CoNiCrAlY黏结层结构设计及其对热障涂层结合强度和抗热震性能的影响

目的 设计热障涂层黏结层结构,改善涂层结合强度和抗热震性能。方法 制备了5种结构的CoNiCrAlY黏结层,即超音速火焰喷涂(HVOF)底层+等离子喷涂(APS)上层的双层结构黏结层试样,对其进行1 050℃真空热处理3 h后的试样,APS黏结层试样,HVOF黏结层试样及其真空热处理试样。再在以上5种试样表面制备Y₂O₃部分稳定ZrO₂(YSZ)陶瓷层,研究黏结层的表面粗糙度、相组成、微观组织结构及其对涂层试样结合强度、热震性能的影响。结果 制备态的黏结层由γ/γ’和β-NiAl两相组成,真空热处理后β相含量增多,表面粗糙度下降。在所有涂层试样中,双黏结层的涂层试样的结合强度最低,为28.43 MPa;对其真空热处理后得到的涂层试样的结合强度最高,达到39.42 MPa,主要原因在于热处理促进了两黏结层之间的扩散,提高了界面强度。双黏结层的涂层试样的抗热震性能最好,200次热震后涂层无明显剥落,而APS黏结层的涂层试样的抗热震性能最差,涂层抗热震性能的差异在于黏结层微观结构的不同。结论 双黏结层的结构设计综合了APS、H...

Microstructure Design of CoNiCrAlY Bonding Coating and Its Influence on the Bonding Strength and Thermal Shock Resistance of Thermal Barrier Coatings

Thermal barrier coatings (TBCs) have advantages of decreasing the surface temperature of aero-engine blades, improving oxidation resistance of blades, prolonging blades service lifetimes, and reducing fuel consumption of engines, which have been widely used for decades. A typical TBC system is composed of a metallic bond coat and a ceramic top coat. The former is usually made of MCrAlY (M:Ni, Co or Ni+C) and PtAl, and the latter is made of Y2O3 partially stabilized ZrO2 (YSZ). Metallic bond coats can be prepared by high velocity oxygen-fuel (HVOF) or atmospheric plasma spraying (APS) methods. APS bond coats have rough surfaces and good adhesion to the ceramic top coat, but their porosities are high and the cohesive force is relatively, while the HVOF ones have dense microstructure, excellent oxidation resistance, good adhesion to the substrate, but the surface roughness is low and the adhesion to the ceramic top coats is not high enough. Before, the preparation of ceramic top coats, the substrates with bond coats need vacuum heat treatment, which could promote to formation a thermally grown oxide (TGO) layer on the bond coat leading to enhanced oxidation resistance and interface bond strength. Usually, it is considered that the abnormal growth of the TGO layer is a key factor causing TBCs failure.