The development of novel thermal barrier coating (TBC) materials is crucial for enhancing the durability of aeroengines under extreme operating conditions. Rare-earth tantalates have emerged as promising TBC candidates owing to their high phase stability and chemical inertness. In this study, La3TaO7 powders with high crystallinity and thermal stability were synthesized via solid-state reaction, and bulk samples with different porosities were subjected to CMAS corrosion tests. The results reveal a clear correlation between porosity and CMAS attack: low-porosity La3TaO7 forms a dense reaction layer dominated by CaTa2O6 and Ca2La8(SiO4)6O2, effectively blocking CMAS infiltration, while high porosity promotes capillary-driven infiltration of molten CMAS through interconnected pores, leading to accelerated corrosion. Compared with conventional YSZ and rare-earth zirconates, La3TaO7 exhibits significantly lower corrosion rates (1.75 mu m/h), demonstrating superior CMAS resistance. Furthermore, gradient-porosity La3TaO7 coatings were fabricated, which not only relieve thermal expansion mismatch stresses during thermal cycling but also retard oxygen ingress, thereby imparting enhanced thermal shock resistance. These findings provide fundamental insights into the CMAS corrosion mechanisms of La3TaO7 and highlight its potential as a next-generation TBC material with excellent environmental durability.

To address the critical failure challenges of plasma-sprayed metal-ceramic composite coatings under harsh high-temperature chloride-containing aqueous solutions industrial environments, including severe interfacial galvanic corrosion, preferential penetration of Cl-, and rapid degradation of passive films, an innovative grain/ phase boundary-directed Cr enrichment strategy was proposed. NiCrBSi-TiCrN composite coatings with gradient Cr contents were fabricated via reactive plasma spraying. Through electrochemical testing equipment (EIS, SECM) combined with microstructural characterization (XRD, SEM, TEM, XPS, Raman spectroscopy), the dynamic corrosion mechanisms and product layer evolution of the coatings under multi-time-period exposure to an 80 degrees C, 3 % Cl-environment were systematically investigated. Our study reveals a "dual regulatory effect" in the Cr-rich regions at crystal/phase boundaries: these regions function both as local auxiliary anode that preferentially dissolve to provide a continuous Cr3+ source, and as suppressors of galvanic corrosion by reducing the potential difference between the metallic and ceramic phases, thereby overcoming the limitations of traditional single-passivation protection. It clarifies the evolution mechanism of the corrosion product layer, establishes a composite protective structure consisting of a "dense inner layer of Cr2O3 and FeCr2O4" and an "outer layer of Fe-based oxides," and clarifies the dynamic formation pathway of this composite structure. Through thermodynamic quantification, the preferential deposition sequence of Cr2O3 (peak supersaturation 3.83 & times; 105) and FeCr2O4 was determined, revealing that product deposition is governed by "ion diffusion-supersaturation matching." Results indicate that the icorr of the Ni-Cr35 coating decreased by one order of magnitude compared to Ni-Cr15, with Eop significantly shifting to-0.5403 V. This work provides a feasible interfacial engineering route for designing durable protective coatings applied in high-temperature Cl-environment petrochemical and marine engineering systems.

Reaction plasma spraying technology was employed to fabricate NiCrBSi-TiCrN composite coatings enriched with Cr at the grain/phase boundaries. The influence of Cr content on the coating microstructure, electrochemical characteristics at phase interfaces, and corrosion resistance in Cl-environments was systematically investigated, revealing the corrosion resistance mechanism of the coatings. XRD, SEM, and AFM were used to characterize the phase composition, microstructure, and surface potential distribution. The electrochemical corrosion resistance of the coating was evaluated through dynamic polarization, EIS, and SECM analyses. Raman spectroscopy and XPS were employed to investigate the phase composition of corrosion products. Results indicate that when the Cr content in Ti-Cr composite powder exceeds 25 wt%, Cr-enriched regions form at the TiCrN/ gamma-Ni phase interface, thereby enhancing interfacial compactness and regulating interphase electrochemical potentials. AFM measurements reveal that the interphase potential difference decreases from 0.0412 V (Ni-Cr15) to 0.0238 V (Ni-Cr35). With increasing Cr content, the self-corrosion potential of the coating shifted positively from-0.971 V to-0.782 V. At the same time, the corrosion current density decreased from 5.964 & times; 10-5 A/cm2 to 4.403 & times; 10-5 A/cm2. Low-Cr coatings suffer severe interphase galvanic corrosion and form loose Fe-based products, accelerating failure. High-Cr coatings achieve dual functions through Cr-enriched phase boundaries: forming a dense structural barrier and regulating potential differences. Sacrificial Cr oxidation shifts the corrosion pathway from interphase corrosion dominance to "intergranular limited corrosion + dense film protection at grain/phase boundaries," effectively suppressing Cl-erosion. Therefore, potential difference regulation and interphase corrosion inhibition dominated by Cr-rich phase boundaries constitute the core mechanism enabling the NiCrBSi-TiCrN composite coating's superior corrosion resistance in Cl-environments.

