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Corrosion behavior of (Cr2/3Ti1/3)3AlC2 and Ti3AlC2 in static oxygen‐saturated liquid lead–bismuth eutectic (LBE) at 550°C and (Cr2/3Ti1/3)3AlC2 in static oxygen‐depleted LBE at 500°C were investigated. In oxygen‐saturated corrosion, the loose and porous corrosion layer consisting of (PbTiO3 + TiO2) was generated on the surface of Ti3AlC2. In contrast, (Cr2/3Ti1/3)3AlC2 formed the protective Cr2O3 layer with better corrosion resistance. Moreover, dissolution corrosion of (Cr2/3Ti1/3)3AlC2 in oxygen‐depleted corrosion was intensified without a protective oxide film. And impurity phase TiC on the surface also caused the decomposition of matrix, thus impairing corrosion resistance. [ABSTRACT FROM AUTHOR]

Humic acid (HA) is the main precursor of carcinogenic compounds such as trichloromethane, which form during the disinfection of drinking water. Therefore, removing HA from water sources is crucial for producing safe drinking water. This study introduces a novel approach using dilute nitric acid as a nitrogen source to dope pristine Ti3AlC2 (TAC) to varying degrees, enhancing the material's photocatalytic degradation performance for HA. Characterisations through X‐ray diffraction, Fourier transform infrared, scanning electron microscopy, UV–vis and X‐ray photoelectron spectroscopy revealed that the surface morphology of the modified catalyst changed from an original blocky lamellar structure to a rod‐like cluster structure, which is advantageous for light trapping. In addition, the incorporation of nitrogen reduced the band gap of the material from 1.25 to 1.15 eV, considerably enhancing its overall light responsiveness and thereby improving its photocatalytic performance. The results demonstrated that the photocatalytic degradation efficiency of HA by TAC under optimal conditions reached 93.8 %, which is 4.3 times higher than the 21.8 % efficiency achieved using the undoped TAC material. The enhanced photocatalytic activity is attributed to N doping, which not only reduces the TiO2 band gap at the TAC surface but also improves the electrochemical behaviour of TAC. This results in enhanced light response and more efficient separation of photogenerated electron–hole pairs. The mechanism for CTAC–Nx photocatalytic degradation of HA was investigated using trapping agent experiments, revealing that the primary active substance responsible for the degradation is O2−. [ABSTRACT FROM AUTHOR]

With the marine industry's demands for carbon reduction and increased reliability, the friction and wear performance of marine engines is becoming increasingly important. MAX phase materials show great potential in marine engine tribopair materials due to their unique microstructure and performance. The typical MAX phase material Ti3AlC2 was combined with MoDTC and added to the lubricant containing ZDDP additive for the tribopair composed of chromium-based ceramic composite coated steel (CKS) piston rings and cast iron cylinder liners under impact-sliding conditions. Compared to Ti3AlC2 alone, the friction coefficient and wear depth of the designed composite additive MoDTC/Ti3AlC2 were reduced by 36.9% and 41.4%, respectively. The worn surface lubricated with the Ti3AlC2/MoDTC composite additive showed fewer scratches with significantly less plastic deformation and clearer honing grooves. The multi-component tribofilm containing FeS, MoS2, MoO3, ZnO, TiO2, Al2O3, unoxidised particles, short-chain phosphates, and some ZnS was present on the worn cylinder liner surface. The synergistic effect of Ti3AlC2, MoDTC and ZDDP additives in the lubricant can isolate the mutual contact, generate a solid tribofilm and reduce the scratching. This can provide some guidance for the development of high-performance lubricant additives under impact-sliding conditions. [ABSTRACT FROM AUTHOR]

Ti 3 AlC 2 was used as the additive to fabricate a novel (Zr 0 · 2 Ta 0 · 2 Nb 0.2 Hf 0.2 Mo 0.2)B 2 -based (HEBTAC) ceramic using spark plasma sintering at 1900 °C. The as-prepared HEBTAC ceramic sample consists of (Ti, Zr, Hf, Ta, Nb, Mo)B 2 , multiscale (Zr, Hf, Ta, Nb, Mo)C, and Al 2 O 3 phases, which are produced by the decomposition of Ti 3 AlC 2 and subsequent exchange reaction & solid solution reactions during the sintering process. The relative density, hardness, fracture toughness, and flexural strength of the HEBTAC ceramic sample are 99.43 %, 27.92 ± 1.87 GPa, 5.84 ± 0.14 MPa m1/2, and 629 ± 8.7 MPa, respectively, which are even better than the same class of high-entropy diboride ceramics previously published. Solid-solution strengthening, dislocation strengthening and nano-HEC strengthening existed in the ceramic sample contribute to its excellent mechanical properties. The in situ formed Al 2 O 3 and (Zr, Hf, Ta, Nb, Mo)C effectively enhances the toughness of the HEBTAC ceramic sample through the synergistic effect of intrinsic and extrinsic toughening. This study presents a new approach for reactive sintering densification of high-entropy diborides with both high strength and high toughness. [ABSTRACT FROM AUTHOR]

The exploration of unleaded free-cutting Cu40Zn brass with excellent mechanical and tribological properties has always drawn the attention of researchers. Due to its attractive properties combining metals and ceramics, Ti3AlC2 was added to Cu40Zn brass using high-energy milling and hot-pressing sintering. The effects of Ti3AlC2 on the microstructure, mechanical and tribological properties of Cu40Zn-Ti3AlC2 composites were studied. The results showed that Ti3AlC2 could suppress the formation of ZnO by adsorbing oxygen impurity and promote the formation of the β phase by releasing the β-forming element Al to the substrate. The hardness and wear resistance of Cu40Zn-Ti3AlC2 composites increased with increasing Ti3AlC2 content from 0 to 5 wt.%. The proper Ti3AlC2 additive was beneficial to both the strength and plasticity of the composites. The underlying mechanisms were discussed. [ABSTRACT FROM AUTHOR]

Defects such as interconnected pores and cracks can improve the abradability of ceramic-based abradable sealing coatings (ASCs) but may reduce the lifetime. Self-healing can potentially close cracks and transform interconnected pores into isolated ones through filling and sintering effects. Ti3AlC2 (TAC) was incorporated into LaMgAl11O19 (LMA) as both the self-healing agent and sintering aid, and plasma-sprayed LMA-based composite coatings were annealed at 1200 °C to assess their self-healing capabilities and then subjected to oxidation in air and corrosion in steam at 1300 °C to study their long-term stability. Results indicated that increasing TAC content significantly enhances self-healing effectiveness, evidenced by the closure of cracks and the isolation of pores. Oxidation and corrosion at 1300 °C led to significant grain growth and the formation of equiaxed grains with an aspect ratio of approximately 3, which may impair the toughening mechanism. Meanwhile, due to the preferential volatilization of Al in a steam environment, LTA decomposed into α-La2/3TiO3 and La4Ti3O12 phases, and the accelerated mass transfer also resulted in grain coarsening. Interestingly, the L20T composite coating with a porosity of 32.17 ± 0.94% and a hardness of 74.88 ± 1.55 HR15Y showed great potential for abradable applications due to its stable phase composition and uniform pore distribution. [ABSTRACT FROM AUTHOR]

