Ni60/铝青铜喷涂后定向凝固涂层的微观结构与耐磨性

Microstructure and Friction Properties of Directional Solidification Coatings Formed by Ni60/Aluminium Bronze after Spraying

目的为有效提高涂层的耐磨性能,提出制备定向结构复合涂层,通过评估其性能及结构特征,探索定向结构在涂层制备中的应用。方法以Ni60/铝青铜为研究对象,采用感应重熔+强制冷却技术对预制涂层进行处理,制备定向凝固复合涂层。借助销盘式摩擦试验机、OM、SEM、XRD、显微硬度计对其摩擦学行为、微观组织形貌、显微硬度进行表征研究。结果摩擦磨损试验表明,相对于预制涂层,在载荷分别为50、100、150 N时,重熔涂层的体积磨损率分别降低了85%、80%、82%,而定向凝固涂层的体积磨损率分别降低了93%、84%、86%,定向凝固涂层具有更好的耐磨性能。微观结构分析表明,重熔涂层和定向凝固涂层与基体均形成了牢固的冶金结合,而定向凝固涂层组织基本控制了晶粒沿着热流方向生长,并形成硬质相包裹枝晶的裹壳结构。定向凝固涂层随载荷的升高,摩擦系数保持稳定。结论通过感应重熔+强制冷却技术制备了定向凝固Ni60/铝青铜复合涂层,其定向结构的形成使涂层具有更加优越的耐磨性能。

To improve the wear resistance of coatings effectively,prepare the directional solidification composite coatings and explore the application of directional structure in coating preparation by evaluating performance and structural characteristics.Ni60/aluminum bronze was taken as the research material,the directional solidification composite coatings were prepared by induction remelting+forced cooling technology.The tribological behavior,microstructure morphology and microhardness were characterized by pin plate friction testing machine,OM,SEM,XRD and microhardness tester.The friction and wear test showed that,compared with prefabricated coatings,when the load was 50,100 and 150 N,the volumetric wear rate of the induction remelting coating was decreased by 6.7 times,5 times and 6.5 times,while that of the directional solidification coating was reduced by 12.9 times,6.8 times and 7.5 times.Therefore,the directional solidification coating had better wear resistance.The microstructure analysis showed that the strong metallurgical bond was formed in the remelting coating and the directional solidification coating,and the directional solidification coating controlled the growth of the grain along the direction of heat flow,and formed the shell structure of hard phase wrapping the dendrites.The directional solidification coating exhibited stable friction coefficients along with the elevated loads.The directional solidification Ni60/aluminum bronze composite coating is prepared by induction remelting+forced cooling technology,and the formation of directional structure makes the coating have better wear resistance.