NbMoTaWCr RHEA powder and coating were prepared by mechanical alloying combined with laser cladding, and their phase, microstructure, friction and wear properties, and corrosion behavior under high-temperature molten salt were analyzed. The results show that the coating exhibits a typical dendritic structure composed of the main BCC phase and fine Cr2Nb-type Laves phase at the grain boundaries, with an elastic modulus of 112.64 +/- 5.21 GPa and a Vickers hardness of 943.1 +/- 10.2 HV0.2. Under dry friction conditions, its friction coefficient is 0.478, and the wear rate is 2.57 x 10-5 mm3/(N center dot m), representing a 70.2 % reduction compared to the matrix. In the molten salt corrosion environment of 75 % Na2SO4 + 25 % NaCl at 850 degrees C, the Cr2Nb-type Laves phase enriched with Cr elements at the grain boundaries helps prevent the formation of loose, unprotective corrosion products and blocks the penetration of corrosion media along the grain boundaries, thus enhancing the high-temperature molten salt corrosion resistance of the coating. The corrosion behavior involves a complex synergistic process of selective oxidation, sulfidation, and chlorination. The dense cladding layer transformed into a loose, porous structure.

This study explores the trade-off between densification and conductivity in pressureless-sintered antimony-doped tin oxide (ATO) ceramics by adding ZnO and CuO as dual sintering aids. The microstructure and electrical properties of ATO ceramics doped with different sintering aids were systematically examined through three experimental groups: ATO matrix, ZnO doping, and CuO doping as control groups. The results show that the combined effect of CuO and ZnO increases carrier concentration while promoting tissue densification. The relative density of the ATO sample doped with CuO and ZnO reached 95 %, with a grain size of 50 mu m. The carrier mobility was as high as 82.5 cm2/(V center dot s), and the resistivity was 8.38 & times; 10-degrees 52 center dot cm. Additionally, the resistivity change rate between room temperature and 450 degrees C was less than 7 %. This research offers valuable insights for the large-scale production of high-density, highly conductive ATO ceramics.

In this study, NiCrBSi-TiCrN composite coatings with varying Cr contents were prepared by plasma spraying technology and assessed for sliding wear behavior at 200 degrees C. The effects of optimizing the Cr content on the coating microstructure, high-temperature wear performance, and mechanical mixed layer formation mechanism were systematically investigated. XRD, SEM, and TEM techniques were utilized to characterize the phase composition and microstructure of the composite coatings before and after wear. A reciprocating friction and wear tester was employed to assess the wear behavior of the coatings. Also, Raman and XPS techniques were employed to analyze the sliding wear products of the coatings. The findings showed that the composite coating comprises gamma-Ni, Cr3C2, Cr3B4, TiCrN, and Ti3O phases, which become enriched in TiCrN grain boundaries when Cr exceeds the solid solution limit. Wear tests demonstrated that the Cr25 coating exhibits outstanding high-temperature wear resistance, with a wear rate (4.5268 x 10-8 mm3/Nm) reduced by 22 % and 18 % compared to Cr15 (4.8361 x 10-8 mm3/Nm) and Cr35 (5.5369 x 10-8 mm3/Nm), respectively. Simultaneously, its mating ball wear rate (1.1806 x 10-9 mm3/Nm) is reduced by 44 % and 30 % compared to Cr15 (2.0960 x 10-9 mm3/Nm) and Cr35 (1.6757 x 10-9 mm3/Nm), respectively. The coatings' wear behavior is influenced that brittle fracture-dominated three-body wear, accelerated wear chip refinement due to thermal-force coupling, and the establishment of anti-wear mechanisms through mechanically mixed layers. Optimizing the Cr content inhibits brittle fracture of TiCrN and prevents excessive softening that could lower hardness. This optimization promotes a stable mechanically mixed layer, which greatly enhances wear resistance. This research provides theoretical support and an experimental foundation for developing high-performance wear-resistant coatings suitable for wear conditions in oil extraction, which hold significant value in engineering applications.

