(1. 中国兵器科学研究院 宁波分院，宁波 315103；
2. 中国科学院 兰州化学物理研究所，固体润滑国家重点实验室，兰州 730000)
摘 要: 为了提高运动部件在宽温域(尤其是高温)条件下的润滑和耐磨性能，采用大气等离子喷涂(APS)技术在不锈钢基材上喷涂制备了三种Ag含量分别为0、10%和30%(质量分数)的NiMoAl-Ag固体自润滑涂层。利用扫描电子显微镜、Ｘ射线衍射仪、CSM摩擦磨损试验机、三维光学轮廓仪等设备，对涂层的组织结构和在20~800 ℃时的摩擦磨损机制进行了分析。结果表明：NiMoAl-Ag涂层呈现致密的显微结构和均匀的组份分布；NiMoAl-Ag涂层在20~800 ℃时的摩擦因数随着Ag含量的增加而显著下降，含有30%Ag的NiMoAl-Ag涂层在800 ℃的摩擦因数降至0.12。但是，Ag含量的增大会降低涂层在20~400 ℃的耐磨性；当温度进一步升高到600 ℃和800 ℃时，Ag的加入却可以明显提高涂层的耐磨性。进一步分析涂层的润滑机理表明：涂层中的Ag含量增大可以在高温摩擦界面形成液态Ag和Ag2MoO4润滑釉质层的协同润滑作用，使得涂层具有较低的摩擦因数和磨损率。APS制备的NiMoAl-Ag涂层具有优良的宽温域自润滑性能，通过复配合适的增强相有望提高其中低温耐磨性能，是一种极有潜力的新型宽温域耐磨自润滑涂层材料。
关键字: 大气等离子喷涂；NiMoAl；Ag；自润滑；宽温域；润滑机理
（1. Ningbo Branch of Chinese Academy of Ordnance Science, Ningbo 315103, China;
2. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China）
Abstract:This work aims to satisfy the urgent need for materials that possess good lubrication and wear resistance under the wide temperature range (especially high temperature) for many industrial moving parts. Three kinds of NiMoAl-Ag solid lubricating coatings were prepared on stainless steel substrate by atmospheric plasma spraying (APS), using the composite powders that contained 0%, 10% and 30% Ag in mass fraction as feedstock powders. Scanning electron microscope (SEM), X-ray diffractometer (XRD), CSM tribometer and 3D optical profiler were used to evaluate the microstructure and tribological properties of as-sprayed coatings at temperatures from 20 ℃ to 800 ℃. The experimental results show that friction coefficients of NiMoAl-Ag coating decreases significantly with the increase of Ag content, and the coating containing 30% Ag has the lowest friction coefficient of 0.12 at 800 ℃. However, the increase of Ag content reduces the wear resistance of the coating at 20-400 ℃. When the temperature further increases to 600 ℃ and 800 ℃, the addition of Ag can obviously reduce the wear volume of the coating. Further analysis of the lubrication mechanism indicates that when the Ag content in the coating increases, the synergistic lubrication effect of liquid Ag and molybdate silver lubricating enamel layer can be formed at the high temperature friction interface, so that the coating has low friction coefficient and wear rate. Therefore, NiMoAl-Ag composite coating prepared by APS has excellent self-lubricating properties in wide temperature range. It is also expected that the suitable reinforcement phase may greatly improve its low temperature wear resistance, thus NiMoAl-Ag coating is a potential new wear-resistant and self-lubricating coating material in wide temperature range.
Key words: atmospheric plasma spraying; NiMoAl; Ag; self-lubricating; wide temperature range; lubrication mechanism
