超音速火焰喷涂WC-10Co4Cr涂层的耐滑动磨损行为

采用超音速火焰喷涂(HVOF)工艺制备微米结构WC-10Co4Cr涂层,分别采用金相显微镜、扫描电镜(SEM)、X射线衍射(XRD)和滑动磨损设备分析涂层的微观结构和滑动磨损行为。结果表明:采用液体煤油燃料HVOF喷涂的微米结构WC-10Co4Cr涂层的脱碳程度较低,涂层中仅出现WC和W2C相,而无η相(Co3W3C、Co6W6C)以及软相W。涂层微观结构致密,孔隙率约为1%,平均显微硬度为1 322HV0.3;在相同试验条件下,WC-10Co4Cr涂层的摩擦因数(约0.8)高于不锈钢(1Cr18Ni9Ti)的摩擦因数(约0.5),其滑动体积损失量仅为不锈钢涂层的1/146,具有优异的抗滑动磨损性能。涂层在滑动磨损过程中首先是粘结相的脱落,然后是WC颗粒的磨损。

Sliding wear behavior of high-velocity oxy-fuel sprayed WC-10Co4Cr coatings

The micro-structured WC-10Co4Cr coatings were deposited by the high-velocity oxy-fuel(HVOF) spray process.The microstructure and sliding wear behavior of the coatings were respectively characterized by optical microscopy,scanning electron microscopy(SEM),X-ray diffraction(XRD) and sliding wear test.The results show that decarborization of the coating is low by using liquid kerosene as fuel.Only WC and W2C exist in the sprayed coating,while there is no η phase(Co3W3C,Co6W6C) or the soft phase W.The coating is highly densified with porosity as low as about 1% and the microhardness of the coating is 1 322 HV0.3.The coefficient of friction for WC-10Co4Cr coating(about 0.8) is higher than that for 1Cr18Ni9Ti stainless steel(about 0.5) and the volume loss of sliding wear is only 1/146 of that of 1Cr18Ni9Ti,indicating the excellent sliding wear resistance performance of the WC-10Co4Cr coating.The failure of the WC-10Co4Cr coating during sliding wear is due to binder phase loss followed by wearing of WC particles.