High-entropy carbide ceramics are promising ultra-high-temperature materials for thermal protection in hypersonic environments. From the perspective of composition, this review analyzes the relationships and mechanisms between element selection, microstructure evolution, and properties. The current research on the phase formation rules of high-entropy carbides is reviewed from three perspectives: thermodynamic parameters, lattice distortion, and first-principles methods. Synthesis strategies for powders, bulk ceramics, and coatings are summarized, emphasizing challenges associated with sluggish diffusion, densification, and non-equilibrium processing. Particular attention is given to how metallic constituents govern microstructural evolution, thereby influencing mechanical performance, thermal transport, wear resistance, and oxidation/ablation behavior. Key mechanisms—including lattice distortion strengthening, phonon scattering, tribochemical film formation, and the development of multicomponent oxide scales—are discussed. Current limitations are identified, particularly the lack of quantitative composition–structure–property relationships and insufficient understanding of high-temperature service behavior. Future efforts should focus on mechanism-guided compositional design integrating computational and experimental approaches.

This work systematically investigates the effects of Cr and V elements on the microstructure, grain size, and properties of TiN-based coatings prepared by reactive plasma spraying (RPS). Thermodynamic calculations were conducted to assess the feasibility of the reaction. The phase composition and microstructure of the coatings were analyzed using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Their mechanical, wear and corrosion resistance properties were tested using a microhardness tester, a friction and wear testing machine, and an electrochemical workstation. The experiments successfully produced ternary nitride coatings primarily composed of face-centered cubic (FCC) structures. After etching agent treatment, it was found that the internal structures of all three coatings consisted of dense equiaxed grains, closely packed columnar grains, and dendritic grains. The addition of V significantly refined the grain size to 20-50 nm and formed high-density nanotwins and dislocations. The grain size of the (Ti,Cr)N coating is comparable to that of TiN. Performance testing indicates that the (Ti,V)N coating exhibits the highest microhardness, reaching 2054 HV0.1, significantly exceeding that of TiN (1120.5 HV0.1) and (Ti,Cr)N (1230.7 HV0.1). its coefficient of friction was the lowest (0.4134), with wear volume and wear rate of 0.4025 mm3 and 3.72 x 10-4 mm3/N & sdot;m, significantly superior to TiN (1.4627 mm3, 1.35 x 10-3 mm3/N & sdot;m) and (Ti,Cr)N (0.8231 mm3, 7.71 x 10-4 mm3/ N & sdot;m). In a 3.5 % NaCl solution, the corrosion current density of (Ti,Cr)N and (Ti,V)N coatings is one order of magnitude lower than that of TiN coatings. This study proposes that the atomic size difference between the dopant elements and Ti, as well as the reactivity of the nitridation process, are key factors influencing grain size in RPS nitride systems, providing a technical pathway and theoretical basis for developing novel wear-resistant and corrosion-resistant coatings.

High-entropy diboride ceramics are renowned for their exceptional mechanical properties, yet there remains a critical gap in the understanding of their high-temperature friction and wear performance when deployed as protective coatings. In this paper, a novel nano high entropy (ZrNbTiCrMo)B2-SiC coating was successfully prepared through a multi-step process involving boron carbide thermal reduction, spray drying and plasma spraying process. First-principles calculations were adopted to predict the feasibility of (ZrNbTiCrMo)B2 phase formation and its lattice parameters. The results demonstrate that SiC enhanced the microhardness and fracture toughness of the coating by approximately 20% and 30%, respectively. This improvement was achieved via densification of the microstructure, grain refinement, inhibition of Cr element segregation, and grain boundary strengthening. Specifically, from room temperature up to 900 degrees C, the friction coefficient and wear rate of the (ZrNbTiCrMo)B2-SiC coating were observed to decrease with rising temperature, attaining their minimum values of 0.32 and 5.07 x 10-5 mm3/(N & sdot;m) at 900 degrees C, respectively. These findings indicate typical high-temperature self-lubricating characteristics. At room temperature and 300 degrees C, the (ZrNbTiCrMo)B2-SiC coating was dominated by abrasive wear. At 600 degrees C and 900 degrees C, a mixed wear mechanism consisting of abrasive wear and oxidative wear was observed. The further decrease in wear rate at 900 degrees C stemmed mainly from the formation of shear-resistant dense oxide film, which consisted of composite nano-oxide particles encapsulated by borosilicate glass.

