等离子喷涂碳化铬－镍铬涂层的摩擦学特性

Tribological Properties of Plasma Sprayed Chromium Carbide-Nickel Chromium Coating

在发展新型高效节能的汽车和飞机发动机用耐磨材料中，碳化铬－镍铬涂层是很有开发前景的材料之一．为了扩大这种涂层的应用领域并为其应用提供科学依据，用ＭＭ－２００磨损试验机，研究了等离子喷涂碳化铬－镍铬（质量比为３∶１）涂层分别与不锈钢、热压烧结Ｓｉ３Ｎ４和石墨组成摩擦副的摩擦学特性；用扫描电子显微镜、Ｘ射线能量色散谱仪和Ｘ射线衍射技术，考察了磨痕和磨屑的形貌、元素分布和物相组成；讨论了涂层分别与给定的３种材料配副时的磨损机理．结果表明：涂层与不同材料对摩时的磨损量差别很大，磨损机理也明显不同——涂层与不锈钢对摩时的磨损表现为层状颗粒的断裂与剥离；涂层与Ｓｉ３Ｎ４对摩时的磨损主要表现为涂层颗粒的断裂和断裂颗粒的脱碳氧化；

Chromium carbide-nickel chromium coating has been found to be one of the most promising materials for wear resistance in automobile and aircraft engine with high rate of work and efficiency.In order to extend the application fields of the coating and give a theoretical bases for its applications,the sliding friction coefficients and wear mass losses of plasma sprayed chromium carbide-nickel chromium coating against stainless steel,hot-pressing sintered Si 3N 4,graphite were measured using a MM-200 wear tester.The morphology,element distribution and phase structure of worn tracks and debris of counterpart materials were examined employing the SEM,EDAX and XRD respectively.The wear behavior and wear mechanism of the coating against the three materials were discussed.The results obtained showed that the wear mass losses of the coating against the three materials change apparently.The wear of the coating against stainless steel is explained in term of spalling and fracturing.The wear of the coating against Si 3N 4 is due to the particles fractere of the coating and the decarbonization and oxidation of the fractured particles.Graphite,however,acts as a solid lubricant and improves the wear resistance of the coating.