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Titanium alloys are applied in oil and gas development and transportation to improve conditions because of their high specific strength and corrosion resistance. However, the disadvantage of poor wear resistance has become an obstacle to developing titanium alloys. The friction and wear properties of pure titanium TA3 and titanium alloy TA10 were tested under different loads and different friction forms using a reciprocating friction and wear tester. Moreover, the erosion resistance of pure titanium TA3 and titanium alloy TA10 was studied using a gas–solid erosion tester. The results show that the wear rate of TA3 and titanium alloy TA10 increases with increasing friction load. Under a load of 50 N, the mass losses of TA3 under dry friction and wet friction were 0.0013 g and 0.0045 g, respectively, while the mass losses of TA10 were 0.0033 g and 0.0046 g, respectively. While the load increased to 70 N, the mass loss of TA3 was even greater, reaching 0.0065 g, and the mass loss of TA10 was 0.0058 g. The wear forms of TA3 and TA10 include abrasive wear, adhesive wear and oxidation wear. The joint action of various friction forms leads to the loss of materials. Under the simulated working conditions, the erosion rates of TA3 and TA10 were 1.01 × 10−3 g/s and 0.94 × 10−3 g/s. The erosion mechanism is the same, including plowing, indentation and cracking. [ABSTRACT FROM AUTHOR]

The paper presents a comparative study of the erosion wear resistance of WC-10Co4Cr, Cr3C2-25NiCr and martensitic stainless steel (SS) coatings deposited onto an AlSi7Mg0.3 (Al) alloy substrate by high-velocity air‒fuel (HVAF) spraying. The influence of the abrasive type (quartz sand or granite gravel), erodent attack angle, thickness, and microhardness of the coatings on their and Al substrate's wear resistance was comprehensively investigated under dry erosion conditions typical for fan blades. The HVAF-spraying process did not affect the Al substrate's structure, except for when the near-surface layer was 20‒40 μm thick. This was attributed to the formation of a modified Al-Si eutectic with enhanced microhardness and strength in the near-substrate area. Mechanical characterization revealed significantly higher microhardness values for the cermet WC-10Co4Cr (~12 GPa) and Cr3C2-25NiCr (~9 GPa) coatings, while for the SS coating, the value was ~5.7 GPa. Erosion wear tests established that while Cr3C2-25NiCr and SS coatings were more sensitive to abrasive type, the WC-10Co4Cr coating exhibited significantly higher wear resistance, outperforming the alternatives by 2‒17 times under high abrasive intensity. These findings highlight the potential of HVAF-sprayed WC-10Co4Cr coatings for extending the service life of AlSi7Mg0.3-based fan blades exposed to erosion wear at normal temperatures. [ABSTRACT FROM AUTHOR]

This paper aims on evaluating the erosion wear behavior of epoxy composites reinforced with ramie fibers. The possibility of reinforcing ramie fiber to improvise the wear resistance of epoxy is investigated in this study. Composites are fabricated by reinforcing multiple layers of woven ramie fiber mats into epoxy resin using conventional wet lay‐up technique and erosion wear trials are conducted using solid particle erosion test setup. Taguchi analysis is done to assess the relative significance of each of the factors influencing the erosion rate using L16 orthogonal array. The analysis reveals that the impact velocity followed by impingement angle are the most significant control factors affecting the erosion wear rate of ramie‐epoxy composites. Steady state erosion analysis is done to ascertain the effect of each of the significant factors while keeping other factors fixed. Further, an analytical and predictive model based on the principle of neural computation is used to predict the rate of erosion wear of the composites and the obtained results are compared with the experimental outcomes. The worn morphologies of the eroded surfaces of the composites are studied and analyzed to identify possible mechanisms causing wear. [ABSTRACT FROM AUTHOR]

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To evaluate the enhanced erosion wear performance under acidic medium, a new high-vanadium–chromium alloy (HVCA) is designed and test samples produced by sand casting. The microstructure was analyzed by SEM, TEM and XRD. The erosion wear performance was tested in acidic medium designed by orthogonal test method. The factors affecting the erosion wear performance of HVCA are analyzed. The research results show that microstructure of HVCA is characterized by different carbides (M7C3, M23C6, VC, M2C) distributed in martensite and residual austenite. The hardness is 65.16 ± 0.2 HRC, and the impact toughness is 9.82 ± 0.12 J/cm2. H2SO4 concentration has the greatest influence on the erosion wear performance of HVCA, followed by the erosion wear angle. The maximum erosion wear performance of HVCA is 1.59 times that of HCCI. Compared with HCCI, HVCA has excellent erosion wear resistance because of its high hardness and toughness, a small amount of fracture and carbide shedding, and slight corrosion and wear interaction under erosion wear condition. [ABSTRACT FROM AUTHOR]

