TC4钛合金表面微弧氧化原位生长自润滑MoS2/TiO2膜层研究

Study on the self-lubricating MoS2-TiO2 coating on TC4 surface by micro-arc oxidation

摘要:

钛合金表面减摩涂层的设计和制备是提升钛合金构件耐磨性能、保障服役安全的重要技术之一。针对于目前钛合金减摩涂层中减摩剂分散不均匀，易于团聚导致膜基结合力差等问题，本论文采用一步微弧氧化技术在TC4合金表面原位生长纳米MoS2颗粒，制备具有减磨作用的MoS2/TiO2复合陶瓷膜层；讨论了原位反应中硫源添加量对膜层微观结构及耐磨性能的影响。结果表明：以Na2S和Na2MoO4分别为硫源和钼源在TC4合金表面通过微弧氧化制备出了MoS2/TiO2复合陶瓷膜层；通过控制Na2S浓度可以原位生成具有小尺寸、均匀化分布的纳米MoS2颗粒，并实现对MoS2含量和形态的调控。随着Na2S浓度的增加，膜层结构逐渐致密化且表面粗糙度较低，当添加量到达60g/L时，由于硫沉淀作用导致膜层开始疏松，粗糙度增加。由于膜层表面和内部均存在均匀化分布且具有自润滑作用的MoS2颗粒，所得膜层耐磨性较传统微弧氧化膜层或直接添加MoS2颗粒所得膜层分别提高了395.4%、129.4%；同时，膜基结合力较传统微弧氧化提高了87.1%，达到了723.8N，说明了该技术在保证良好的自润滑效果同时改善了膜基结合力。该研究结果可以为钛合金耐磨涂层设计和制备提供新思路和研究方法。

Abstract:

The design and preparation of antifriction coating on titanium alloy surface is one of the important technologies to improve the wear resistance of titanium alloy components and ensure the safety in service. In order to solve the problems of uneven dispersion of antifriction agents and poor adhesion of coating caused by easy agglomeration in titanium alloy antifriction coating, this paper adopts one-step micro-arc oxidation technology to generate MoS2/TiO2 composite ceramic coating with anti-wear effect on the surface of titanium alloy in situ. The effects of sulfur source concentration on microstructure and wear resistance of the coating was discussed. The results showed that MoS2/TiO2 composite ceramic film was successfully prepared by micro-arc oxidation with Na2S and Na2MoO4 as sulfur source and molybdenum source respectively. By controlling Na2S concentration, nano-MoS2 particles with small size and uniform distribution can be generated in situ, and the content and morphology of MoS2 can be regulated. With the increase of Na2S concentration, the coating becomes compact and the roughness decrease. When the addition amount reached 60g/L, the coating turn into loose due to sulfur precipitation and the roughness increased. Due to the uniform distribution of MoS2 particles on the surface and inside of the coating, the abrasion resistance of the obtained coating improved by 395.4% and 129.4% respectively compared with the conventional micro-arc oxidation coating or the coating prepared by directly adding MoS2 particles into the electrolyte. At the same time, adhesion (reaching 723.8N) increased by 87.1% compared with traditional micro-arc oxidation, indicating that this technology not only guarantees good self-lubrication effect, but also improves adhesion of coating and matrix. The results can provide new ideas and research methods for the design and preparation of titanium alloy wear-resistant coatings.