MXene is a novel two-dimensional nano material with exceptional performance, which can be applied in the fields of energy storage structural materials, optics, catalysis, and sensors etc. However, its synthesis is a challenge to date. From the perspective of environmental friendliness, the method of Lewis salt etching can effectively avoid the use of dangerous reagents and has been seen as a pollution-free economic approach. In this article ZnCl 2 molten salt was chosen as corrosive agent to etch Ti 3 AlC 2 MAX phase and investigated the synthesis mechanism of Ti 3 C 2 Cl x MXene. The influence of main process factor, like raw materials, sintering temperature, and holding time on synthesis product were studied and discussed. The synthesis route was investigated by XRD and thermal analysis. SEM and TEM technology was used to analyze the microstructure and lattice of synthesis product. The results showed that the optimal process conditions: the molar ratio of raw materials was 1:6 (Ti 3 AlC 2 : ZnCl 2), the synthesis temperature and holding time were 600～700 °C and 4 h, respectively. Ti 3 C 2 Cl x MXene material prepared by this method has a complete layered structure and uniform composition, and its synthesis mechanism can be concluded to two steps: the first step was the reaction between Ti 3 AlC 2 MAX phase and ZnCl 2 to generate Ti 3 ZnC 2 MAX phase; In the second step, the Ti 3 ZnC 2 MAX phase reacted with the remaining ZnCl 2 to generate Ti 3 C 2 Cl x MXene material. [ABSTRACT FROM AUTHOR]

The development of new low‐carbon emission methods for the synthesis and processing of materials is an urgent task today. Here, we present a rapid, efficient, and low‐energy‐consuming synthesis method for high‐yield Ti3AlC2 MAX phase powders. Our method is based on induction heating‐assisted combustion synthesis (IH‐CS), where the heat of the reaction is used as a driving force of the process, and the conditions of the process are finely controlled using IH at the same time. Ti3AlC2 MAX phase was synthesized using TiC0.67 and Al powders as starting materials. The introduction of TiC0.67 reduced the total exothermic effect of the reaction, facilitating better control of the reaction process. IH was used to ignite the reaction and to hold the temperature after ignition at an optimal value to complete the synthesis process. The effects of holding temperature, Al, and Si addition on Ti3AlC2 yield were investigated. As a result, Ti3AlC2 MAX phase powders containing only.7 wt% of the secondary phase were synthesized in a very short time. Our findings suggest that IH‐CS is a highly effective and promising alternative for the facile fabrication of high‐purity MAX phase powders. [ABSTRACT FROM AUTHOR]

The damage mechanisms of Ti 3 AlC 2 ceramics during laser processing in air and water were studied using the pulsed laser. The focused high-energy laser induced the melting of surface of Ti 3 AlC 2 ceramics, causing the decomposition of Ti 3 AlC 2 into TiC and Al with Al rapidly evaporating. During the laser processing in the air, oxygen diffused inward to form a solid solution of TiC x O y , and the rapidly heating and cooling of resolidified layer generated high thermal tensile stresses to result in a large amount of microcracks. When processing in the water, the thermal stresses were greatly weakened, and the outward diffusion of Al steam resulted in the voids on the sample surface. Additionally, it is determined that after treating in the air and water, the residual flexural strengths of Ti 3 AlC 2 ceramics could retain the high values of 292 MPa and 484 MPa, and the Weibull moduli were kept at 7.2 and 16.0, respectively, exhibiting the excellent damage tolerance and high reliability. [ABSTRACT FROM AUTHOR]

The corrosion resistance of Ti 3 AlC 2 is an indispensable characteristic in its practical applications, and the focus of this study is to optimize its mechanical and corrosion properties by introducing metal ions at the M-sites of Ti 3 AlC 2. Utilizing Ti/Al/C/Zr/Mo/Cr powders, (Ti 0.8 X 0.2) 3 AlC 2 solid solutions were synthesized via reactive hot pressing, with XRD and SEM analyses confirming the formation of MAX phases. Results revealed varying degrees of influence on the properties of Ti 3 AlC 2 due to different doping elements. Among these, Zr-doped samples exhibited superior mechanical properties, boasting excellent hardness (511 Hv), flexural strength (386.57 MPa), and fracture toughness (10.24 MPa m1/2). Additionally, all (Ti 0.8 X 0.2) 3 AlC 2 samples formed n-type semiconductor passive layers in 3.5% NaCl solution, demonstrating outstanding corrosion resistance. Further investigation revealed that the enhancement in mechanical properties stems from solid solution strengthening and lattice distortion induced by different metallic elements. Meanwhile, the corrosion resistance is primarily attributed to alterations in electron distribution resulting from doping elements. These stable materials could find applications in electroplating wastewater treatment, where materials with excellent mechanical properties and corrosion resistance are required. It is anticipated that further modifications of MAX phase materials through doping will meet these additional requirements. [ABSTRACT FROM AUTHOR]

The monolithic PcBN composite tool materials were prepared at 5.5 GPa and 1450 ℃ with different contents of Ti3AlC2 as the binder phase. The effects of different mass fractions of Ti3AlC2 on the phase composition, microstructure, and mechanical properties of PcBN tool materials were studied. The results show that Ti3AlC2 can decompose completely to form TiC and Al-Ti alloys under high temperature and high pressure, and reacts with cBN to form AlN, TiB2, and TiC0.7N0.3 phases. TiC, AlN, TiB2, and TiC0.7N0.3 are uniformly distributed around the cBN and tightly bonded to the cBN, thereby improving the mechanical properties of PcBN. When the mass fraction of Ti3AlC2 is 25 %, the relative density, bending strength, fracture toughness, and wear ratio of PcBN reach the maximum values, which are 98.9%, 592 MPa, 6.87 MPa·m1/2and 7 350, respectively. When the mass fraction of Ti3AlC2 is 20%, the microhardness of PcBN reaches the maximum value of 4 786.7 HV.

