three samples, with values of 93.2 HRA and 11.3 MP·m1/2. However, the bending strength of WC-10HEA was about 56.1% lower than that of WC-10Co, with a value of 1349.6 MPa. The reduction in bending strength is attributed to the lower density, formation of a newly Cr-Al rich phase and coarser WC grains. In dry sliding wear conditions, WC-10 HEA showed the lowest wear rate (0.98 × 10−6 mm3/(N·m)) and coefficient of friction (0.19), indicating the best wear resistance performance. This reveals that WC-based cermet with a HEA binder phase has superior wear performance due to the higher hardness and good self-lubricating effect of the wear products. [ABSTRACT FROM AUTHOR]

The metal–dielectric cermet (metal‐rich) material is utilized for turning the dispersion properties of surface plasmon in GaN‐light‐emitting diode. The designed structure contains a cermet layer coated on p‐GaN layer. The optimized ingredients in the cermet material and thickness of the cermet layer are obtained by the simulations. For enhancing the extraction of surface plasmon, the designed structure is further optimized by inserting a layer of low refractive index. The calculated results indicate that the Purcell factor in optimized structure is greater than 100 over the emission spectrum and the extraction efficiency of surface plasmon is effectively improved. The photoluminescence (PL) experiment by bottom excitation demonstrates that peaks of PL spectra of the designed and optimized samples are enhanced by 1.6 and 3.4 times, respectively, compared with the sample covered by Ag film. Compared with the naked sample, peaks of PL spectra of bottom pumping of optimized and designed samples are enhanced by 36.3 and 17.2 times, respectively. Peaks of normalized PL spectra by top excitation of optimized and designed samples are enhanced by 29.0 and 9.1 times, respectively. The results of numerical calculations are substantially consistent with the results of PL tests. [ABSTRACT FROM AUTHOR]

Five high-entropy carbonitride ceramic (HECN) powders consisting of pentavalent cations (Ti,W,Mo,Nb,Ta) (C 0.78 ,N 0.22) are synthesized by the carbothermal reduction-nitridation (CRN) method. Subsequently, a series of 85HECN-7.5Co-7.5Ni(wt.%) cermet is fabricated employing the powder metallurgy method. The phase constitution, microstructure, and composition distribution of the HECN powders are analyzed. The synthesis temperature of the HECN powders is reduced by 100 °C compared to the non-high-entropy (Ti,Me) (C,N) ceramic powder when ΔS mix >1.5R, which demonstrates that the high entropy effect promotes the synthesis of solid solution powder. A uniform element distribution, 600 nm single-phase (Ti 0.6 ,W 0.1 ,Mo 0.1 ,Nb 0.1 ,Ta 0.1) (C 0.78 ,N 0.22) high-entropy ceramic solid solution powder, could be synthesized through the CRN at 1400 °C for 2 h under a 2 kPa N 2 atmosphere. Subsequently, five types of (Ti,W,Mo,Nb,Ta) (C 0.78 ,N 0.22)-Co-Ni high-entropy cermets are prepared via vacuum sintering at 1500 °C for 1 h. Among them, the (Ti 0·6 W 0·1 Nb 0·1 Ta 0·1 Mo 0.1) (C 0.78 ,N 0.22)-Co-Ni cermet exhibited the most outstanding performance with a Vickers hardness of 2053.4 HV, fracture toughness of 12.3 MPa m1/2, and TRS of 1220 MPa, which present an increase of 17.0 %, 16.2 %, and 60.0 %, respectively, compared with the non-high-entropy TiCN–Co–Ni cermet. It was attributed to the addition of high-entropy ceramic powders, which resulted in fine grain strengthening, severe lattice distortion, and long crack deflection paths. This study presents a novel approach for the preparation of high-entropy Ti(C,N)-based cermets. [ABSTRACT FROM AUTHOR]

