钛合金表面激光熔覆高温自润滑耐磨复合涂层  

High temperature self-lubrication anti-wear composite coatings on titanium alloy by laser cladding

作　　者：孟祥军[1,2] 刘秀波[1,3] 刘海青[1] 陈瑶[1] 

机构地区：[1]苏州大学机电工程学院,苏州215006 [2]江苏城乡建设职业学院,常州213147 [3]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

出　　处：《焊接学报》2015年第5期59-64,116,共7页Transactions of The China Welding Institution

基　　金：江苏省自然科学基金资助(BK20141194;BK20131155);江苏省材料摩擦学重点实验室开放基金(Kjsmcx201301)

摘　　要：为了提高钛合金的摩擦学性能,采用激光熔覆技术在Ti-6Al-4V合金表面制备了γ-Ni Cr Al Ti/Ti C与γ-NiCr Al Ti/Ti C/Ca F2复合涂层.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)分析了涂层的物相和显微组织,在球-盘式高温摩擦磨损试验机上测试了不同温度下(室温,300℃,600℃)复合涂层的摩擦学性能.结果表明,激光熔覆的复合涂层与基体呈冶金结合,γ-Ni Cr Al Ti/Ti C/Ca F2复合涂层主要由"原位"生成的小块状,针状Ti C颗粒及Ti C树枝晶,γ-Ni Cr Al Ti固溶体基体及弥散分布的球状Ca F2颗粒组成.由于硬质增强相Ti C与增韧相γ-Ni Cr Al Ti的共同作用,γ-Ni Cr Al Ti/Ti C与γ-Ni Cr Al Ti/Ti C/Ca F2复合涂层的磨损率在试验温度下都远低于Ti-6Al-4V基体;在600℃时,γ-Ni Cr Al Ti/Ti C/Ca F2涂层的平均摩擦系数为0.21,相对于基体与γ-Ni Cr Al Ti/Ti C涂层分别降低了43%,50%,表现出良好的高温自润滑减摩性能.To improve the tribological property of titanium alloy,γ-NiCrAlTi/TiC composite coatings and γ-NiCrAlTi/TiC/CaF 2high-temperature self-lubrication composite coatings were fabricated on Ti-6Al-4V alloy by laser cladding technology. The constituents and microstructure of the fabricated coatings were examined by X-ray diffraction( XRD),scanning electron microscope( SEM),energy dispersive spectroscopy( EDS) techniques,and the tribological properties were evaluated using a ball-on-disc tribometer under dry sliding wear test conditions at room-temperature,300 ℃,600 ℃,respectively. The results show that the bonding of the coatings to the substrates is completely metallurgical. The microstructure of the γ-NiCrAlTi/TiC /CaF2 cladding coating is consisted of the 'in-situ'synthesized small clump and needle shaped TiC particles,TiC dendrite,γ-NiCrAlTi solid solution and spherical CaF 2particles. The wear rate of the fabricated coatings was greatly decreased mainly due to the combined effect of the wear-resistant TiC carbides and the ductile γ-NiC rA lT i matrix. Moreover,the average friction coefficient of γ-NiCrAlTi/TiC/CaF2coating was 0. 21 at 600 ℃,which was reduced by 43 % and 50 % compared to the substrate and γ-NiCrAlTi/TiC coating,respectively. It indicates that γ-NiCrAlTi/TiC/CaF2 coating has good friction-reducing and antiwear properties at high temperature.

关 键 词：激光熔覆 固体润滑 高温耐磨复合涂层 显微组织 性能 

分 类 号：TG174.4[金属学及工艺—金属表面处理]