40Cr钢离子氮化与离子镀TiN复合涂层与苜蓿草粉之间的摩擦学特性

Tribological Property of Ion Nitriding and Ion Plating TiN Composite Coating on 40Cr Substrate by Alfalfa Powder

在橡胶轮磨料磨损实验机上考察了40Cr钢基体上离子氮化与离子镀TiN复合涂层在苜蓿草粉软磨料下的摩擦学特性。采用划痕法测定了涂层的结合力,利用XRD分析了涂层的相结构,应用扫描电子显微镜观察分析了涂层磨损表面形貌和磨损机理。结果表明:离子氮化与离子镀TiN复合涂层的膜基结合力和硬度均高于TiN涂层;其对于苜蓿草粉软磨料的耐磨性也高于TiN涂层和渗氮层;离子氮化过渡层能显著提高TiN涂层的膜基结合力并改善薄膜的韧性;涂层能有效限制硬质颗粒对基体的压嵌和切削。涂层在苜蓿草粉软磨料下的磨损机制既包括硬质颗粒磨料条件下的切削磨损,也包括软磨料条件下的多次塑性变形和周期疲劳磨损。涂层硬度和韧性的共增可以提高其对软磨料的耐磨性。

The tribological property of ion nitriding and ion plating TiN composite coating on 40Cr substrate sliding against alfalfa powder was investigated on an abrasive rubber wheel tester. The adhesion strength and phase structure of the TiN coating were examined by means of scratch test and X-ray diffraction. The morphologies of the worn surfaces of TiN composite coating and wear mechanism were observed and analyzed by mean of scanning electron microscopy. The results showed that the adhesion strength and hardness of TiN composite coating with ion nitriding interlayer are higher than that of TiN coating. The wear resistance of TiN composite coating is higher than that of TiN coating sliding against alfalfa powder. Ion nitriding interlayer enhanced adhesion strength and toughness of the coating. Coating helped to avoid any further penetration into the base material. The wear mechanism of coating under the soft abrasive of alfalfa meal include both the cutting wear under the condition of hard abrasive particles, and many plastic deformations as well as periodic fatigue wear under soft abrasive conditions. The increase in hardness and toughness of coating at the same time can improve its wear resistance to the soft abrasive.