Introduction: The management of well-fixed femoral stems in revision total hip arthroplasty (rTHA) remains a subject of debate, with concerns over potential complications arising from stem retention. This study aimed to investigate the re-revision rates due to aseptic loosening of the stem, overall re-revision rates, dislocation rates, and factors influencing these outcomes in rTHA with a retained well-fixed femoral stem. Materials and methods: A systematic search was conducted across several databases including PubMed, EMBASE, and CENTRAL to identify pertinent publications from their inception through 2023. We specifically focused on studies that reported outcomes of rTHA with retained well-fixed femoral stems. The study designs incorporated in our research encompassed both cohort studies and case series studies. Thirty-five studies involving isolated acetabular revision and retaining the stem were included, representing a total of 3497 patients. Data extraction was tailored to the study questions. Meta-analyses, meta-regression, and subgroup analyses were conducted to evaluate the outcomes and their relationship with various factors. Pooled results, meta-regression, and subgroup analyses were performed using random-effects models. To assess and reduce bias, we employed Egger's test and the trim and fill method. Results: The meta-analysis included 3497 patients with a mean follow-up of 9.28 years. The 10-year risk of re-revision after retaining femoral stem using highly cross-linked polyethylene was 1.7% (95% CI 1.1%–2.3%; I2: 60%) for stem aseptic loosening and 8.8% (95% CI 6.2%–11.4%; I2: 78%) overall re-revision. Dislocation risk was 5.7% (95% CI 4.1–7.0%; I2: 61%). Ceramic heads showed lower stem failure risk than metal heads in long-term follow-ups (P < 0.001). The posterolateral approach in revision surgery resulted in better long-term outcomes compared to the direct lateral approach (P < 0.001). Follow-up duration, timeline of study, Harris Hip Score, type of stem fixation, femoral head material, BMI, age, stem age, and surgical approach were evaluated as influential factors on these outcomes. Conclusion: The re-revision rate due to aseptic loosening of the retained stem during rTHA was found to be significantly low, supporting the idea of retaining well-fixed stems during rTHA. The overall re-revision and dislocation rates also presented comparable or better outcomes to prior studies. A range of factors, including the use of highly cross-linked polyethylene and ceramic femoral heads, was found to influence these outcomes. Level of evidence: IV. PROSPERO registration number: CRD42022351157. [ABSTRACT FROM AUTHOR]

Purpose: Different technologies may currently be used to produce dental prostheses, such as additive manufacturing and traditional milling. This study aims to evaluate and improve the fabrication process for hot-pressed porcelain dental prostheses and compare the use of masked stereolithography apparatus (MSLA) casting to computer-aided design/computer-aided manufacturing (CAD/CAM) casting. The cost-benefit analysis of producing dental prostheses through various technologies, including additive manufacturing and traditional milling, has not been fully explored. The cost of materials and processes used to produce prostheses varies based on complexity of design and materials used, and long-term effects, such as durability and wear and tear, must be taken into account. Design/methodology/approach: Using key elements of part costs and estimation cost models, a multivariable approach was used to evaluate the practicality of the recommended strategy and process improvement. Findings: The research found that MSLA casting provides a higher return on investment than CAD/CAM casting, and the optimized production process could be more suitable for the size and annual demand for prostheses. Originality/value: Overall, this study highlights the need for a more comprehensive understanding of the cost-benefit analysis of different dental prosthesis production methods and emphasises the importance of evaluating long-term effects on the cost-benefit analysis. [ABSTRACT FROM AUTHOR]

Biomimetic micro-laminated structures are gaining traction for their potential to enhance the mechanical properties of composites. A salient challenge lies in fabricating this intricate layered construct with good interfacial adhesion. In this research, we developed a micro-laminated metal/ceramic composite utilizing CoCrCuFeNi as the infiltration layers. However, after CoCrCuFeNi infiltration, the metal layer phase of cermet transforms into FCC + BCC, which belongs to the category of medium entropy alloy. The mechanical properties displayed a direct relationship with the TiC skeleton's content. Notably, cermet with a TiC volume fraction of 65% exhibited bending strength of 770 MPa, crack-initiation toughness (K IC) of 10.31 MPa•m1/2, crack-propagation toughness (K JC) of 35.1 MPa•m1/2. Mechanisms such as crack deflection and branching acted at the crack tip, significantly reducing peak stress. Contrasting prior studies marked by pronounced interface delamination, the robust adhesion between CoCrCuFeNi and TiC in this study facilitated the congruence of strength and toughness. Our findings introduce a pioneering methodology for designing laminated metal/ceramic composites with CoCrCuFeNi infiltration layers, aiming to achieve superior strength and toughness. [ABSTRACT FROM AUTHOR]