Hydrazine is considered a powerful reducing agent and catalyst, showing diverse applications in agricultural industries, toxic degradation research, and wastewater management. Additionally, hydrazine can trigger some specific reactions when combined with suitable oxidants. Due to its highly polar nature, hydrazine can easily dissolve in alcohol, water, and various other polar solvents. Therefore, it can be extensively utilized in different areas of application and industries such as rocketry and various chemical applications. Despite its beneficial properties, hydrazine is unstable, posing significant risk due to its highly toxic nature. It is extremely hazardous to both human health and the environment. It can cause various illnesses and symptoms such as dizziness, temporary blindness, damage to the central nervous system, and even death when inhaled in sufficient quantities. Therefore, it is highly important to monitor the level of hydrazine to prevent its toxic and hazardous effects on human beings and the environment. In the present study, we discuss the simple fabrication of a disposable cost-effective and eco-friendly hydrazine sensor. We used a screen-printed carbon electrode, i.e., SPCE, as a base for the construction of a hydrazine sensor. The Ti3AlC2 MAX has been used as a suitable and efficient electrode material for the fabrication of disposable hydrazine sensors. We modified the active surface of the SPCE using a drop-casting approach. The resulting Ti3AlC2 MAX modified SPCE (Ti3AlC2@SPCE) has been utilized as an efficient and low-cost hydrazine sensor. Cyclic voltammetry, i.e., CV, and linear sweep voltammetry, viz., LSV, was employed as a sensing technique in this study. The optimization of pH and electrode material loading was conducted. The Ti3AlC2@SPCE exhibited excellent sensing performance toward hydrazine oxidation. A reasonable detection limit (0.01 µM) was achieved for hydrazine sensing. The fabricated sensor also demonstrated a reasonable linear range of 1–50 µM. This work provides the design and fabrication of simple disposable Ti3AlC2@SPCE as a suitable electrode for the determination of hydrazine using LSV technology. [ABSTRACT FROM AUTHOR]

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Among the various reinforcement phases available in Cu-based composites, the unique layered structure and easy diffusion of A-layer atoms make MAX phases more suitable for reinforcing a copper matrix than others. In this study, Cu-coated Ti3AlC2 particles (Cu@Ti3AlC2) were prepared through electroless plating, and Cu@Ti3AlC2/Cu composites were fabricated via vacuum hot-press sintering. The phase composition and microstructure of both Cu@Ti3AlC2 powder and composites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results demonstrate the creation of successful electroless copper plating to obtain a Cu coating on Ti3AlC2 particles. At 850 °C, a small amount of Ti3AlC2 particles decompose to form TiCx, while Al atoms from the A layer of MAX phase diffuse into the Cu matrix to form a solid solution with Cu(Al). The test results reveal that the density of the Cu@Ti3AlC2/Cu composite reaches 98.5%, with a maximum compressive strength of 705 MPa, which is 8.29% higher than that of the Ti3AlC2/Cu composite. Additionally, the compressive strain reaches 37.6%, representing an increase of 12.24% compared to that exhibited by the Ti3AlC2/Cu composite. [ABSTRACT FROM AUTHOR]

In this work, the ablation behaviors of Ti 3 AlC 2 ceramics were investigated in a nitrogen plasma flame at various temperatures. The ablation mechanisms were determined by analyzing phase compositions, macroscopic morphology, and microstructure. As the ablation temperature increased from 1500 to 1900°C, the linear ablation rate increased from − 0.725–8.7 µm/s, while the mass ablation rate increased from− 0.095–2.103 mg/s. At the ablation temperatures below 1900 °C, an oxide layer mainly consisting of Al 2 TiO 5 was formed on the ablated surface owing to the decomposition and oxidation of Ti 3 AlC 2 , which adequately protected the matrix. When the ablation temperature reached 1900 °C, the oxide layer melted and was blown away by the plasma flow, resulting in the loss of protection and the rapid increase in ablation rates. The results indicate that Ti 3 AlC 2 ceramic exhibits excellent ablation resistance below 1900 °C and is potentially used as thermal protection material. [ABSTRACT FROM AUTHOR]

Herein, we report a simple electrochemical method to exfoliate the Ti3AlC2 MAX phase and also investigate the Al3+ ion storage phenomenon in aqueous electrolyte. The exfoliation process avoids the harmful Hydrofluoric acid, which is often used for the processing of MXenes. It is demonstrated that exfoliation could be achieved when a hybrid aqueous electrolyte was utilized for the electrochemical treatment of Ti3AlC2. Additionally, porous surface structure could also be noticed. The electrolyte is an aqueous mixture of 1 M AlCl3 and 5 M NaOH (1:10 v/v). The exfoliation was evidenced by electron microscopy images, XRD patterns and Raman spectra. The Al3+ ion storage behaviour is also demonstrated in the exfoliated MAX phase. It was revealed that kinetics is governed by a diffusion-controlled process. [ABSTRACT FROM AUTHOR]

Herein, we report a simple electrochemical method to exfoliate the Ti3AlC2 MAX phase and also investigate the Al3+ ion storage phenomenon in aqueous electrolyte. The exfoliation process avoids the harmful Hydrofluoric acid, which is often used for the processing of MXenes. It is demonstrated that exfoliation could be achieved when a hybrid aqueous electrolyte was utilized for the electrochemical treatment of Ti3AlC2. Additionally, porous surface structure could also be noticed. The electrolyte is an aqueous mixture of 1 M AlCl3 and 5 M NaOH (1:10 v/v). The exfoliation was evidenced by electron microscopy images, XRD patterns and Raman spectra. The Al3+ ion storage behaviour is also demonstrated in the exfoliated MAX phase. It was revealed that kinetics is governed by a diffusion-controlled process. [ABSTRACT FROM AUTHOR]

With the marine industry’s demands for carbon reduction and increased reliability, the friction and wear performance of marine engines is becoming increasingly important. MAX phase materials show great potential in marine engine tribopair materials due to their unique microstructure and performance. The typical MAX phase material Ti3AlC2 was combined with MoDTC and added to the lubricant containing ZDDP additive for the tribopair composed of chromium-based ceramic composite coated steel (CKS) piston rings and cast iron cylinder liners under impact-sliding conditions. Compared to Ti3AlC2 alone, the friction coefficient and wear depth of the designed composite additive MoDTC/Ti3AlC2 were reduced by 36.9% and 41.4%, respectively. The worn surface lubricated with the Ti3AlC2/MoDTC composite additive showed fewer scratches with significantly less plastic deformation and clearer honing grooves. The multi-component tribofilm containing FeS, MoS2, MoO3, ZnO, TiO2, Al2O3, unoxidised particles, short-chain phosphates, and some ZnS was present on the worn cylinder liner surface. The synergistic effect of Ti3AlC2, MoDTC and ZDDP additives in the lubricant can isolate the mutual contact, generate a solid tribofilm and reduce the scratching. This can provide some guidance for the development of high-performance lubricant additives under impact-sliding conditions.

This article considers the main stages of synthesis Ti3SiC2 and Ti3AlC2 and describes in detail the methods of obtaining these materials. Physical and mechanical properties of materials are investigated. The possibility of using materials in the field of nuclear waste management is considered. [ABSTRACT FROM AUTHOR]

Ti3AlC2 ceramic was produced using a 3Ti–Al–1.8C powder mixture by reactive hot pressing at 2–10 MPa and 1100°C–1300°C for 15–60 min. X‐ray diffraction patterns confirmed the Ti2AlC phase up to 1200°C, and at 1300°C, Ti3AlC2 remained as a primary phase with a tiny peak of TiC. Ti3AlC2 and TiC phases varied from 93 to 96 vol.% and 7 to 4 vol.%, respectively, with different pressure and time at 1300°C. An applied pressure of 10 MPa and 1300°C resulted in a density of 4.18 g/cm3 (98.4% relative density) in the samples. It was observed that lower temperature (1100–1200°C) and low applied pressure (2 MPa) do not attain the required density, whereas soaking time is insignificant to achieve the required density at 1300°C. The microhardness and flexural strength were 6.32 ±.20 GPa and 592 ± 42 MPa, respectively. [ABSTRACT FROM AUTHOR]

