本文采用普通等离子喷涂(APS)与高效能超音速等离子喷涂(SAPS)两种工艺在2Cr13基体上制备75wt.％Ni+25wt.％石墨(Ni-C)可磨耗封严涂层,对涂层的摩擦学性能进行评价.结果表明:APS Ni-C涂层中石墨相的平均长度与宽度分别为11.4μm和5.4μm,而SAPS Ni-C涂层则分别为10.1μm和4.6μm,且分布更为均匀.石墨相尺寸对涂层性能具有显著的影响作用,表现为细小的石墨相更利于在涂层表面形成石墨润滑膜,使得SAPS涂层在60N载荷下与1Cr18Ni9Ti对磨90min过程中平均摩擦因数与APS涂层相比下降约28％,对磨材料1Cr18Ni9Ti单位时间磨损率降低了57％.

The development of long-lifetime and high-performance thermal barrier coatings (TBCs) has been a very urgent task due to the need of high-power aero-engines and new-generation supersonic air craft. The failure caused by the penetration of CaO-MgO-Al2O3-SiO2 (CMAS) has been given more and more attention during recent years. This paper reviewed the latest experimental results on the failure mechanism and corrosion resistance of coatings deposited by atmospheric plasma spraying (APS) or electron beam physical vapor deposition (EBPVD) with the aim of fabricating the high-performance TBCs.

The low thermal cycling life is a big concern for plasma sprayed thermal barrier coatings (TBCs). This paper presents a novel and effective preheating treatment conducted by one supersonic plasma jet, which has been proven to significantly improve the anti-oxidation and thermal shock resistance of TBCs. After preheating treatment, the surface roughness (Ra) of metallic bond coat decreased by nearly 30%, while one dense oxide layer appeared on its surface. This oxide layer effectively suppressed the growth of thermally grown oxides (TGOs), resulted in the improvement of anti-oxidation of TBCs. The results of water-quenching test from 1100°C into room temperature showed that the thermal cycling life of preheated TBCs reached 846 cycles, approximately 126 cycles higher than their counterparts without preheating.

This paper aims to elaborate the particle in-flight behavior during plasma spraying and its significance in determining the microstructure and mechanical properties of La2Ce2O7 (LC) coatings. One Box-Behnken Design (BBD) method was applied to analyze the effect of spray parameters on average velocity and temperature of in-flight particles during spraying. LC coatings were characterized in terms of the microstructure, hardness and fracture toughness. It was found that the argon flow rate was the most important parameter that influenced the velocity of particles, however the main factors of affecting the particles temperature was the hydrogen flow rate. The improvement of melting index of in-flight particles increased the lattice parameters of as-sprayed coatings while decreased defects (unmelted particles, pores and cracks). Decreasing defects resulted in increasing hardness and elastic modulus of the coatings. However, the fracture toughness of coatings maximized at the content of defects reached approximately 9.4%.

This paper aims to improve the anti-oxidation and thermal cycling life of thermal barrier coating system (TBCs) by tailoring the microstructure of MCrAlYbond coat. The cobalt-based and nickel-basedbond coats were deposited byhigh efficiency supersonic atmospheric plasma spraying (SAPS) system. The microstructures of bond coats were optimized by ahigh-temperature oxidation test. A comparative study between SAPS-coating and HVOF-coating (high velocity oxygen fuel spraying, HVOF) was conducted in order to analyze the microstructure-property differences between them. The results showed that the SAPS-coatings that remained 35%± 5%(cobalt-based) and 10%± 3%(nickel-based) unmelted particles exhibited the best oxidation resistance. For the same composition of bond coat and microstructure of top coat, the thermal cycling life of SAPS-coating was two times as much as that of HVOF-coating, however, the average growth rate of thermally grown oxides (TGOs) was reduced by more than 20%. The SAPS can“one-step” deposit the bond coat and top coat , whicheffectively avoids the pollution resulted from the so-called “two-step”process method. With the advantages of simple process, high deposition efficiency and low production cost, the SAPS method shows a good industrial prospect.

The bond coatings were fabricated by Supersonic plasma spraying with NiCoCrAlY, the conventional and nano-structured YSZ thermal barrier coatings (TBCs) were prepared by Atmosphere plasma spraying(APS), the microstructure evolution laws of two different TBCs were compared under the thermal cycle conditions. The results show that there is lots of microcrack in the nano-structured coating with 15% void content because of incomplete melding of agglomerated nanopowder, while the void content of conventional coating is 10%. Under the loading of 300g, the micro-hardness of nano-structured coating is 776.1 and that of conventional coating is 606.9. Resillage appeared in these two coatings during the thermal cycle process and connected with each other as the number of cycles increasing, the width of crack was extended finally. Compare with nano-structured coating, the crack in conventional coating extended and broadened faster. Thermally grown oxide(TGO) in nano-structured coating grows faster because of the higher void content, then the stress between top coating and bond coating increasing, transverse crack ( parallelling with the interface between top coating and bond coating) appeared and extended, eventually resulted in coating failure with spalling.