The principal objective of this study is to investigate the anti-penetration performance of ceramic composite armor and to explore the impact of ceramic structural and performance parameters on this ability. We conducted both experimental and numerical simulations on four types of ceramics widely used in this field—B 4 C, SiC, Si 3 N 4 , and Al 2 O 3 , using them as the faceplate, and Kevlar fiber board as the backing, to ascertain the influence of the ceramic's structure and performance parameters on its anti-penetration properties. Given the context where Kevlar fiber serves as the backing, an extensive damage analysis was carried out from both macro and micro perspectives, focusing on the projectile-ceramic-fiber interplay. We deployed the LS-Dyna finite element software to simulate the penetration behavior of these ceramics, and a high level of agreement was observed with experimental results, thus validating the relevance of the parameters used. The results indicate that the principal failure modes of the projectile core and ceramics include tensile shear and compressive shear, leading to fractures. The backing's main failure mode consists of tensile fracture and shear fracture. As the hardness of the ceramics increases, there is a slight decrease in their anti-penetration performance, suggesting that this performance may not be significantly related to hardness as a single variable. Conversely, an increase in fracture toughness and a decrease in brittleness can lead to enhanced anti-penetration performance. Utilizing numerical simulations, an assortment of the four ceramics was tested. When the harder ceramics are placed at the forefront and those with higher toughness at the rear, the energy absorption per unit area increases to a certain extent. Following a comparative analysis of different ceramic combinations, when B 4 C is combined with SiC, Al 2 O 3 , and Si 3 N 4 , placing B 4 C in the front layer increased energy absorption efficiency per unit area by 28.27%, 7.78%, and 18.96% respectively, compared to when it was placed at the back. Furthermore, the combinations of Al 2 O 3 with Si 3 N 4 and SiC respectively resulted in an enhanced energy absorption capability per unit area by 5.96% and 1.72%. A dual-layer ceramic structure with high hardness and high fracture toughness can significantly improve the anti-penetration efficiency of the composite armor. [ABSTRACT FROM AUTHOR]

A TiCN-Co-Cr3C2-based cermet, with the addition of 5wt. % and 10wt. %Si3N4 and a reference sample without Si3N4 addition were prepared by the spark plasma sintering technique. The average hardness and fracture toughness of the 90TiCN-5Co-5Cr3C2(SN00) cermet-sintered specimens were e14.85±3.11 GPa and 6.78±0.61 MPaÖm, respectively. The cermet composition 85TiCN-5Co-5Cr3C2-5 wt. % Si3N4(SN05) enhanced the hardness and fracture toughness to 20.90±0.825 GPa and 7.23±0.45 MPaÖm, respectively. Further addition of 10 wt%Si3N4 with 80TiCN-5Co-5Cr3C2(SN10) decreased the hardness value to 16.18±0.279 GPa due to a decrease in the density of defects. However, the fracture toughness steadily increased to 9.34±3.10 MPaÖm. The cermet composition 85TiCN-5Co-5Cr3C2-5Si3N4 (SN05) showed an appreciable improvement in hardness and toughness values due to the formation of a core-rim structure, with the core consisting of TiCN and the rim with TiN, TiO2, TiSi, Co2C, CrN and Cr2Si. [ABSTRACT FROM AUTHOR]

In this study, a novel attempt was made to deposit 86WC-10Co-4Cr cermet layer on 1.2709 tool steel substrate prepared by selective laser melting (SLM) process using detonation spraying method. The laser power of 350 W, scan speed of 25 mm/s, hatch spacing of 0.15 mm, and layer thickness of 50 µm were used to fabricate samples at 45° build orientation. The calculated volumetric energy density for fabricating the samples was 1867 J/mm3. The SLM printed samples were annealed and air cooled at 500 °C in a box furnace with a dwell time of 6 h. The average particle size of the powder measured before and after the ball milling process was 237.49 and 43.06 μm, respectively. A coating thickness of 100 μm was targeted using the detonation spraying process. An average spray loss of 13% was observed during cermet coating. The results were compared between the as-built specimen, the heat treated specimen and the 86WC-10Co-4Cr coated specimen. The average Vickers microhardness of the coated sample was found to be 81.04 and 48.96% superior to the as-built and heat treated samples. The average contact angles measured from the as-built, heat treated and coated samples were 82.5°, 64° and 93.9°, respectively, indicating the superior hydrophobic surface in the coated sample. The coated sample offered reduced abrasive wear, improved corrosion inhibition, and better 2D and 3D surface roughness properties than the as-built and heat treated samples, which promises its further use in cermet-based rapid tooling applications. [ABSTRACT FROM AUTHOR]

The objects of the study were TiN-Mo cermet, as the final product of the reaction. Thermogravimetric study of cermets of the TiN + Mo and 2TiN + Mo systems revealed two exothermic peaks at temperatures of 560 °C and 700 °C, which may be related to the oxidation of dissolved and of titanium. The increase in mass after a complete heating-cooling cycle at the maximum temperature of 950 °C was 5%. [ABSTRACT FROM AUTHOR]

