冷阴极离子镀TiN薄膜的空蚀磨损特性研究

Cavitation-Erosion Behavior of Cold-Cathode-Ion-Plated TiN Coating

采用自制磁致伸缩式空蚀磨损试验机考察了冷阴极离子镀TiN薄膜的空蚀磨损性能,分析了TiN镀层的空蚀磨损过程及机理,探讨了TiN镀层硬度和厚度对其空蚀磨损性能的影响.结果表明:TiN镀层具有优异的抗空蚀磨损性能;其空蚀磨损过程可以划分为孕育、镀层磨损、混合磨损及基体磨损等4个阶段;空蚀磨损从软质点开始,软质点剥落形成凹坑,凹坑边缘发生剥落或断裂;TiN镀层的抗空蚀磨损性能随其硬度和厚度增加而提高.

The cavitation-erosion performance of TiN film plated on AISI-1045 steel substrate by cold cathode ion plating was investigated on a magnetostrictive cavitation-erosion tester. The cavitation-erosion process and mechanism were analyzed, and the influence of the hardness and thickness of the TiN coating on the cavitation-erosion performance was explored. It was found that the ion-plated TiN coating has much better resistance to cavitation-erosion and was thus applicable to protect the mild steel from the cavitation-erosion. The cavitation-erosion resistance of the TiN coating increases greatly with the increase of hardness and thickness, but the dependence of the cavitation-erosion resistance on the coating thickness becomes margin when the coating thickness rises above 4.5 μm. The cavitation-erosion of the TiN coating initially occurs at the surface defects such as the soft particles and micro-cavities, and it progresses into weak particle peeling off, concave formation, delamination, and localized fracture, corresponding to the four stages of the cavitation-erosion.