High-entropy carbide (HEC) coatings are promising for extreme environments, but their tribological performance and the effect of individual elements remain insufficiently understood. This study deposited (ZrNbTiCr)C and (ZrNbTiCrV)C coatings via plasma spraying and systematically compared their microstructure, mechanical properties, and frictional behavior. Adding V increased microhardness by 7.5 % but reduced toughness by 9.1 % and weakened structural integrity. Results revealed that the introduction of V weakens the interatomic bonding and reduces stability, which in turn leads to the oxidation of V to V2O5, which disrupted coating continuity and interfacial cohesion, serving as preferential sites for crack initiation and propagation. The (ZrNbTiCrV)C coating showed higher porosity with unmelted particles and oxidized segregations. The wear rate of the V-containing coating was approximately 1.8 times higher than that of its V-free counterpart. During sliding wear, the (ZrNbTiCr)C coating exhibited stable friction dominated by fatigue and oxidative wear, while the (ZrNbTiCrV)C coating showed higher, erratic friction coefficients with rapid failure due to mechanical delamination caused by numerous microscopic defects. From a tribological perspective, this work clarifies the detrimental role of vanadium and provides a guideline for designing wear-resistant HEC coatings by controlling the content of elements that form unstable oxides.

Zirconium boride composite coatings were synthesized in situ using atmospheric plasma spraying process with ZrO2-B4C-Al as precursor, and ZrB2-ZrC-Al2O3 composite coatings were prepared as a comparison, and the microstructures and thermal shock and ablation resistance of the two systems of composite coatings were studied comparatively. The results showed that the ZrO2-B4C-Al system composite coating had higher density and ultra-fine microstructure, and this coating had better thermal shock resistance, which is mainly due to the reaction between the composite powders during the in-situ formation process of the coating, resulting in higher density and more stable phase structure. In the ablation test, a large amount of Al4B2O9 was formed on the surface of the ZrB2-ZrC-Al2O3 composite coating, which played the role of stabilizing the liquid phase and covered the surface of the coating to prevent the diffusion of oxygen, and the crystals grew and arranged preferentially to form a large-grained spherical oxidized eutectic phase as well as a solid solution of alumina and zirconia, so that the coating showed excellent ablation-resistant properties.

In this study, we successfully prepared NiCrBSi-TiCrN composite coatings containing Cr-rich transition phases at the grain/phase boundary by using plasma spraying technology and compositional adjustment strategies. We thoroughly explored the impact of Cr-rich transition phases on the wear performance of the composite coatings. The phase composition and microstructure were characterized by XRD, SEM and TEM techniques, the wear behavior of the coatings was tested by reciprocating friction and wear tester, and the accuracy and reliability of the experimental results were verified with FEA tools. Results revealed that a Cr-rich transition phase was formed at the interface between the Ni-based alloy phase and the TiCrN ceramic phase, as well as at the TiCrN grain boundaries, which was attributed to the different solidification times of the physical phases with the increase of the Cr content in the Ti/Cr ratio. Grain/phase boundary Cr-rich transition phase significantly improves abrasion performance of the composite coating, improves ceramic phase toughness and alleviates stress concentration phenomenon within the coating during wear, improves the anti-cracking and anti-peeling properties to ensure effective reinforcement of NiCrBSi composite coatings by TiCrN ceramics. The results of the study are significant for optimizing the coating composition and structure design, and developing high-performance, long-endurance metal-based ceramic composite coating materials.

This work used the in-situ synthesis of molten-state nitride ceramic phase-reinforced Ni-based alloy coatings, aiming to improve the phase-interface bonding through the interdependent co-solidification between molten droplets. The XRD was used to analyze the physical phases of the composite coatings. The microstructure and phase-interface structure were characterized in detail by combining SEM, TEM, HRTEM, FFT, and SAED techniques. Microhardness tester and microforce microhardness tester were employed to measure the surface hardness and elastic modulus of the composite coatings. The fracture behavior of the composite coatings was characterized by observing the fracture morphology of the coatings using SEM combined with the EDS technique. It was found that the formation mechanisms of interfacial misfit dislocation assistance, lattice distortion, aggregation of stacking faults, and specific growth orientation between the γ-Ni matrix phase and each ceramic phase in NiCrBSi-TiCrN composite coatings improved the lattice matching between the two-phase interface, which resulted in the formation of atomically corresponding coherent lattice relations and stepped interfacial semi-coherent lattice relations, and enhanced the degree of phase-interface bonding. On this basis, the composite coatings with high Cr content further inhibited the expansion of interphase penetration cracks due to the existence of Cr-rich zones at the phase interface, thus exhibiting high fracture toughness. This work provides new opinions on the improvement of phase-interface bonding and composition design of Ni-based composite coatings.