Wear and erosion wear represent primary failure mechanisms in flow passage components, and proactive preventive maintenance can effectively extend their service life. This study investigates the utilization of laser metal deposition technology for the additive manufacturing of 17-4PH stainless steel (17-4PHss) followed by solid solution aging treatment. Structural transformations before and after the solution aging treatment, along with the dry wear and erosion wear properties of 17-4PHss post-heat treatment, were examined. During the heat treatment process, the solid solution treatment fully transformed the microstructure to martensite, alleviating the stress generated by the additive process, and refined the microstructure to 0.64 μm. The subsequent aging treatment further refined the grains, ultimately reducing the grain size from 0.68 μm in the additive state to 0.62 μm. Compared to traditional casting, the grain size of 17-4PHss was reduced by 6.83%. Additionally, NbC was uniformly distributed in the sample, playing a secondary phase strengthening role, resulting in high microhardness (455.5 HV0.2). Simultaneously, the solid solution-aged (SSA) sample exhibited robust wear resistance, manifesting abrasive wear at low loads. With increasing load, a transition to abrasive wear and adhesive wear occurs, accompanied by oxidative wear and fatigue wear. At a 30 N load, the specific wear rate of the SSA sample decreased to 0.17 × 10−5 mm3/Nm, attributed to the more stable microstructure of the SSA sample under high loads. In the erosion wear test, the cumulative mass loss of the sample after heat treatment was the lowest (10.71 mg/m2h), with the erosion wear mechanism attributed to plastic deformation and micro-cutting. [ABSTRACT FROM AUTHOR]

• Particle size is the dominant factor influencing the trend of load variation. • The variation in speed can influence the phenomena of atomic stacking faults and rearrangement. • The variation in speed can lead to wear of different orders of magnitude in impact simulations. The application of titanium carbide (TiC) coatings, renowned for their exceptional tribological properties, holds promise for the research on failure prevention in downhole petroleum machinery. In this study, molecular dynamics was employed to coat TiC layers onto Fe surfaces to enhance wear resistance. The effects of particle size and velocity on the wear and erosion resistance failure of the entire system were investigated through nanoindentation, scratch tests, and particle impact studies. The results indicate that the influence of particle size on the abrasion resistance and erosion resistance of materials is manifested in the load trend and surface atomic morphology. In the plastic damage of materials, an increase in velocity weakens the accumulation of slip faults and rearrangement phenomena among internal atoms, resulting in irregular fluctuations in the load curve. Meanwhile, the high-speed system will dominate the influence on temperature by accelerating atomic motion, leading to different orders of magnitude of wear and high-temperature atoms in impact simulations compared to particle size. This provides significant reference for the study of protective failure of TiC coatings in complex oil machinery service environments. [ABSTRACT FROM AUTHOR]