To support the structural optimization design of metal-ceramic armor against penetration protection performance, this paper optimizes the armor in terms of protection material, armor structure, and bullet resistance mechanism, and envisages a new metal-constrained ceramic composite armor, which overcomes the disadvantages of ceramic material fragility. A coupled finite element-smooth particle hydrodynamics (FEM-SPH) algorithm is used to simulate the penetration process, and the influence of ceramic unit shape and size on the armor protection performance is investigated by quantitatively comparing the bullet energy loss, velocity change, penetration depth, and other indicators that reflect the ballistic protection mechanism. The results show that metal-confined ceramic armor has repairable performance, and filling ceramic units can reduce armor failure area, save armor repair time, and extend armor service life. When the velocity of the projectile is less than 500 m/s, the damaged area of the armor filled with small-sized unit ceramics (1/4 bullet caliber) is small and easy to repair; when the velocity of the projectile is greater than 500 m/s, the armor filled with large-sized unit ceramics (2 times the bullet caliber) can effectively increase the bullet residence time and improve the armor's resistance to elasticity. The results of this paper can provide a reference for the optimal design of the armor structure. [ABSTRACT FROM AUTHOR]

Electrochemical tests were conducted to assess the corrosion performance of a developmental multiphase cermet nuclear waste form in different conditions. Corrosion currents were monitored as the surface equilibrated in an acidic brine solution during potentiostatic tests at different imposed potentials. Electrochemical impedance spectroscopy was used to quantify differences in the electrical properties of surfaces stabilised at different potentials. The passivating oxides that will stabilise the surface under disposal conditions are formed and maintained during testing. The measured corrosion currents were two orders of magnitude lower for passivated surfaces than for polished surfaces over a wide range of redox conditions. The electrochemical results were correlated with microscopic analyses of the corroded surfaces and physical models of the surface passivation and degradation processes are proposed. The measured corrosion rates are suitable for the long-term performance modeling of cermet nuclear waste forms. [ABSTRACT FROM AUTHOR]

This paper is devoted to the influence of substrate preheating on the structure of cermet coatings made of TI–6AL–4V alloy reinforced with B4C particles using direct metal deposition. Coatings with a 15% mass fraction of B4C were obtained for the first time. It is shown that substrate preheating makes it possible to produce cermet coatings without cracks. In tribological tests, the wear scar volume of the cermet coating decreased by a factor of eight compared to the coating with a 10% mass fraction of B4C. [ABSTRACT FROM AUTHOR]

The deposition process of a nickel-based cermet coating with a high (60 wt.%) mass content of tungsten carbide was investigated. The results showed preheating the substrate to 500°C prevented the formation of cracks and pores in the coating. This is because preheating reduces the thermal shock between the substrate and the coating, leading to better adhesion and fewer defects. Additionally, synchrotron radiation was used to analyze the phase composition of the resulting composite. It was found that additional heating of the sample to 500°C during surfacing did not cause significant changes in the phase composition of the composite. [ABSTRACT FROM AUTHOR]

Background: Different treatment options exist for replacement of an anterior tooth, and as implant‐supported single crowns (ISSC) and resin‐bonded fixed dental prosthesis (RBFDPs) both are widespread treatment options, it is of clinical relevance to know which treatment modality can be considered superior. Purpose: The purpose of this comparative study was to evaluate the 3‐ and 5‐year survival and failure rate of tooth‐supported resin‐bonded fixed dental prosthesis compared to implant‐supported single crowns. The null hypothesis was that there was no significant difference in survival rate, occurrence of complications or patient‐reported outcome between RBFDPs and ISSCs. Materials and Methods: A total of 45 resin‐bonded FDPs were inserted in 27 young patients (test group) with tooth agenesis in the anterior part of the maxilla or mandible and a control group of 28 patients also with tooth agenesis in the anterior region but treated with 40 implant‐supported single crowns were included in this study. All patients and treatments were followed with a baseline and a 3‐ or 5‐year examination. All patients had to fill out an Oral Health Impact Profile (OHIP‐49) questionnaire at baseline and at the 3‐ or 5‐year examination. The restorations were evaluated according to the Copenhagen Index Score (CIS). Results: For the RBFDP (test) group there was an 82% survival rate and 18% failure rate, that is, four RBFDPs were not in situ after 3 years and four RBFDPs were not in situ after 5 years. Correspondingly, the ISSC showed a survival rate of 98% and a failure rate of 2%, that is, only one failure (ceramic fracture) after 3 and none after 5 years. Of the 82% RBFDPs in situ, there were no complications in 78% of the cases, whereas 22% had complications after 3 (4 complications) and 5 years (4 complications). There were 92% of the ISSCs without any complications and 8% (ie, 3 ISSCs) with complications after 3 or 5 years. In general, there was a significant reduction in the OHIP‐49 scores, for example, an improved oral health quality of life for both treatment options. Conclusion: The results of this study indicate that ISSCs have lower complication and failure rates than RBFDPs. In general, the OHIP‐scores were significantly reduced regardless of whether RBFDPs or ISSC were used. [ABSTRACT FROM AUTHOR]

