大气等离子和超音速火焰喷涂CoCrAlYSi-hBN涂层组织和性能对比

目的 针对航空发动机叶片榫头/榫槽摩擦副工作中的微动磨损问题,开展CoCrAlYSi-hBN抗微动磨损涂层研究.方法 通过大气等离子(APS)和超音速火焰(HVOF)喷涂工艺,制备CoCrAlYSi-hBN涂层,采用扫描电镜(SEM)研究涂层的形貌和微观组织,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,采用SRV试验机探究涂层的摩擦磨损性能.结果 APS喷涂CoCrAlYSi-hBN涂层熔化更充分,显微组织均匀,具有更多高含量的hBN和孔隙;HVOF喷涂CoCrAlYSi-hBN涂层显微组织具有明显的层状结构,涂层致密,hBN和孔隙含量少;APS喷涂CoCrAlYSi-hBN涂层的硬度平均值为168.4HV0.3,结合强度平均值为44.6 MPa,远小于HVOF喷涂CoCrAlYSi-hBN涂层的硬度(327.1HV0.3)和结合强度平均值(59.5 MPa).相比HVOF喷涂CoCrAlYSi-hBN涂层,APS喷涂CoCrAlYSi-hBN涂层虽然有更低的摩擦系数(0.75),但涂层磨损更严重,涂层磨痕表面有明显的涂层剥落,HVOF喷涂CoCrAlYSi-hBN涂层磨痕则出现更多的犁沟.结论 HVOF喷涂工艺制备的CoCrAlYSi-hBN涂层的综合性能优于APS喷涂CoCrAlYSi-hBN涂层,在摩擦过程中,两种工艺制备的CoCrAlYSi-hBN涂层都会转移到对偶件上,从而减少对偶件的磨损,有作为叶片榫头抗微动磨损涂层的潜力.

Comparison of the Microstructure and Properties of CoCrAlYSi-hBN Coatings Prepared by APS and HVOF Process

To eliminate the fretting wear in a dovetail attachment of a compress blade to a disc, CoCrAlYSi-hBN coatings are fabricated by the atmosphere plasma spray (APS) and high-velocity oxygen fuel (HVOF) spraying process. The microstructure, hardness, bonding strength and wear property are studyed by using scanning electron microscopy (SEM), microhardness tester, adhesive strength measuring and SRV fretting friction wear tester. The coating prepared by APS had a uniformal microstructure with higher content of hBN and pore. However, the coatings prepared by HVOF have a lamellar and dense microstructure with low content of hBN and pore. The hardness and bonding strength of coating prepared by APS is lower than that of coating prepared by HVOF. Although the friction coefficients of coating fabricated by APS is lower than that of coating prepared by HVOF, the coatings prepared by HVOF present a better wear resistance than that prepared by APS. The worn surface of CoCrAlYSi-hBN coatings prepared by APS shows apparent spalling and a little indentation. While the worn surface CoCrAlYSi-hBN coatings prepared by HVOF shows apparent spalling. CoCrAlYSi-hBN coatings have the potential to be used on compressor blades.