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present research work represents comparative results on the erosion wear and erosion wear resistance of coatings, deposited by supersonic flame jet (HVOF), which contain composites having Ni-Cr-B-Si of different chromium concentrations - 9.9%; 13.2%; 14%; 16% and 20%, at identical particle size 45 µm and identical contents of the elements boron and silicon. The coating, prepared having 20% Cr does not contain the elements B and Si. Coatings have been obtained from each powder composite without any preliminary thermal treatment of the substrate and with some preliminary thermal treatment of the substrate up to 650°C. The coatings have been tested under identical conditions of erosion in air stream, carrying abrasive particles. Results have been obtained on the dependence of the mass wear, the intensity of erosion and the erosive wear resistance as a function of the Cr concentration in the coatings with and without thermal treatment of the substrate at two angles of the stream 60° and 90°. It has been ascertained that in all the cases of coatings the preliminary thermal treatment of the substrate leads to a decrease in the intensity of wear, i.e. enhancement of the erosive wear resistance. It has been shown that the angle of the jet stream influences the wear resistance of all the coatings: at jet angle 60° the wear resistance grows up within the interval from 1.5 up to 2.6 times for the coatings without thermal treatment of the substrate and within the interval from 1.6 up to 3.5 times for the coatings under going thermal treatment of the substrate in comparison with the wear resistance at angle 90°. This effect is strongest - 3.5 times for the coating No 8 of 16% Cr. At jet angle 90° the wear resistance increases up to 10% and this increase is one and the same for all the coatings. The obtained dependence of the erosive wear resistance on the Cr concentration has strongly expressed non-linear character. Upon increasing the Cr concentration the wear resistance grows up and it reaches a maximum for coatings of 16% Cr with thermal treatment of the substrate at jet angle 60°. It has been found out that the wear resistance of the coatings, having the highest Cr content - 20%, but not containing the elements boron and silicon, is lower or almost equal to the wear resistance of the coatings having the lowest Cr concentration - 9.9%. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to carry out erosion wear investigation on high-velocity oxy-fuel (HVOF)-deposited 86WC-10Co4Cr and synergistic Ni/Chromia powder (i.e. 80Ni-20Cr2O3) on AISI 316L. Design/methodology/approach: Design of experiments-artificial neural network (DOE-ANN) methodology was adopted to calculate the erosion wear. Taguchi's orthogonal array L16 (42) was used to perform set-of-erosion experiments followed by lower-the-better rule. The artificial neural network (ANN) model is used on erosion wear data obtained from the experiments. Findings: Experimental results indicate that 86WC-10Co4Cr provided better erosion wear resistance as compared to Ni/Chromia. The erosion wear of 86WC-10Co4Cr and synergistic Ni/Chromia coatings increases with an increase in time duration, solid concentration and time. The magnitude of erosion generated by ashes was comparatively lower than sand. The arithmetic mean roughness (Ra) of finished AISI 316L, 86WC-10Co4Cr and Ni/Chromia coating was found as 0.46 ± 0.13, 6.50 ± 0.16 and 7.04 ± 0.23 µm, respectively. Surface microhardness of AISI 316L, 86WC-10Co4Cr and Ni/Chromia coating was found as 197 ± 18, 1,156 ± 18 and 1,021± 21 HV, respectively. Practical implications: The present results can be useful for estimation of erosion wear in slurry pumps used in mining industry for the conveying of sand and in thermal power plants for the conveying of ashes to the dyke area. Originality/value: The erosion wear of HVOF-sprayed 86WC-10Co4Cr and Synergistic Ni/Chromia powders was studied experimentally as well as predicted by the ANN model, and wear mechanisms are well discussed by scanning electron micrographs. [ABSTRACT FROM AUTHOR]

Erosion wear of the centrifugal pump impeller are the key issues since its operating in sediment-laden flow. Experiment and numerical method are adopted in this study to investigate the erosion wear of the impeller in a double-suction pump in the Jingtai Yellow River Irrigation Project (JYRIP). Observation during operation combined with morphology study is carried out to verify erosion mechanisms at the different sections of the impeller blade. For numerical study, the Eulerian-Lagrangian approach combined with the Mclaury model is employed to predict the trajectories of the particles under different particle parameters. Also the effects of particle size and concentration on impeller erosion wear is studied. Numerical results are consistent with experimental data. The surface wear of the blade changes obviously from circular shape to strip shape in the direction from the Leading Edge (LE) to the Trailing Edge (TE), and the wear damage area increases correspondingly. Trajectories of larger particles are more uniform and tend to cause more severe erosion wear damage. The wear damage tends to be slow after the particle size increases to a certain extent under the same sediment concentration. Besides, erosion rate increases with an increase in sediment concentration, and the erosion rate of the suction side is greater than the pressure side at the same position of the blade surface. These results can offer a good reference for the design of wear resistance impeller o f the double suction pump. [ABSTRACT FROM AUTHOR]