Doping can introduce diverse interfaces and optimize impedance matching, making it a significant approach for enhancing the substrate's microwave absorption performance (MAP). Herein, a novel Ni-doped Ti 3 AlC 2 composite (x Ni-Ti 3 AlC 2 ; x = 0, 0.1, 0.2, 0.3) is successfully fabricated using pressureless sintering method. Partial replacement of Al atoms with doped Ni atoms leads to an improvement in permeability. Simultaneously, the substitution of Ni for Al and the formation of metal oxides (such as Al 2 O 3 , NiO, etc.) weaken the construction of conductive network, resulting in reduced conductivity and permittivity. The magnetic-dielectric synergistic effect significantly improves the impedance matching of Ti 3 AlC 2. Furthermore, the presence of multiphase interfaces and heightened defects results in an augmentation of both interfacial polarization and dipole polarization. Consequently, the 0.2Ni-Ti 3 AlC 2 demonstrates an outstanding MAP, with a minimum reflection loss (RL min) of -48.73 dB at 14.33 GHz and an effective absorption bandwidth (reflection loss < -10 dB) of 4.38 GHz (11.43-15.81 GHz) at a thickness of 1.72 mm, surpassing that of Ti 3 AlC 2. Moreover, the 0.1Ni-Ti 3 AlC 2 achieves a RL min of -65.07 dB, which is 4.24 times that of Ti 3 AlC 2. This study provides a valuable reference for assisting in the design and development of an absorber that capitalizes on magnetic-dielectric synergistic effect. [ABSTRACT FROM AUTHOR]

The MAX phase is a material with excellent electrical and thermal conductivity and thermal shock and oxidation resistance owing to its metallike bonding properties. The impurities in the Ti3AlC2 MAX phase must be controlled because the oxides and TiC derived from the synthesis process remain in MXene and markedly affect the electrical conductivity and chemical stability. This study investigated whether the Ti3AlC2 MAX phase can be synthesized from titanium powder prepared from low‐cost titanium scrap by hydrogenation–dehydrogenation (HDH) and deoxidation in the solid‐state (DOSS) processes. Almost single‐phase Ti3AlC2 MAX phase was obtained by synthesis at 1450°C for 5 h. The oxygen concentrations of the HDH‐MAX and DOSS‐MAX powders (25–45 μm) were 7215 and 3875 ppm, respectively. Oxygen reduction of titanium powder through DOSS can help improve the purity of Ti3AlC2 MAX phase by minimizing the imbalance in the stoichiometric ratio during synthesis. The HDH‐MAX and DOSS‐MAX powders prepared from titanium scrap displayed a higher Ti3AlC2 phase fraction and lower oxygen concentration than those of commercial Ti3AlC2 MAX phase powders. This cost reduction and purity improvement will increase the accessibility of the Ti3AlC2 MAX phase, supporting further research into its applications. [ABSTRACT FROM AUTHOR]

The exploration of unleaded free-cutting Cu40Zn brass with excellent mechanical and tribological properties has always drawn the attention of researchers. Due to its attractive properties combining metals and ceramics, Ti3AlC2 was added to Cu40Zn brass using high-energy milling and hot-pressing sintering. The effects of Ti3AlC2 on the microstructure, mechanical and tribological properties of Cu40Zn-Ti3AlC2 composites were studied. The results showed that Ti3AlC2 could suppress the formation of ZnO by adsorbing oxygen impurity and promote the formation of the β phase by releasing the β-forming element Al to the substrate. The hardness and wear resistance of Cu40Zn-Ti3AlC2 composites increased with increasing Ti3AlC2 content from 0 to 5 wt.%. The proper Ti3AlC2 additive was beneficial to both the strength and plasticity of the composites. The underlying mechanisms were discussed.

Ti 3 AlC 2 as a typical MAX phase has attracted extensive attention due to its advantages of both metals and ceramics. However, the decomposition of Ti 3 AlC 2 during pressureless sintering leads to a low density, which restricts its application in complex-shaped components. To address this challenge, MgO, CeO 2 , Y 2 O 3 , and La 2 O 3 were employed as additives to fabricate Ti 3 AlC 2 ceramics with minimal decomposition via pressureless sintering. It was observed that these oxide additives reacted with aluminum and oxygen, forming MgAl 2 O 4 , CeAlO 3 , YAlO 3 , and LaAlO 3 , respectively. These in-situ generated aluminate particles effectively impeded the outward diffusion of aluminum and the inward diffusion of oxygen, thereby inhibiting the decomposition of Ti 3 AlC 2. Furthermore, the thermal expansion mismatch between the in-situ generated particles and the matrix induced beneficial residual stresses. These combined effects contributed to the synchronized enhancement of both strength and toughness. Among the four additives, CeO 2 displayed the best efficiency. Ti 3 AlC 2 -1.0 wt%CeO 2 reached a flexural strength of 680.74 MPa and fracture toughness of 7.82 MPa m1/2, equivalent to those by pressure assisted sintering. The calculated toughness considering the residual stress was approximately 7.71 MPa m1/2, in good agreement with the measured value. [ABSTRACT FROM AUTHOR]

Azithromycin (AZY) is a well-known top-prioritized antibiotic and is used by humans in strong concentrations. However, the side effects of the AZY antibiotic may cause some serious and significant damage to humans and the environment. Thus, there is a need to develop effective and sensitive sensors to monitor accurate concentrations of AZY. In the last decade, electrochemistry-based sensors have received enormous attention from the scientific community because of their high sensitivity, selectivity, cost-effectiveness, fast response, rapid detection response, simple fabrication, and working principle. It is important to mention that electrochemical sensors rely on the properties of electrode modifiers. Hence, the selection of electrode materials is of great significance when designing and developing efficient and robust electrochemical sensors. In this study, we fabricated an AZY sensor by utilizing a molybdenum disulfide/titanium aluminum carbide (MoS2@Ti3AlC2) composite as the electrode material. The MoS2@Ti3AlC2 composite was synthesized via a simple sonication process. The synthesized MoS2@Ti3AlC2 composite was characterized using a powder X-ray diffraction (XRD) method to examine the phase purity and formation of the MoS2@Ti3AlC2 composite. Scanning electron microscopy (SEM) was used to study the surface morphological features of the prepared MoS2@Ti3AlC2 composite, whereas energy dispersive X-ray spectroscopy (EDAX) was adopted to determine the elemental composition of the prepared MoS2@Ti3AlC2 composite. The glassy carbon (GC) electrode was modified with the prepared MoS2@Ti3AlC2 composite and applied as the AZY sensor. The sensing performance of the MoS2@Ti3AlC2 composite-modified GC electrode was studied using linear sweep voltammetry. The sensor demonstrated excellent performance when determining AZY and showed a good detection limit of 0.009 µM with a sensitivity of 6.77 µA/µM.cm2. [ABSTRACT FROM AUTHOR]

