TiN/Ti强韧涂层在砂尘高速冲蚀下的失效机理

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。 

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

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.