接触应力和相对滑动速度对金属表面自修复膜生成的影响及机制

采用羟基硅酸镁粉体作为润滑油添加剂,在MMU-5G材料端面摩擦磨损试验机上,研究了不同接触应力和相对滑动速度对45^#钢/45^#钢摩擦副磨损表面自修复膜生成的影响及其机制,借助SEM及EDS测试分析摩擦副的表面形貌及表面成分组成。结果表明,接触应力和相对滑动速度对羟基硅酸镁粉体添加剂在磨损表面形成自修复膜影响显著。在接触应力为1.53,3.06,4.59,7.64MPa和在相对滑动速度0.416m/s的工况条件下,试样磨损表面有自修复膜生成。接触应力为3.06MPa和相对滑动速度为0.416m/s时,易于在短时间内达到磨损-自修复动态平衡,自修复效果最为理想。自修复膜的生成过程包含磨粒磨损和摩擦化学反应2个阶段。自修复膜的生成使得试样摩擦磨损表面平整光滑,可以有效降低金属磨损。

Influence and Mechanism of the Formation of Self-repair Coatings on Metal Surface under Different Contact Stress and Relative Sliding Speed

Influence and mechanism of self-repair coating on the worn surfaces of 45 steel pairs were investigated by using MMU-5G end-face friction and wear tester under lubricated condition with different contact stress and relative sliding speed. The surface images of self-repair coatings and their chemical composition were detected by using SEM and EDS. The experimental results show varying contact stress and relative sliding speed have a great influence on the formation of self- repair coating on the worn surface. Self-repair coatings are formed with the contact stress of 1.53,3. 06,4. 59 and 7.64 MPa and with the sliding speed of 0. 416 m/s. The dynamical equilibrium of wear and self-repair can be achieved in a short time with the contact stress of 3.06 MPa and with the sliding speed of 0. 416 m/s,while the self-repair coatings with high quality are formed. The formation of self-repair coatings consists of two stages of abrasive wear and tribochemical reaction. The surface of 45 steel with self-repair coatings is flat and smooth which can improve the wear resistance of the metals.