复合稀土氧化物对Ti-Al/WC涂层组织和摩擦学性能的影响

Effect of composite rare earth oxides on microstructure and tribological properties of Ti-Al/WC coating

采用等离子喷涂方法制备了未添加稀土氧化物以及含有不同复合稀土氧化物的Ti-Al/WC涂层,使用自带能谱仪的扫描电镜、X射线粉末衍射仪和电子天平对各类涂层的磨损表面及截面组织形貌、残余应力和磨损量进行了观察和检测,使用摩擦磨损试验机比较和分析了不同类型涂层的耐磨性能。结果表明:含有稀土氧化物的Ti-Al/WC涂层内部晶粒得到细化,颗粒物含量大幅度减少,孔洞变小,裂纹数量及尺寸显著降低。与只含一种稀土氧化物的涂层相比,复合稀土氧化物对涂层微观组织改善情况更加明显。当同时加入CeO2、Y2O3和La2O3后,涂层组织中的显微缺陷最少,各成分分布最为均匀,截面显微形貌最好,此时,涂层的残余应力达到最小值275.7 MPa,且耐磨性最强,总磨损量仅有16.8 mg。与未添加稀土氧化物的涂层相比,二者分别减少了30.3%和69.8%。

Ti-Al/WC coatings of rare earth oxide-free and containing different composite rare earth oxides were prepared by plasma spraying.The worn surface,cross section microstructure,residual stress and wear mass loss of the coatings were observed and detected by using scanning electron microscopy with energy spectrometer,X-ray powder diffractometer and electronic balance.The wear resistance of the coatings was compared and analyzed by using friction and wear tester.The results show that the internal grains of the Ti-Al/WC coating containing rare earth oxide are refined,particulates are greatly reduced,holes are smaller and the number and size of cracks are significantly reduced.Compared with the coating containing only a kind of rare earth oxide,the composite rare earth oxides are more effective in improving microstructure of the coating.When Ce O2,Y2O3 and La2O3 are all added into the coatings,the defects in microstructure are the least,the components are most evenly distributed,and the cross section morphologies are the best.At the same time,the residual stress of the coating reaches a minimum of 275.7 MPa,the wear resistance is the strongest and the total wear mass loss is only 16.8 mg,compared with the coating of rare earth oxide-free,they are reduced by 30.3% and 69.8% respectively.