TiN/Ti强韧涂层在砂尘高速冲蚀下的失效机理

Failure mechanism of TiN/Ti strength and tough coating under high-speed sand-dust erosion

利用高速连续冲蚀试验系统,在不同的冲击角及供砂量下,对有无TiN/Ti强韧涂层的不锈钢试件进行了砂尘高速冲蚀试验,获得了试件的质量冲蚀率。采用扫描电镜(SEM)对涂层损伤表面及断面形貌进行观测与分析,研究TiN/Ti涂层在不同冲击条件下的失效机理。结果表明:TiN/Ti涂层质量冲蚀率随冲击角及供砂量的增加而增加。在低冲击角下,砂尘粒子的切削作用是导致涂层材料剥落的主要原因;高冲击角下,砂尘冲击引起的裂纹萌生及扩展致使涂层材料块状破碎而剥落。TiN/Ti涂层显著提高了不锈钢的抗冲蚀性能,尤其是在低冲击角下。低冲击角下,涂层能将不锈钢的冲蚀性能提高约5倍;高冲击角下能提高约2倍。

Through high-speed continuous erosion test system,high-speed sand-dust erosion tests of stainless steel specimens with or without TiN/Ti strength and tough coating were carried out at different impact angles and sand supplies,and the mass erosion rates of specimens were obtained.The surface and cross-sectional damage morphology of the coating were observed by scanning electron microscopy(SEM),and the failure mechanism of TiN/Ti coatings under different impact conditions was analyzed.The results show that the mass erosion rate of TiN/Ti coatings increases with the increase of impact angle and sand supply.At low impact angle,the cutting action of sand particles is the main reason for the spalling of coatings;at high impact angle,the crack initiation and propagation caused by sand-dust impact lead to massive fragmentation and spalling of coatings.TiN/Ti coating can significantly improve the erosion resistance of stainless steel,especially at low impact angle.At low impact angle,the erosion resistance of stainless steel with coating can be increased by about 5 times,and at high impact angle it can be increased by about 2 times.