可磨耗封严涂层的冲蚀磨损特性及模型

 抗冲蚀性是可磨耗封严涂层最重要的性能。在自制的真空自由落砂试样旋转式冲蚀磨损试验机上对几种中温封严涂层的冲蚀磨损特性及机理进行了研究。实验结果表明，冲蚀失重与冲蚀时间具有良好的线性关系；在60°时冲蚀率最大；冲蚀率与冲蚀速度有幂函数关系，速度指数随冲蚀角度增大而增大；90°冲蚀时，涂层的冲蚀机理为冲击粒子在涂层表面冲击挤压，产生凹坑和凹坑边缘凸起的唇片，随后的冲蚀使唇片流失；粒子的不断冲击使表层金属相松动，导致呈颗粒状剥落。30°冲蚀时涂层的冲蚀机理为切削、犁削并有孔洞、非金属相贯通效应。在此基础上提出了封严涂层的冲蚀磨损模型。

EROSION WEAR BEHAVIOUR AND MODEL OF ABRADABLE SEAL COATING

The erosion wear resistance is one of the most important properties of abradable seal coating. The erosion wear behaviour and mechanism of several kinds of middle temperature abradable seal coatings were investigated by a CMS 100 self made vacuum sand erosion machine. The results show that the relationship between the erosion weight loss and the erosion time is linear, the coatings hold a maximum erosion rate at 60° impact angle, and the relation between the erosion rate and the impact speed is an exponential function. The speed exponent increases with the increase of the impact angle. At 90° impact, the abrasive particles impinging on the coating surface produce indents and extrude lips, then the lips are work hardened and fall off; and flattened metal phase grains are impinged repeatedly, loosen and exfoliate. At 30° impact, the micro cutting, plowing and tunneling via pores and non metal phase are involved. The model of the erosion mechanism is advanced on the basis of the above mentioned erosion behaviour.