MAX phase, as a group of layered ternary carbides and nitrides exhibiting combined properties of metallic and ceramic materials, attracts increasing interest because they own exceptionally chemical, physical, electrical, thermal, and mechanical properties. In the present paper, a novel Ti3AlC2-based green part was manufactured by extrusion-based fused filament fabrication (FFF) and 3D printing technologies. The morphology, thermal/electrical conductivity, thermal stability, electromagnetic interference (EMI) shielding effectiveness (SE), and mechanical properties of Ti3AlC2/binder with the volume ratio of 1:1 were investigated. The tensile and compressive strengths and elongation are measured to be 8.29 MPa and 18.20%, 44.90 MPa and 33.76%, respectively. The morphology of the filament reveals that Ti3AlC2 powders are well bonded by the thermoplastic binder. More importantly, the composite shows good thermal and electrical conductivities together with the excellent EMI shielding effectiveness, which is of great potential in the practical applications as conductor, heat dissipating, anti-static, and EMI shielding materials. The successful fabrication of Ti3AlC2-based composites via FFF-based 3D printing technology is beneficial to develop other MAX phase products with complex geometries and additional functionalities. [ABSTRACT FROM AUTHOR]

Currently, materials that absorb electromagnetic waves (EMW) are being increasingly studied and used. In particular, numerous attempts have been made to improve the performance of EMW-absorbing ceramics, but little attention was paid to the effect of doping on their relevant properties. In this work, Ti 3 AlC 2 , a typical MAX-phase ceramic, was doped with different elements (Zr, Mo, Cr, Fe and Ni) at the M site via a pressure-free reactive sintering. Phase and microstructure analysis show that the doped Ti 3 AlC 2 samples possess high purities and typical layered structures. It was noticed that (Ti 0.8 Zr 0.2) 3 AlC 2 demonstrates the lowest reflection loss (−48.0 dB at the thickness of 1.62 mm) and a maximum effective absorption bandwidth of 3.9 GHz. Elemental doping has been proved to alter the dielectric and magnetic properties of Ti 3 AlC 2 , and the boosted EMW absorption performance was found to be originated from the improved impedance matching. Here, we systematically investigated the influence of different dopants on the EMW absorption characteristics of Ti 3 AlC 2 , which provides significant insights for the future design of novel EMW-absorbing materials. [ABSTRACT FROM AUTHOR]

Poor high-temperature stability (HTS) and weak microwave absorption performance (MAP) are a major restriction for wave-absorbing materials in elevated temperature ambient. Consequently, the Stöber process and the sol–gel method are first devised and used to create multi-core/shell SiO2@Al2O3 nanostructures (MCSNs) on Ti3AlC2 (TAC). The MCSNs with a thickness of 135–215 nm raise the starting oxidation temperature of the matrix by 400°C. Furthermore, the weight gain drops from 17.44 to 2.32% within 1 h at 800°C. The effective absorption bandwidth with a reflection loss (RL) ≤ −10 dB of the MCSNs-coated TAC is 3.25 GHz (8.68–11.27 and 11.63–12.29 GHz) at a thickness of 2.0 mm, which is 4.7 times that of the matrix. The minimum RL is reduced by a factor of 2.77 from −10.68 to −29.55 dB. The enhanced MAP is due to the introduced multiple reflection events and scattering mechanism as well as the enhanced electronic polarization, interface polarization, and polarization relaxation. The growth of the MCSNs provides a reference for the design and preparation of bifunctional materials with good HTS and MAP.

Hydrazine is considered a powerful reducing agent and catalyst, showing diverse applications in agricultural industries, toxic degradation research, and wastewater management. Additionally, hydrazine can trigger some specific reactions when combined with suitable oxidants. Due to its highly polar nature, hydrazine can easily dissolve in alcohol, water, and various other polar solvents. Therefore, it can be extensively utilized in different areas of application and industries such as rocketry and various chemical applications. Despite its beneficial properties, hydrazine is unstable, posing significant risk due to its highly toxic nature. It is extremely hazardous to both human health and the environment. It can cause various illnesses and symptoms such as dizziness, temporary blindness, damage to the central nervous system, and even death when inhaled in sufficient quantities. Therefore, it is highly important to monitor the level of hydrazine to prevent its toxic and hazardous effects on human beings and the environment. In the present study, we discuss the simple fabrication of a disposable cost-effective and eco-friendly hydrazine sensor. We used a screen-printed carbon electrode, i.e., SPCE, as a base for the construction of a hydrazine sensor. The Ti3AlC2 MAX has been used as a suitable and efficient electrode material for the fabrication of disposable hydrazine sensors. We modified the active surface of the SPCE using a drop-casting approach. The resulting Ti3AlC2 MAX modified SPCE (Ti3AlC2@SPCE) has been utilized as an efficient and low-cost hydrazine sensor. Cyclic voltammetry, i.e., CV, and linear sweep voltammetry, viz., LSV, was employed as a sensing technique in this study. The optimization of pH and electrode material loading was conducted. The Ti3AlC2@SPCE exhibited excellent sensing performance toward hydrazine oxidation. A reasonable detection limit (0.01 µM) was achieved for hydrazine sensing. The fabricated sensor also demonstrated a reasonable linear range of 1–50 µM. This work provides the design and fabrication of simple disposable Ti3AlC2@SPCE as a suitable electrode for the determination of hydrazine using LSV technology.

Two-dimensional transition metal carbides (MXenes) are widely used in the field of electrochemical energy storage due to their unique properties, but the efficient use of multilayer MXenes (m-MXenes) to prepare flexible electrodes remains a challenge. Herein, large-size graphene oxide (GO) is used as a conductive adhesive to bridge the multilayer Ti3C2Tx (m-Ti3C2Tx) to form a Ti–O-C bond to form the flexible Ti3C2Tx/GO (MG) film which was subsequently implanted by nitrogen ions to dope nitrogen in its surface layers (N-Ti3C2Tx/GO, NMG). The NMG was annealed at 400 ℃ to obtain the N-Ti3C2Tx/reduced GO (N-Ti3C2Tx/rGO, NMRG) electrode for supercapacitor. Compared with the Ti3C2Tx/rGO (MRG), the specific capacitance of NMRG-1 (nitrogen ion implantation dose is 1 × 1017) reaches 115 F g−1 (248. 7 F cm−3) at 0.2A g−1, while it is 95 F g−1 (167.8 F cm−3) of MRG. The rate performance of NMRG-1 is increased from 31.5 (MRG) to 76.1%. In addition, NMRG-1 electrode can maintain 73% capacitance retention and 85% Coulomb efficiency after 10,000 cycles at 2A g−1. And it exhibits energy density of 8.6 Wh L−1 at power density of 122.4W L−1. The results show that ion implantation provides a selective method for nitrogen doping in multilayer MXene, making it more competitive in practical applications. [ABSTRACT FROM AUTHOR]