Erosion wear of the centrifugal pump impeller are the key issues since its operating in sediment-laden flow. Experiment and numerical method are adopted in this study to investigate the erosion wear of the impeller in a double-suction pump in the Jingtai Yellow River Irrigation Project (JYRIP). Observation during operation combined with morphology study is carried out to verify erosion mechanisms at the different sections of the impeller blade. For numerical study, the Eulerian-Lagrangian approach combined with the Mclaury model is employed to predict the trajectories of the particles under different particle parameters. Also the effects of particle size and concentration on impeller erosion wear is studied. Numerical results are consistent with experimental data. The surface wear of the blade changes obviously from circular shape to strip shape in the direction from the Leading Edge (LE) to the Trailing Edge (TE), and the wear damage area increases correspondingly. Trajectories of larger particles are more uniform and tend to cause more severe erosion wear damage. The wear damage tends to be slow after the particle size increases to a certain extent under the same sediment concentration. Besides, erosion rate increases with an increase in sediment concentration, and the erosion rate of the suction side is greater than the pressure side at the same position of the blade surface. These results can offer a good reference for the design of wear resistance impeller of the double suction pump. [ABSTRACT FROM AUTHOR]

SS 410 is widely used as pump impeller material due to its high erosion resistance property. On the other hand, the microhardness of SS 410 is comparatively lower than other steels. So in this paper, WC-10Co-4Cr and WC-10Co-4Cr + 2%Y2O3 (yttrium oxide) powders are used to improve the microhardness of SS 410. The erosion due to fly ash slurry mixture has been inspected in a slurry pot analyzer. The erosion wear experiments were performed for equisized slurry of different particle size range, namely <53 µm, 53–106 µm, 106–150 µm, and 150–250 µm. During the experimentation, concentration of fly ash slurry was varied from 35 to 65%. The rotation speed of pot tester was taken as 750, 1000, 1250 and 1500 rpm. Experiments were repeated for different time durations like 75, 120, 165 and 210 min. A high velocity oxygen fuel coating technique was utilized to deposit the coating powders on the pump impeller materials SS 410. WC-10Co-4Cr sprayed SS 410 was found to have better erosion wear resistance as compared to bare SS 410. The addition of 2% Y2O3 in WC-10Co-4Cr has enhanced the erosion wear resistance based on change in hardness from 1130 HV to 1190 HV and because of the densification impact of Y2O3. [ABSTRACT FROM AUTHOR]

The dynamic impact test is a tool for investigating the impact wear of the coated samples. In the dynamic impact test, the indenter successively impacts the same place of the sample surface with a constant, well-defined impact load and frequency. This paper focuses on the study of the impact wear of superalloy Co-based HVOF-sprayed coatings, CoCrW and CoCrAlYTaCSi. The impact wear of the coatings was discussed with respect to their mechanical properties and microstructure. The results of the impact wear of the coatings were compared with the results of the erosion wear tests and the sliding/abrasion wear tests. The correlation of impact wear resistance with the resistance of solid particle erosion was confirmed, on contrary to abrasive and sliding wear. • Co-based HVOF-sprayed coatings are often exposed to the repetitive impact load. • Impact behaviour of the wear-resistant CoCrW and CoCrAlYTaCSi coatings was studied. • Impact lifetime depended on the ability of the plastic deformation related to H3/E2. • Evolution of the subsurface cracks was studied in detail by SEM. • Impact test results were compared with the solid particle erosion wear test results. [ABSTRACT FROM AUTHOR]

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Now-a-days, natural fibers have been receiving considerable attention as the substitute for synthetic fiber reinforcement in plastics. Among various fibers, coir is the most widely used natural fiber due to its advantages like easy availability, low cost, low density, low production cost and satisfactory mechanical properties. Fiber-reinforced polymer composites often have to function in severe erosive environment in which they encounter solid particle erosion. To this end, an attempt has been made in this paper not only to study the utilization potential of coir fiber in polymer composites, but also to study the effect of various parameters on erosion wear performance of coir fiber-reinforced epoxy composites filled with Al2O3 filler. Twenty different composite samples were prepared with different length (3 mm, 6 mm, 9 mm, 12 mm, and 15 mm) and content (5 wt%, 10 wt%, 15 wt% and 20 wt%) of fiber using hand lay-up technique. The erosion wear of these composites has been evaluated at different impingement angles (30°, 45°, 60°, 75°, and 90°) and at different impact velocities (48 m/s, 70 m/s, 82 m/s, and 109 m/s). The effect of fiber length and content on the erosion wear behavior of composites is also analyzed. A comparison has been made between composites with and without Al2O3 filler. It has been observed that composites filled with Al2O3 filler show better wear resistance properties as compared to composites without filler. To characterize the morphology of eroded surfaces and the mode of material removal, the eroded specimens are observed under scanning electron microscope. [ABSTRACT FROM AUTHOR]

