TC4合金表面Zr-Y改性渗硅涂层的组织结构及高温摩擦磨损性能

Microstructure and high-temperature wear performance of Zr-Y modified silicide coating deposited on TC4 alloy

采用固体粉末扩散渗方法在TC4合金表面制备了Zr-Y改性的渗硅涂层,研究了渗层的组织结构、高温摩擦磨损性能及磨损机制。结果表明:Zr-Y改性渗硅涂层具有多层梯度结构,外层由TiSi_(2)和少量ZrSi_(2)组成,较薄的中间层为TiSi相,内层为Ti_(5)Si_(4)和Ti_(5)Si_(3)的混合物。涂层的显微硬度明显高于TC4合金基体,且由表及内呈梯度降低趋势。高温摩擦磨损实验(600℃)结果表明,Zr-Y改性渗硅涂层具有优良的摩擦磨损防护性能。与GCr15对磨时的磨损率约为3.59×10^(-5)mm^(3)/(N·m),是相同条件下TC4合金磨损率的36.6%,磨损机制主要为GCr15在涂层表面的擦涂和氧化磨损。与Al2O3球对磨时的磨损率为9.75×10^(-5)mm^(3)/(N·m),是相同条件下TC4合金磨损率的18.9%,磨损机制为疲劳磨损、氧化磨损和黏着磨损。

Zr-Y modified silicide coating was deposited on TC4 alloy by the pack cementation process.The microstructure,friction and wear performance,and wear mechanisms of the coating were investigated.The results show that the Zr-Y modified silicide coating has a multi-layer structure,an outer layer consists of TiSi_(2)and a small amount of ZrSi_(2),a thin middle layer is TiSi,and an inner layer is a mixture of Ti_(5)Si_(4)and Ti_(5)Si_(3).The micro-hardness of the coating is much higher than that of the TC4 substrate and exhibits an obvious decrease tendency from the surface to the interior.The Zr-Y modified silicide coating possesses good anti-wear performance when wearing against GCr15 and Al2O3 balls at a high-temperature of 600℃.When wearing against GCr15,the wear rate of the coating is about 3.59×10^(-5)mm^(3)/(N·m),which is about 36.6%of that of the TC4 substrate,and the main wear mechanisms are characterized by the adhesive of GCr15 on the coating surface and oxidation wear.When wearing against the Al2O3 ball,the wear rate of the coating is about 9.75×10^(-5)mm^(3)/(N·m),which is about 18.9%of that of the TC4 substrate,and the wear mechanisms are fatigue wear,oxidation wear,and adhesion wear.