不同保温时间对AT13涂层摩擦学性能的影响

Effect of Different Holding Time on Tribological Properties of AT13 Coating

采用等离子喷涂技术在20钢表面制备Al_2O_3-Ti O_2涂层,对所制备的涂层进行500℃保温1 h、3 h、5 h热处理。利用QG-700型摩擦磨损试验机对涂层进行摩擦磨损性能试验。利用显微硬度计、扫描电镜(SEM)和X射线衍射仪(XRD)对涂层的组织性能、力学性能及摩擦磨损性能进行表征。研究结果表明:原始粉末中主要为Al_2O_3和Al_2Ti O_5相,喷涂后生成Ti O新相。热处理后涂层无新相生成,显微硬度有所降低,摩擦因数有所提高,达到稳定磨损阶段的时间缩短,涂层的磨痕宽度较未热处理时变窄、变浅。热处理降低了涂层的磨损率,随着保温时间的延长,磨损率降低幅度减小。热处理前后涂层均存在磨屑和剥落坑,主要磨损机制为剥落。在本试验条件下,保温时间为5 h时,涂层的耐磨性最好。

Plasma spraying technology was utilized to deposit Al2 O3-Ti O2 coatings on 20 steel samples. The prepared coating was heat-treated at 500 ℃ for 1 h,3 h and 5 h. The friction and wear performance of coatings were tested by QG-700 friction and wear tester. The microstructures,microhardness and phase compositions of the coatings were investigated by scanning electron microscopy,microhardness tester and X-ray diffraction,respectively. The results indicate that the original powders are mainly Al2 O3 and Al2 Ti O5 phases. Ti O is a new phase formed after spraying. The heat treatment does not change the phase composition of the coating. After heat treatment the microhardness of the coating decreases and the friction factor increases. The time for the coating to reach a stable wear stage after heat treatment is shortened. The wear marks of the coatings after heat treatment become lighter than those of the non-heat treated coatings. Heat treatment can reduce the wear rate of the coatings. The untreated and heat-treated coatings have wear debris and exfoliation pits. The main wear mechanism of the coating is exfoliation. Under the experimental conditions,the wear resistance of the coating is the best when the holding time is 5 h.