超音速火焰喷涂CoCrAlYSi-hBN涂层组织和性能

The microstructure and properties of CoCrAlYSi-hBN coating prepared by HVOF

采用超音速火焰喷涂(HVOF)方法制备CoCrAlYSi-hBN涂层,通过对涂层显微组织、硬度和结合强度的测试,探讨喷涂工艺参数(燃气流量和喷涂距离)的变化对涂层组织与性能的影响。采用扫描电镜(SEM)和能谱仪(EDS)研究涂层的形貌、微观组织及涂层成分,采用显微硬度计和拉伸试验机测试涂层的显微硬度和结合强度。研究结果表明:随着燃气流量的增加,喷涂粉末粒子熔化更充分,涂层中孔隙和氮化硼含量呈降低趋势,涂层硬度增加,结合强度先升高后降低;随喷涂距离增加,氧化物夹杂增多,涂层硬度呈现增大的趋势,结合强度先增加后降低。喷涂距离为225 mm时,涂层孔隙率和氮化硼含量很低,导致其高的硬度和结合强度。

CoCrAlYSi-hBN coating was fabricated using the high-velocity oxygen fuel(HVOF)process under several processing conditions,and the effects of process parameters,gas flow and spray distance,on the microstructure and properties of the coating were investigated in the present paper.The microstructure,hardness,bonding strength and chemical composition of the coating was researched by using scanning electronmicroscopy(SEM),microhardness tester,adhesive strength measuring and energy dispersive spectroscopy(EDS).The results show that with the increasing gas flow,the porosity and h-BN content of the coating are reduced,and the hardness is improved;However,the bonding strength increases first and then decreases due to excessive energy leading serious oxidation.With the increase of spraying distance,the oxide inclusions are increased,which causes the hardness of coatings increase and the bonding strength decrease.In addition,when the spraying distance is 225 mm,the hardness and bonding strength of the coating are the highest due to the low porosity and boron nitride content.