Ti3AlC2–Al cermets were produced by a new method combining SHS and spontaneous infiltration. SHS was applied to obtain a ceramic Ti3AlC2 MAX phase with a porous structure, which in the hot state was brought into contact with Al melt and Al-based melts for spontaneous high-temperature infiltration. The optimum time delay between the end of combustion and the start of infiltration with melt was found to be 7–8 s. This time pause was shown to be enough to complete the structure formation of MAX phase in the porous skeleton and to spontaneously infiltrate the pores with melt. Upon infiltration with pure Al melt, Ti3AlC2 MAX-phase was shown to completely decompose to TiC and TiAl3. The presence of 12% Si or 32% Cu in Al melt contributed to the partial retention of Ti3AlC2 in SHS cermet. It was found that the yield stress of cermets obtained by infiltration of SHS skeleton with Al–12% Si melt is 410 MPa that exceeds that for pure Al–12% Si alloy (~260 MPa) by approximately 58%. [ABSTRACT FROM AUTHOR]

Among the various reinforcement phases available in Cu-based composites, the unique layered structure and easy diffusion of A-layer atoms make MAX phases more suitable for reinforcing a copper matrix than others. In this study, Cu-coated Ti3AlC2 particles (Cu@Ti3AlC2) were prepared through electroless plating, and Cu@Ti3AlC2/Cu composites were fabricated via vacuum hot-press sintering. The phase composition and microstructure of both Cu@Ti3AlC2 powder and composites were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results demonstrate the creation of successful electroless copper plating to obtain a Cu coating on Ti3AlC2 particles. At 850 °C, a small amount of Ti3AlC2 particles decompose to form TiCx, while Al atoms from the A layer of MAX phase diffuse into the Cu matrix to form a solid solution with Cu(Al). The test results reveal that the density of the Cu@Ti3AlC2/Cu composite reaches 98.5%, with a maximum compressive strength of 705 MPa, which is 8.29% higher than that of the Ti3AlC2/Cu composite. Additionally, the compressive strain reaches 37.6%, representing an increase of 12.24% compared to that exhibited by the Ti3AlC2/Cu composite.

In this work, 2024Al matrix composite reinforced by in-situ Al3Ti and TiC was fabricated using hot-press sintering Ti3AlC2 and 2024Al powders. The effect of Ti3AlC2 precursor additions (10, 20 and 30 vol.%) on microstructure and mechanical properties of Al3Ti-TiC/2024Al composites were investigated. It was found that Ti3AlC2 decomposed into submicron TiC particles at 950 °C, while Al atoms reacted with Ti to form Al3Ti. In-situ Al3Ti and submicron TiC were homogeneously distributed in 2024Al matrix. The high temperature tensile and compressive behavior of the in-situ Al3Ti-TiC/2024Al composites was tested in the temperature range of 25–400 °C. The results indicated that the tensile and compressive properties of the material showed temperature dependence. The 20 vol.% Ti3AlC2/2024Al composite exhibit a higher tensile yield strength of 368 MPa with a noticeable elongation of 5.4% at room temperature compared to the pure 2024Al (tensile yield strength is 146 MPa with elongation of 8.5%). At 300 and 400 °C, the tensile yield strength of the as-sintered 30 vol.% Ti3AlC2/2024Al composite was determined to be 176 and 126 MPa, increased by 96% and 293%, respectively, compared with that of pure 2024Al alloy. The excellent tensile property of Al3Ti-TiC/2024Al composites can be ascribed to the synergistic strengthening effect in term of dislocation density, load transfer and dispersion strengthening.

Al2O3–C refractories are potential candidates for use in gasifiers, and they are Cr2O3‐free. However, the oxidation of the carbon species and ceramic phases within the high‐temperature water vapor environment may deteriorate the integrity of the working lining. Ti3AlC2 has been verified as an effective antioxidant for Al2O3–C refractories in air. In this study, the structural transformation of Ti3AlC2 during heat treatment and the water vapor resistance of Ti3AlC2‐containing Al2O3–C refractories are investigated. The results show that the oxidation of Ti3AlC2 and Si in the matrix contributes to the in situ formation of a multilayer core–shell structure of TiC–AlTi2O5–Al6Si2O13. These structural evolutions improve densification and stimulate pore size refinement, which enhances the mechanical properties and thermal stress resistance of the specimens. In particular, the refined pore size contributes to the significantly improved water vapor resistance at high temperatures. [ABSTRACT FROM AUTHOR]

Microarc oxidation (MAO) layers were prepared using 8g/L Na2SiO3 + 6g/L (NaPO3)6 + 4g/L Na2WO4 electrolyte with the addition of 2g/L Ti3SiC2/Ti3AlC2 particles under constant-current mode. The roughness, porosity, composition, surface/cross-sectional morphology, and frictional behavior of the prepared MAO layers were characterized by 3D real-color electron microscopy, scanning electron microscopy, X-ray energy spectrometry, X-ray diffractometry, and with a tribo-tester. The results showed that the addition of Ti3SiC2 and Ti3AlC2 to the electrolyte reduced the porosity of the prepared layers by 9% compared with that of the MAO layer without added particles. The addition of Ti3SiC2/Ti3AlC2 also reduced the friction coefficient and wear rate of the prepared layers by 35% compared with that of the MAO layer without added particles. It was found that the addition of Ti3AlC2 particles to the electrolyte resulted in the lowest porosity and the lowest wear volume. [ABSTRACT FROM AUTHOR]

The phase transitions and He bubble evolution in Ti 3 AlC 2 with the sequential He ions implantation and Fe ions irradiation at room temperature were investigated with grazing incidence X-ray diffraction and transmission electron microscopy. The pre-implanted He makes an obviously effect of suppressing the phase transitions caused by the following Fe ions irradiation. The following Fe ions irradiation was also found to create a competitive effect on the evolution of the pre-formed He bubbles. It can cause not only the growth of He bubbles, but the shrinkage (or re-solution of He bubbles). This will improve the resistance to He bubbles induced damage for Ti 3 AlC 2. Both He ions implantation and Fe ions irradiation actually inhibit each other's irradiation damage to the material. This may play a positive role in reducing irradiation damage to the Ti 3 AlC 2 material, and also provides new insight into irradiation resistance of this material. [ABSTRACT FROM AUTHOR]

In the present study, a biomimetic strategy concerning to surmount the predicament of strength-toughness tradeoff in the Ni matrix composite was carried out. By assembling Ti 3 AlC 2 -based preceramic papers with pure Ni foils alternatively, a novel kind of in-situ TiC/Ni-Ni 3 (Al,Ti) composite with a mimicking nacre architecture was successfully fabricated. The results show that the grain gradient of in-situ TiC combined with γ'-Ni 3 (Al,Ti) was generated in the composite layer and alloy layer, respectively. The interlayer interface was well-bonded without microvoids, flaws, or other defects. Ascribed to an excellent combination of hard-soft laminate architecture, grain gradient as well as superior interfacial bonding, a synergy of mechanical strength and toughness in the laminated TiC/Ni-Ni 3 (Al,Ti) composites was achieved. The Vickers hardness increases gradually along alloy layer, interface, and composite layer. The flexural strength and fracture toughness were ∼18 % and ∼92 % higher than the counterpart of homogeneous TiC/Ni-Ni 3 (Al,Ti) composite. The laminated architecture enhances the efficiencies of gradient TiC grains in mechanical strengthening for required bearing and loading transmission, and toughens composite materials by interfacial delamination, cracks deflection, bridging and blunting. • Inspired by natural nacre, an in-situ laminated Ni matrix composite was successfully fabricated. • Grain gradient of TiC and Ni 3 (Al,Ti) appears in composite and alloy layers, respectively. • Gradient interface was built through mutual diffusion of Ni-Al-Ti atoms. • Laminated TiC/Ni-Ni 3 (Al,Ti) composite shows excellent combination of strength and toughness. [ABSTRACT FROM AUTHOR]

