W粉含量对发动机Ti5111合金表面MAO涂层组织和摩擦性能的影响

Effect of W Powder Content on Microstructure and Friction Performance of MAO Coating on Ti5111 Alloy Surface of the Engine

为了提高发动机Ti5111合金表面微弧氧化涂层的摩擦性能,利用共生沉积工艺并通过高温作用使W粉扩散到MAO涂层内,通过实验测试的手段观察W粉含量对其组织和摩擦性能的影响。研究结果表明:MAO涂层先发生厚度和表面粗糙度线性增加,之后达到一个较为平缓阶段。加入少量的W粉后,出现了熔融烧结,在涂层上颗粒数量也发生了降低。当加入W粉含量为6 g/L时得到了许多较小的微孔,微孔个数发生降低。不加W粉下,在MAO涂层内主要存在锐钛矿、金红石、氧化钛。逐渐提高W粉量后,W相形成的衍射峰强度升高。加入少量的W粉时,相对基体试样都发生了摩擦系数降低。W粉含量为6 g/L时,摩擦系数相比原始MAO涂层降低了14%左右。未加入W粉时制得的MAO涂层出现了机械啮合,发生了明显的塑性变形;添加少量W粉时发生了大量W粉脱落的情况,达到了更高磨损率并产生了明显犁沟效应。

In order to improve the tribological performance of the micro-arc oxidation coating on the surface of Ti5111 alloy engine, the co-existing deposition process was used and the W powder was diffused into the MAO coating by the action of high temperature.The results show that the thickness and surface roughness of MAO coating first increase linearly and then reach a relatively flat stage.After a small amount of W powder is added, melting and sintering occur, and the number of particles on the coating also decreases.When W powder content is 6 g/L,many small pores are obtained, and the number of pores decreases.Without W powder, there are mainly anatase, rutile, and titanium oxide in MAO coating.With the increase of W powder, the diffraction peak intensity of the W phase increases.When a small amount of W powder is added, the friction coefficient decreases relative to the matrix sample.When W powder content is 6 g/L,the friction coefficient is about 14% lower than that of the original MAO coating.The MAO coating produced without W powder appears mechanical engagement and has obvious plastic deformation.When a small amount of W powder is added, a large amount of W powder falls off, which results in a higher wear rate and an obvious furrow effect.