Damage of structural components of hypersonic vehicles by atmospheric particles demands thorough understanding on their wear behavior. In the present work, dense ZrB 2 -SiC (10, 20, and 30 vol%) composites are prepared by spark plasma sintering at 55 MPa in two stages: 1400 °C for 6 min followed by 1600 °C for 2 min. With increase in SiC content, microstructures of sintered composites reveal strongly bonded ZrB 2 grains with SiC particles. A combination of maximum hardness of 23 GPa, elastic modulus of 398 GPa and fracture toughness of 5.4 MPa m 1/2 are obtained for the composite containing 30 vol% SiC particles. It is found that cracks are bridged or deflected by SiC particles in the composites. When the composites are subjected to SiC particle erosion at 800 °C, a 14% decrease in erosion rate is obtained with increase in SiC content from 10 to 30 vol%. The formation of large extent of boro-silicate rich viscous surface on eroded surfaces is attributed to reduced fracture or removal of ZrB 2 grains of the composites with increased SiC content. [ABSTRACT FROM AUTHOR]

Centrifugal slurry pump is widely used for transportation of solids through pipeline in many chemical and mining industries. Erosion wear considered as one of the important parameter which plays significant role in slurry transportation system by affecting both initial cost and life of its components. In the present work, erosion wear due to solid–liquid mixture has been investigated using a slurry erosion pot tester. The erosion tests have been conducted on centrifugal slurry pump material stainless steel (SS304) to establish the influence of rotational speed, particle size, solid concentration and time duration. Sand and fly ash were taken as erodent materials with solid concentrations ranging from 30 to 60% (by weight). The experiments were performed at four different speeds namely 600, 900, 1200 and 1500 rpm with time duration of 90, 120, 150 and 180 minutes. WC–10Co–4Cr and Ni–20Cr 2 O 3 coating powders were used to increase the erosion wear resistance. Coating powders are deposited on pumping material by supersonic flame of high velocity oxygen fuel (HVOF) coating. Experimental results indicate that erosion wear has high dependence on rotational speed, time duration and nature of erodent solid particles. Significant improvement in erosion wear resistance was also observed by using WC–10Co–4Cr coating over Ni-20Cr 2 O 3 . [ABSTRACT FROM AUTHOR]

The pipeline is an essential device in chemical engineering and energy industries, which is referred to as the "industrial arteries". Under severe working conditions, fluid-solid erosion wear easily occurs on the pipeline wall and causes major safe and pollution accidents. However, a comprehensive review of coping strategies for pipelines' fluid-solid erosion wear is not yet available. This paper summarizes four coping strategies for the fluid-solid erosion wear of pipelines: erosion wear modeling, erosion wear detecting, resistance to erosion wear, and erosion wear risk assessment (health management). This review analyzes and reviews the current status of research on pipeline erosion from both theoretical and applied perspectives. Moreover, the development trend of coping strategies for pipelines' erosion wear is foreseen. It is expected that some inspirations and valuable references will be drawn from this paper to guarantee the safe operation of the pipeline system for a long time. [Display omitted] [ABSTRACT FROM AUTHOR]

The electrochemical corrosion and erosion wear behaviors of detonation sprayed ODS FeAl powder coatings on T91 substrate were investigated. Electrochemical corrosion resistance of the deposited coatings was evaluated in three different aqueous media, namely 3.5 wt% (0.61 M) NaCl, 2 N (1 M) H 2 SO 4 and 3.5 wt% (0.25 M) Na 2 SO 4 and are compared with T91 substrate and detonation sprayed Cr 3 C 2 –25NiCr coatings (on T91 substrate). The ODS FeAl coatings shown improved corrosion resistance in 3.5 wt% Na 2 SO 4 than T91 substrate. However, the Cr 3 C 2 –25NiCr coatings have shown consistently better corrosion resistance than T91 substrate and ODS FeAl coatings in all the aqueous media. The corrosion mechanisms investigated imply that the higher corrosion rate of FeAl coatings as compared to the Cr 3 C 2 –25NiCr coatings is well compensated by the uniform corrosion in the case of former than the localized and intense corrosion in the case of later coatings and substrate material. In contrast, the solid particle erosion wear studies conducted at two different temperatures namely, room temperature (25 °C) and 400 °C have revealed that the ODS FeAl coatings exhibited 4 to 5 times improved wear resistance than that of Cr 3 C 2 –25NiCr coatings at room temperature and 1.5 to 2.5 times at a higher temperature (400 °C). Also, the ODS FeAl coatings have performed marginally better than the T91 substrate at both the test temperatures. The results obtained together with the observations made demonstrate a leap step towards the development of novel thermal spray grade feedstock materials as an alternative to industrially well-known Cr 3 C 2 –25NiCr coatings and open up a new avenue of techno-economic benefits that can be further explored. [Display omitted] • ODS FeAl coatings were developed with in-house synthesized powder using detonation spray. • ODS FeAl coatings exhibited hardness values of HV 0.3 450, two times higher than steel. • Uniform corrosion was noticed in ODS FeAl coatings as against a localized attack in Cr 3 C 2 –25NiCr coatings. • Superior erosion resistance of ODS FeAl coatings indicate their potential applications. [ABSTRACT FROM AUTHOR]