Brazing of Zircaloy-4 (Zr-4) to Ti 3 AlC 2 ceramic was investigated using a Ti–13Zr–21Cu–9Ni (wt.%) amorphous braze alloy (ABA) at temperatures ranging from 840 °C to 990 °C for 5 min. The interfacial reactions of the brazed joint were comprehensively analyzed, revealing a distinct multilayer structure consisting of Ti 3 AlC 2 /ZrC/α-Zr(Ti) + [Zr(Ti)] 2 Cu + [Zr(Ti)] 2 [Cu(Ni)]/α-Zr(Ti)/α-Zr. The formation of the ZrC carbide particle layer primarily results from the reaction between the molten ABA and decomposed Ti 3 AlC 2 caused by the de-intercalation of Al. Additionally, the dissolution of Zr-4 into the ABA induces an alteration in the composition of the Zr-4/ABA interface, leading to the formation of α-Zr(Ti) isothermal solidification dendrites. The effect of brazing temperature on the mechanical properties of the joint was investigated and detailed fracture analysis was conducted to determine the failure mechanism. The fracture path result indicated that the joint primarily fractured within the ZrC layer due to the mismatch of hardness, rather than within the reticular [Zr(Ti)] 2 [Cu(Ni)] segregation phase. The maximum shear strength of the brazed Ti 3 AlC 2 /Zr-4 joint with an average strength of 187 ± 34 MPa was achieved by brazing at 930 °C for just 5 min. With the increase in brazing temperature, the thickness of the ZrC ceramic layer became thicker in an undulating manner, and the content of Zr-based alloy particles in the ZrC layer increased gradually, resulting in a slight decrease in the bearing capacity of the joint. The presented results provide valuable insights into the microstructural evolution, interfacial reactions, and mechanical properties of the Ti 3 AlC 2 /Zr-4 brazed joints using amorphous alloys. [Display omitted] • Brazing of Ti 3 AlC 2 to Zr-4 was studied with an amorphous alloy for the first time. • The joint consists of Ti 3 AlC 2 /ZrC/Zr(Ti) + [Zr(Ti)] 2 Cu + [Zr(Ti)] 2 [Cu(Ni)]/Zr(Ti)/Zr. • The maximum shear strength of the Ti 3 AlC 2 /Zr-4 brazed joint reached 187 MPa. • Cracks in ZrC had never propagated straightly but were highly deflected. [ABSTRACT FROM AUTHOR]

[Display omitted] • A Ti-Al-C MAX phase (Ti 3 AlC 2) is used to recover gold from acidic solutions. • High gold extraction capacity (>6000 mg/g) is achieved at pH < 1. • High selectivity for gold is observed in the presence of interfering metal ions. • Gold recovery is likely to proceed via a reduction reaction similar to cementation. • High purity gold (92 mass%) is recovered without any posttreatment. Given the scarcity of natural gold sources and associated mining challenges, the recovery of gold from secondary sources, such as electronic equipment waste (e-waste), becomes imperative. E-waste is typically treated with aqua regia to obtain highly acidic gold-containing solutions, which are subsequently processed by various methods to recover gold. Gold recovery materials offer numerous benefits but often exhibit insufficient selectivity, efficiency, and cost-effectiveness. To address this problem, we herein used a nonmodified pristine Ti-Al-C MAX phase (Ti 3 AlC 2) to realize the one-pot room-temperature recovery of gold from highly acidic solutions (pH < 1) in the form of easily collectable bulky ball-shaped Au0 aggregates. High gold selectivity (K d = 2.03 × 106 mL/g) and extraction efficiency (∼99 %) were observed even in the presence of interfering metal ions (Pd2+, Pt4+, Co2+, Ni2+, Cu2+, Zn2+), and the maximum gold extraction capacity (>6000 mg/g) surpassed that of previously reported gold recovery materials. The recovered gold was highly pure (>90 mass%) and contained minimal amounts of the original MAX phase, which obviated the need for intensive postpurification. The results of instrumental analyses suggested that gold recovery relied on electron transfer, similar to cementation, and primarily involved the reduction of solution-phase Au3+ to Au0 via electron transfer from the Ti and Al of Ti 3 AlC 2. Thus, our work demonstrates the significant potential of pristine Ti 3 AlC 2 for the energy-efficient recovery of gold from highly acidic solutions and paves the way for the efficient valorization of e-waste. [ABSTRACT FROM AUTHOR]

The present paper set out to investigate the synthesis and electromagnetic characterization of Ti 3 AlC 2 MAX phase and Ti 3 C 2 T x MXene in Ti–Al–C ternary system. In this regard, Ti 3 AlC 2 MAX phase was synthesized using mechanical milling process of TiC, Al, and Ti powder mixtures based on 2TiC–Al–Ti + xAl (x = 0, 0.25, 0.5, 0.75 and 1). The HF acidic etching was also employed to synthesize the Ti 3 C 2 T x MXene. Structural and electromagnetic characterizations of the prepared samples were conducted using X-ray diffraction (XRD), scanning electron microscopy (SEM) and vector network analyzer. The obtained results point to the impossibility of the formation of Ti 3 AlC 2 single-phase structure in stoichiometric system. In other word, development of the Ti 3 AlC 2 single-phase structure is only possible in non-stoichiometric 2TiC–2Al–Ti system. The minimum reflection losses of the prepared Ti 3 AlC 2 MAX phase was estimated to be around −30.73 dB at the matching frequency of 15.25 GHz. The results further revealed that the etching time affects electromagnetic behavior of the MXene. That is, an increase in the etching time brings about a change in the reflection loss (RL) from −24.17 to −5.69 dB within the frequency range of 1–18 GHz. • Successfully synthesis of Ti 3 AlC 2 MAX and Ti 3 C 2 T x MXene in Ti–Al–C ternary system. • The phase transformation in 2TiC–Al–Ti + xAl powder mixtures has been investigated. • The electromagnetic characteristics of Ti 3 AlC 2 and Ti 3 C 2 T x has been studied. [ABSTRACT FROM AUTHOR]