The effects of service environment temperature (25, 550, 650, 700, and 750 °C) on the friction and wear properties of (Ti, Cr, V) N composite coatings were investigated. The structure and phase of the coating before and after wear at wide temperature ranges were analyzed by scanning electron microscopy, XRD, transmission electron microscopy, and Raman spectroscopy. A wide temperature range wear test was carried out at room temperature, 550, 650, 700, and 750 °C for 20 min using a reciprocating friction and wear tester. The results show that the (Ti, Cr, V) N composite coating overcomes the shortcomings of single nitride, which is the initial oxidation temperature is low in a wide temperature range. The surface oxides produced at 25-750 °C have an important influence on the wear behavior and wear resistance. At room temperature and 550 °C, the main phase of the coating is the TiCrVN hard phase, which can reduce the wear rate of the coating at room temperature. At higher temperatures of 700 and 750 °C, dense oxide hard films of Cr2O3, TiO2, V2O5, and TiVO4 formed on the wear scar surface play a key role during friction and wear. 650 °C is a critical temperature for wear behavior change. The mechanical properties of the coatings at 700 and 750 °C are significantly higher than those at 650 °C, and HIT3/E*2 is increased by 76

Against the backdrop of increasingly fierce technological competition, the innovative development of materials science is of vital importance. As the backbone of the future of the discipline, graduate students’ innovative abilities are of great concern. Tutoring styles, as a key factor, have an urgent need for in-depth exploration of their impact on the innovative abilities of graduate students in materials science. This study focuses on the impact of tutoring styles on the innovative abilities of graduate students in materials science. By combing through relevant literature and conducting practical surveys and analyses, the study explores the characteristics of different tutoring styles and their mechanisms of action on graduate students’ innovative thinking, practical abilities, and other aspects. The study finds that scientific and rational tutoring styles can significantly enhance the innovative abilities of graduate students in materials science, providing theoretical basis and practical references for optimizing tutoring strategies and improving the quality of graduate student training.

In the family of diamond-like carbon (DLC) coatings, hydrogen-containing DLC demonstrates significantly enhanced corrosion resistance, exceptional self-lubrication characteristics, and superior tribological properties relative to conventional coatings under harsh operational conditions. Hydrogen-containing DLC coating imparts the steel matrix with resistance to humid environments and seawater, while enhancing wear resistance, thereby extending service life. Therefore, investigating the impact of hydrogen concentration on the corrosion resistance of DLC is warranted. Such research would also facilitate its application in domains necessitating the concurrent optimization of both corrosion protection and lubrication properties. In this study, DLC coatings with different hydrogen content were prepared on alloy steel surface by changing the flow rates of hydrogen in the reactive gas source in plasma-enhanced chemical vapor deposition (PECVD). With the increase of hydrogen flow, the hydrogen content of DLC coating increases from 13.5 at.% to 23.6 at.%, the disorder degree of DLC increases gradually, and the size and quantity of sp2 cluster decrease gradually. Meanwhile, pitting corrosion is the main corrosion type of DLC coatings. With the increase of hydrogen content in DLC coating, the DLC coatings become denser, and the corrosion resistance of DLC coating was improved.

To study the corrosion behavior of high-entropy alloy coatings in alkaline solutions, FeCoNiCrMnAl0.5 and FeCoNiCrMnAl1.0 powders were prepared by mechanical alloying, and their coatings were coated on the surface of 316L stainless steel by plasma spraying technology. The corrosion resistance of the coatings in 1.0 mol/L NaOH solution was tested using an electrochemical workstation. The FeCoNiCrMnAl0.5 coating consists of a dual phase of FCC phase and Al2O3 phase, and the FeCoNiCrMnAl1.0 coating consists of FCC phase, BCC phase, and Al2O3 phase. In 1.0 mol/L NaOH solution, both coatings showed an obvious passivation phenomenon. The corrosion current densities of FeCoNiCrMnAl0.5 coating and FeCoNiCrMnAl1.0 coating were 1.006 x 10-5 A/cm2 and 7.051 x 10-6 A/cm2, respectively, and the corrosion potentials were-0.5277V and-0.5116V, respectively, which were higher than that of the corrosion potential of 316L stainless steel of-0.6572 V. The corrosion rates were 0.529 mg/(cm2/h) and 0.671 mg/(cm2/h), respectively, both lower than the corrosion rate of 316L stainless steel of 0.878 mg/(cm2/h).

In the present study, (Ti,Nb)N-based composite coatings with a thickness of 250 μm are prepared using reactive plasma spraying technology, and the effect of Nb content on structure, conductivity, and corrosion resistance is investigated. The (Ti,Nb)N-based composite coatings with a crystal size of 40-200 nm have multi-layered structures, and each layer is composed of NbTiN2, Ti3O, and Nb. As the Nb content increases, the density of the coating increases, and the Nb-30 wt.