The aim of this study is to determine the damage mechanisms affecting 304L Stainless Steel (SS) parts used in olive oil production, and to evaluate the performance of TiN coatings in improving their resistance to these effects. Tribological behavior of 304L SS parts was investigated through pin on disc tests against olive seed counter bodies, both in uncoated state and after TiN coating via cathodic arc physical vapor deposition. Further assessment of tribological behavior was carried out through the means of an in house centrifugal testing setup, designed to simulate the environment encountered during the de­seeding step of oil production, and cavitation erosion tests with an ultrasonic probe. The results of pin on disc tests showed considerable wear damage of uncoated SS while TiN coated samples exhibit excellent wear resistance, with no visible damage to the coatings. Further results obtained from centrifugal tests indicated a damage mechanism related to impact from olive seed particles. Plastic deformation of the SS substrate surface was observed via SEM, both for uncoated and TiN coated samples, leading to fracturing of the TiN coatings and their subsequent removal in the latter. This observation is supported by the results of cavitation erosion tests, in which similar damage can be observed on TiN coated SS samples. The same test carried out on TiN coated high speed steel samples which have a higher substrate hardness than SS showed better resistance to fracture of the coating. [ABSTRACT FROM AUTHOR]

Tempering is a necessary heat treatment process to ensure that the surface of the carburized material has adequate strength and the core has sufficient toughness. In this work, the carburized layer was tempered several times at medium temperature (400–440 °C) and the effect of tempering temperature, and number of times on microstructure, plastic toughness, and wear properties in complex environments was investigated in detail. The modified layers of the tempered samples were characterized by martensite, carbide, and a small amount of residual austenite. Primarily, the results show that the maximum ultimate tensile strength (UST, 1441 MPa) and elongation (11.4 %) were obtained with 3 times tempering at 400 °C. Simultaneously, the least erosion wear rate (0.61 mg/g) was obtained for 400 °C 3-times tempered specimens. Then, under dry friction conditions, the friction coefficients of the 3-times tempered were inferior to those of the 5-times tempered samples. In the subsurface layer, the 420 °C 3-times tempered samples had the minimum wear rate (1.73 × 10−15 m3N−1 m−1). Nevertheless, the friction coefficient under oil lubrication is dramatically lower compared to the dry friction coefficient. Finally, the medium temperature multiple tempering ensured a well-balance of wear resistance and plastic toughness. [Display omitted] • Heat treatment technology for both strength and toughness upgrade is proposed. • Multiple tempering at mid-temperature has a positive role on the mechanical properties of carburized layer. • After tempering, the ultimate tensile strength was up to ~1441 MPa and the elongation was 11.4 %. • The erosion wear rates are minimized for 400 °C-3 times tempering. [ABSTRACT FROM AUTHOR]

The resistance of high velocity oxy-fuel (HVOF) sprayed TiC-NiMo and Cr3C2-Ni cermet particles reinforced NiCrSiB self-fluxing alloy coatings to high temperature erosion wear was studied. Microstructure of the coatings was examined by SEM, phase composition was determined by XRD. A four-channel centrifugal particle accelerator was applied to study the high temperature erosion wear of the coatings. The angles of impingement were 30° and 90°, initial particle velocity was 50 m/s, the average temperature of the test - 650 °C. Volume wear of the coatings was calculated and compared to the respective values of the reference materials. Wear mechanisms were studied by SEM. HVOF sprayed coatings exhibited lower wear, than WC-15Co hardmetal and steel HARDOX 400, but higher wear than steel AISI 304. TiC-NiMo particles reinforced self-fluxing alloy coating demonstrated virtually the same wear resistance, as the Cr3C2-Ni particles reinforced self-fluxing alloy coating, at 30° and the better wear resistance at 90°. [ABSTRACT FROM AUTHOR]