Azithromycin (AZY) is a well-known top-prioritized antibiotic and is used by humans in strong concentrations. However, the side effects of the AZY antibiotic may cause some serious and significant damage to humans and the environment. Thus, there is a need to develop effective and sensitive sensors to monitor accurate concentrations of AZY. In the last decade, electrochemistry-based sensors have received enormous attention from the scientific community because of their high sensitivity, selectivity, cost-effectiveness, fast response, rapid detection response, simple fabrication, and working principle. It is important to mention that electrochemical sensors rely on the properties of electrode modifiers. Hence, the selection of electrode materials is of great significance when designing and developing efficient and robust electrochemical sensors. In this study, we fabricated an AZY sensor by utilizing a molybdenum disulfide/titanium aluminum carbide (MoS2@Ti3AlC2) composite as the electrode material. The MoS2@Ti3AlC2 composite was synthesized via a simple sonication process. The synthesized MoS2@Ti3AlC2 composite was characterized using a powder X-ray diffraction (XRD) method to examine the phase purity and formation of the MoS2@Ti3AlC2 composite. Scanning electron microscopy (SEM) was used to study the surface morphological features of the prepared MoS2@Ti3AlC2 composite, whereas energy dispersive X-ray spectroscopy (EDAX) was adopted to determine the elemental composition of the prepared MoS2@Ti3AlC2 composite. The glassy carbon (GC) electrode was modified with the prepared MoS2@Ti3AlC2 composite and applied as the AZY sensor. The sensing performance of the MoS2@Ti3AlC2 composite-modified GC electrode was studied using linear sweep voltammetry. The sensor demonstrated excellent performance when determining AZY and showed a good detection limit of 0.009 µM with a sensitivity of 6.77 µA/µM.cm2.

In the present work, a textured Ti 3 AlC 2 /TiAl 3 /Al composite with anisotropic microstructures and properties was successfully prepared by combining multistep ball-milling, flaky powder self-assembly, spark plasma sintering (SPS), and in-situ reaction. The effects of phase constitution and crystallographic orientation on anisotropic strengthening and fracture mechanisms of the composite were discussed. The results show that the preferred orientation of Ti 3 AlC 2 flakes was achieved during densification with the Lotgering orientation factor of the textured top surface (TTS) of 0.58. The high surface energy of Ti 3 AlC 2 submicron flakes provided the driving force for the low-temperature in-situ formation of TiAl 3. The in-situ formed TiAl 3 further improved the strength of the composite. The// c -axis samples achieved a high flexural strength of 565.9 MPa. The analysis of the flexural fracture surfaces shows that the fracture modes of Ti 3 AlC 2 flakes include basal plane cleavage, delamination, kinking, particle pull-out, and prismatic plane fracture, which in turn affects the toughness of the samples with different loading directions. Particle pull-out of the Ti 3 AlC 2 flakes is the primary mechanism to improve the toughness. This novel technical route provides a new idea for the design of metal matrix composites. [ABSTRACT FROM AUTHOR]

Removal of aluminum (abbreviated to Al) accounts for the main step for synthesizing Ti3C2Tx MXene. To date, the synthesis of Ti3C2Tx MXene is hampered by the low removal efficiency of Al from Ti3AlC2. Ultrasound was therefore introduced to achieve efficient synthesis of Ti3C2Tx MXene by promoting the removal rate of Al from Ti3AlC2. It was found that ultrasonic aid can significantly boost the removal efficiency of Al. Additionally, distinct kinetics for the removal of Al was recognized as the advent of ultrasonic intervention: (i) the shrinking core model was used to describe the removal kinetics of Al in the case without ultrasound, whilst the shrinking particle model was capable for the case in presence of ultrasound; (ii) the activation energy for removal of Al with ultrasonic aid was 70.2 kJ/mol, indicating a chemical reaction-controlled process, whereas the corresponding value for the case without sonication was 28.1 kJ/mol, demonstrating a mixed kinetic feature of the removal process of Al. Morphological study showed that ultrasound can remove the surface-adhering reaction products and favors the formation of structures with flower-like morphology. The sample without sonication treatment exhibited typical capacitive behavior, whilst the contribution of diffusion-limited capacitance in addition to the capacitive behavior was readily observed for the sonication-treated sample. Surface chemistry study indicated the more prevalent oxidation of the sonication treated sample, which gave rise to a higher specific capacitance than those without sonication treatment.

Al-Ti-C master alloy agent is currently the most promising grain refiner. This work investigates the influence of Ti3AlC2 addition (1.0–3.0 wt.%) on the microstructure of a hypoeutectic cast iron (4.7 wt.% Cr, 2.3 wt.% C). Microstructures of the samples were examined by SEM (scanning electron microscope). It was demonstrated that the added Ti3AlC2 did reduce the size of coarse primary carbides. The XRD (X-ray diffraction) pattern shows that Ti3AlC2 is decomposed into TiC in the alloy substrate. The EDS (energy dispersive spectrometer) interfacial element analysis shows that TiC combines well with the matrix interface. As the Ti3AlC2 amount was increased, the finest microstructure was achieved. When 2 wt.% Ti3AlC2 was added, the wear-resistance property of the material improved and became two times harder than the former. However, when 3% Ti3AlC2 was added, TiC gathered at the crystal boundary, which caused a decrease in the wear resistance of the material. [ABSTRACT FROM AUTHOR]

Ti3AlC2 ceramics were heat treated at the temperature from 1050 to 1450 °C. Vickers hardness, fracture toughness, flexural strength and compressive strength of Ti3AlC2 were tested and calculated before and after heat treatment, respectively. Ti3AlC2 content, fracture toughness, flexural strength and compressive strength of Ti3AlC2 first increase and then decrease, while Vickers hardness is just the opposite with the increase in temperature from 1050 to 1450 °C. After heat treatment at 1250 °C, Ti3AlC2 content reaches the highest level of 94.2 wt%, and fracture toughness, flexural strength and compressive strength reach the maximum values, which are 6.4 MPa·m1/2, 318 MPa and 662 MPa, respectively. Vickers hardness reduces to the lowest value of 2.9 GPa. Heat treatment does improve the strength and Ti3AlC2 content, but reduces the hardness and optimizes the mechanical properties of Ti3AlC2. [ABSTRACT FROM AUTHOR]

Modulating the thermal conductivity has been a pragmatic approach for the development of high-performance thermoelectric material and thereby a step forward towards commercialization. Despite some efforts, the reduction in thermal conductivity of SrTiO 3 ceramic has not been fully realized. In this work, Ti 3 AlC 2 in 3, and 7 vol% were uniformly incorporated in SrTiO 3 through nanostructured powder processing. The pristine SrTiO 3 and composites powders were consolidated by the spark plasma sintering at 1200 °C under uniaxial pressure of 50 MPa. Thermal properties of the bulk samples were evaluated from room temperature to 750 K through laser flash analysis. The thermal conductivity of SrTiO 3 based composites decreases substantially with the addition of nanostructured Ti 3 AlC 2 from the pristine SrTiO 3 bulk sample. The reduction in thermal conductivity of 7 vol% composites is more than 30% at room temperature and even higher at elevated temperatures from the SrTiO 3. The interface thermal resistance was estimated which indicates a dominant role in diminishing the thermal conductivities of the composites. The results suggest that the addition of Ti 3 AlC 2 as a second phase and nanostructuring through ball milling has significantly altered the phonon scattering mechanisms through multiple factors and thereby contributed to reducing effective thermal conductivities of the composites. This, work provide a scalable and economical route for the development of high-performance thermoelectric material. [ABSTRACT FROM AUTHOR]