TC4合金表面Ni-SiC-Y_2O_3复合镀层的摩擦磨损性能

Wear Properties of Ni-SiC-Y_2O_3 Composite Coating Prepared on TC4 alloy

为提高TC4合金表面耐磨性能,采用复合镀方法在其表面制备Ni-SiC-Y_2O_3复合镀层,研究镀层的组织结构及其在常温和高温下(600℃)下的摩擦磨损行为。结果表明,所制备的Ni-SiC-Y_2O_3复合镀层组织致密且与基体结合紧密,主要由Ni基体和弥散分布其中的SiC颗粒及微量Y_2O_3混合组成。镀层的硬度明显高于TC4基体合金,且由表向内呈梯度降低趋势。与GCr15对摩时,Ni-SiC-Y_2O_3复合镀层在常温和600℃均具有一定程度的减磨作用,并且耐磨性能明显优于TC4基体合金。镀层在常温下的磨损失重显著低于TC4基体合金,此时其磨损机制可以归结为疲劳磨损和轻微的氧化磨损;随磨损温度升高至600℃,镀层的磨损失重明显增大,此时的磨损机制为严重的氧化磨损、削层磨损和疲劳磨损。

Ni-SiC-Y2O3 composite coatings were prepared on TC4 alloy using composite electroplating technology to improve wear resistance. Micro-structure and wear behavior of the coatings were investigated at room temperature and 600 ℃,respectively. The results show that the obtained Ni-SiC-Y2O3 composite coatings are dense and compact, consisting of Ni matrix with dispersed SiC particles and trace Y2O3 powders. Micro-hardness of the coating is obviously higher than that of TC4 substrate, which also presents a decreasing tendency on the depth direction from the coating surface to the substrate.Sliding against GCr15 ball, the Ni-SiC-Y2O3 composite coating has friction-reduction effect in a certain extent at both room temperature and 600 ℃. Wear resistance of the coating is superior to TC4 alloy at each evaluated conditions. Sliding at the room temperature, the mass loss of the coating after wear is much lower than that of TC4 alloy. The main wear mechanisms of the coating is fatigue wear combined with slight oxidation wear. While sliding at 600 ℃, the mass loss of the coating increases obviously and the main wear mechanisms are considred as serious oxidation wear, delamination abrasion and fatigue wear.