The present work investigates comprehensively the tribological behaviour of WC-Cr 3 C 2 -Ni coatings prepared by atmospheric plasma spray (APS) and high-velocity oxy-fuel (HVOF) spray methods. The dry sliding wear at room and elevated temperature (up to 800 °C), wet (oil-based fracturing fluid) sliding wear at room temperature were studied against an alumina ball using the ball-on-disc tribometer according to the ASTM G99 standard. The erosion wear was studied using air-jet erosion tester (ASTM G76) at the impact angles 30° and 90° and temperatures 500 °C and 650 °C. The HVOF coating showed higher hardness, dense morphological structure and a lower degree of decarburisation as compared to APS coating. The HVOF coating offers better wear resistance over the APS coating under both dry and wet sliding conditions. Significant improvement in the wear resistance, especially above 500 °C is attributed to the uniform formation of lubricious WO 3. The solid particle erosion resistance of both coatings is observed to be the same up to 650 °C under 30° and 90° impact angles. • HVOF coating has better wear resistance under dry and wet sliding conditions. • Lubricious tribo-film controls the wear under high-temperature in both coatings. • Higher erosion resistance of HVOF coating than APS coating • Higher wear in APS coating due to more decarburization, lower hardness and interlamellar cohesion [ABSTRACT FROM AUTHOR]

This study attempted to investigate the effect of coating porosity on the ability to protect the substrate from corrosion and the combined action mechanism of corrosion and erosion wear. In this study, five coatings with different porosity characteristics were deposited on the substrate. The microstructures and phase composition of coatings were characterized. Furthermore, corrosion and erosion wear behavior of coatings were analyzed. The erosion wear patterns of uncorroded and corroded coatings were revealed. The mechanism that erosion wear was influenced through corrosion was determined. Results indicated that corrosion and erosion wear resistance were remarkably affected by porosity. The unsealed cermet failed to protect the substrate and aggravated the corrosion of the substrate through galvanic corrosion. Porosity affected the microcutting performance by influencing hardness, whereas corrosion affected the microcutting and deformation wear performance by acting on hardness, resulting in the loosened structure. The main erosion mechanisms of uncorroded and corroded coatings were microcutting and deformation wear, respectively. Deformation wear was induced by corrosion, and microcutting. The qualitative analysis of the combined action of corrosion and erosion can provide guidance in coating design. • Unsealed coating promoted substrate galvanic corrosion, not surface corrosion. • Revealed negative effects of porosity on erosion and corrosion resistance • Revealed erosion wear patterns of corroded and uncorroded coatings • Revealed the mechanism that erosion wear affected by corrosion [ABSTRACT FROM AUTHOR]

High temperature erosion tests were conducted on spark plasma sintered ZrB 2 -SiC based multiphase ceramic composites at 1073 K in thermo-erosive environment for 1200 s with a net energy deposition per unit area of 50.5 MJ/m2. The thermo-erosive mechanisms were qualitatively discussed using XRD and SEM-EDS analyses. Efforts were made to assess feasibility of identified reactions at the computed temperatures to support reaction mechanism for oxide formation in eroded region. Finite element (FE) analysis with high-quality structural elements was used to determine the spatial temperature and stress distribution in the eroded region. Taken together, the present study highlights the significance of combined approach of computational and experimental analysis in understanding the thermo-erosive-structural stability in applications where erosion can limit the performance of ceramic composites. • For the first time, the present work demonstrates the significance of computational analysis in understanding the wear behavior of ZrB 2 -18SiC and ZrB 2 -18SiC-10Ti composites in high temperature erosion conditions. • The reduced effect of mechanical properties improvement on high temperature erosion wear resistance could be explained by stress distribution in eroded regions. • As per the computational analysis, almost one order of magnitude higher stresses is found in eroded region of ZrB 2 -18SiC-10Ti composite compared to ZrB 2 -18SiC composite. [ABSTRACT FROM AUTHOR]