Thermal spraying by flame is one of the methods employed in the treatment of cracks and pores that occur in materials subjected to elevated temperatures or varying climatic conditions. Nickel was used as a base material and reinforced with two ceramic materials, nickel oxide, NiO, at a fixed rate of 5%, and chromium oxide as the second material. The study involved using Triple Cr2O3 with varying reinforcement percentages (10%, 20%, 30%, 40%, and 50%). The materials were mixed for a duration of two hours, following the specified ratios. The coating process was carried out on a base of out-of-service turbine blades cut into coupons. The coating was subjected to a heat treatment at a temperature of 1000 °C for a duration of two hours. Various structural and physical tests were conducted on the resulting system to examine its crystalline structure. The scanning electron microscope analysis revealed a consistent pattern of regularity, with the most optimal outcome observed at 50%Cr2O3. Under optimal conditions and with a sintering rate of 50%, the material achieved a real density of 7.4 g/cm3, a real porosity of 18%, a water absorption rate of 0.893%, a Brinell hardness value of 770 Kg/mm2, and a wear rate of 1.31 × 10−8 g/cm of travel. [ABSTRACT FROM AUTHOR]

To promote the utilization of Mo 2 NiB 2 –Ni cermet under sulfuric acid drew corrosion conditions, it is essential to elucidate the resistance mechanism of these cermets to sulfuric acid corrosion. In this study, the corrosion behavior of Mo 2 NiB 2 –Ni cermets with different Ni content in 90 wt % H 2 SO 4 solution at 110 °C was investigated, and the corrosion resistance mechanism was analyzed. The results reveal that the corrosion weight losses and corrosion rates of the cermets decreased with increasing Ni content. Mo 2 NiB 2 –Ni cermets with higher Ni contents exhibited improved corrosion resistance. This improvement can be attributed to the generation of a considerable amount of NiSO 4 corrosion products from the Ni binder phase corroded by H 2 SO 4 , which led to the subsequent formation of a large-scale, flat, and dense corrosion products layer with a certain thickness. This effectively prevented further erosion of the inner matrix and improved the corrosion resistance of the cermet. Additionally, the electrochemical results indicate that the corrosion product layer hindered the passage of electric charges through the layer, which inhibited the corrosion reaction. [ABSTRACT FROM AUTHOR]

The versatility of the spinel (AB2O4) oxides means they are of great interest for a variety of catalysis and energy conversion applications, involving gas reactions and reforming. CuFe2O4 spinel is identified as a highly efficient fuel electrode for CO2/H2O co‐electrolysis due to its promising electrocatalytic activity. To identify the actual active sites, the electrochemical characteristics, composition, chemical state, and microstructure are systematically investigated while optimizing the electrolysis performance by varying the feed gas composition. Markedly enhanced electrolysis current density is achieved under a CO2‐enriched composition of 50%CO2/10%H2O‐Ar. This promising performance is attributed to the in situ exsolution of heterostructural "Cu/Fe3O4" nanoparticles on the parent CuFe2O4 surface during co‐electrolysis. Interestingly, a strong correlation of the electrolysis performance with the amount of the formed heterostructural cermet is observed. The exsolved cermet heterostructure plays a crucial role in CO2/H2O electroreduction, as also confirmed by density‐functional‐theory studies. The self‐exsolved Cu/Fe3O4 nanoparticles present exceptional strength due to a strong interaction between the formed metallic Cu and Fe3O4, enabling the electrode to remain active and stable under such high electrical polarization. The excellent durability and stability of the self‐exsolved heterostructural nanoparticles are clearly confirmed by long‐term operation at high‐working voltage with an outstanding Faradaic efficiency (nearly 100%). [ABSTRACT FROM AUTHOR]