第二相增强铁基非晶复合涂层耐磨性能研究

Wear Resistance of the Second Phase Reinforced Ferro-based Amorphous Composite Coating

目的改善涂层的耐磨性能。方法挑选球状碳化钨粉末、块状金属钨粉、类球形氧化铝粉末、片状氧化铝粉末、氮化硅晶须、片状硫化钼粉末以及块状氮化钛粉末作为增强相,制备出铁基非晶复合涂层,分析涂层的组织与显微结构,表征非晶相与第二相之间的界面结合,并对不同涂层的耐磨性能进行测试,讨论第二相性质对复合涂层性能产生的影响。结果涂层的摩擦因数主要与表面氧化程度有关,低负载下W、WC以及球状Al_(2)O_(3)颗粒相能够减少涂层表面非晶的晶化,摩擦因数均低于0.3;高负载下非晶涂层的摩擦因数主要受涂层表面硬质相上粉率的影响,提高硬质相的上粉率能有效改善涂层的耐磨性能,上粉率较高的W、球状Al_(2)O_(3)以及WC 3种涂层最终的摩擦因数分别为0.41、0.44以及0.45,其余硬质相占比较低的涂层均在0.48左右。结论涂层磨损主要分为3个阶段:初期的磨合阶段、中期的稳定磨损阶段,以及涂层由于摩擦过程的热量积累出现氧化,当氧化积累到一定程度后就进入后期的剧烈磨损阶段,涂层表面的氧化脱落与新相生成的速度达到平衡,摩擦因数逐渐稳定不再变化。

The work aims to improve the wear resistance of coating.Spherical tungsten carbide powder,massive metal tungsten powder,spheroidal alumina powder,flake alumina powder,silicon nitride whisker,flake molybdenum sulfide powder and massive titanium nitride powder were selected as the reinforcement phase to prepare iron based amorphous composite coating.The structure and microstructure of the coating were analyzed,the interface bonding between the amorphous phase and the second phase was characterized,and the wear resistance of different coatings was tested.The effect of the second phase properties on the performance of composite coating was discussed.The friction coefficient of the coating was mainly related to the degree of surface oxidation.W,WC and spherical Al_(2)O_(3) particle phase could reduce the crystallization of the amorphous surface of the coating under low load,and the friction coefficient was lower than 0.3.The friction coefficient of the amorphous coating under high load was mainly affected by the powder ratio of the hard phase on the surface of the coating.Increasing the powder ratio of the hard phase could effectively improve the wear resistance of the coating.The final friction coefficients of the three coatings with the highest powder ratio of W,spherical Al_(2)O_(3) and WC were 0.41,0.44 and 0.45,respectively.The friction coefficients of the remaining coatings with relatively low hard phase ratio were about 0.48.Coating wear is mainly divided into three stages:the initial running-in stage,the intermediate stable wear stage and the stage in which the coating oxidizes due to the heat accumulation during the friction process.When the oxidation accumulates to a certain extent,the coating enters the later intense wear stage.The oxidation shedding of the coating surface is in balance with the speed of new phase formation,and the friction coefficient is gradually stable,without change.