等离子喷涂-物理气相沉积防护涂层及其失效机理研究进展

Research Progress on Plasma Spray-Physical Vapor Deposition Protective Coatings and Their Failure Mechanisms

摘要:

防护涂层在航空发动机和燃气涡轮发动机免受水氧腐蚀和盐雾侵蚀、耐高温、抗冲刷和服役寿命方面发挥着重要的作用。等离子喷涂-物理气相沉积（PS-PVD）技术以其大功率、喷射范围广、能够使粉末原料以气相甚至离子化和非视线沉积特性等特点被广泛应用在热/环境障涂层制备领域，形成的涂层具有沉积效率高、孔隙率较高、热导率低、应变容限高等特点。首先，对PS-PVD热障涂层的表面形貌、柱状晶特点和等离子射流特性进行了探讨。然后，讨论了PS-PVD YSZ热障涂层表面镀铝改性对涂层抗CMAS侵蚀、减少孔隙和裂纹、TGO的生成和提高热循环寿命方面的重要作用，结果表明表面镀铝能显著减少涂层表面孔隙、凹坑、微裂纹和熔融盐对于热障涂层的不利影响。其次，简要概述了近年来SiC_f/SiC CMCs代替镍基高温合金在航空发动机基体上抗高温高压和快速失效方面发挥的重要作用。SiC_f/SiC CMCs与T/EBCs的结合，有效延长了航空发动机的使用寿命，是我国航空事业的又一次重大突破。此外，重点介绍了PS-PVD非视线沉积特性和涂层阴影效应在涂层沉积方面这一特色，总结了TGO、残余应力、热膨胀失配、微裂纹和粗糙度是涂层失效的主要影响因素。最后，对PS-PVD技术未来在制备热/环境障涂层方面的前景进行了展望。

Abstract:

Protective coatings play an important role in aero-engines and gas turbine engines for the protection from water-oxygen corrosion and salt spray corrosion， high temperature resistance， erosion resistance and service life. Plasma Spraying-Physical Vapor Deposition （PS-PVD） technology is widely used in the field of thermal/environmental barrier coating preparation due to its high power， wide spray range， capability to gasify or even ionize powder feedstock materials and non-line-of-sight deposition characteristics. The deposited coatings have the characteristics of high deposition efficiency， high porosity， low thermal conductivity， and high strain tolerance. In this review， the surface morphology， columnar crystal characteristics and plasma jet characteristics of PS-PVD thermal barrier coatings were first discussed. Then， the important effect of aluminum plating modification on the surface of PS-PVD YSZ thermal barrier coatings on the corrosion resistance of CMAS erosion， the reduction of pores and cracks， the generation of TGO and the improvement of thermal cycle life is discussed. The results show that the surface aluminum plating can significantly reduce the adverse effects of porosity， pits， microcracks and molten salts on the coating surface on thermal barrier coatings. Second， a brief overview of the important role played by SiC_f/SiC CMCs in replacing Ni-based superalloys in the resistance to high temperature and high pressure and rapid failure on aero-engine substrates in recent years is given. The combination of SiC_f/SiC CMCs and T/EBCs effectively prolongs the service life of aero-engines， which is another major breakthrough in our country's aviation industry. In addition， the characteristics of PS-PVD non-line-of-sight deposition characteristics and coating shadow effect in coating deposition are highlighted. It is concluded that TGO， residual stress， thermal expansion mismatch， microcracks and roughness are the main influencing factors of coating failure. Finally， the future prospects of PS-PVD technology in the preparation of thermal/environmental barrier coatings are prospected.