轧辊表面电火花沉积涂层的耐磨性

Wear resistance of WC coating on roller surface prepared by electro-spark deposition

采用电火花沉积工艺,用WC陶瓷硬质合金在铸钢轧辊表面制备了一层合金涂层。采用X射线衍射仪、扫描电镜、显微硬度计等对沉积层的相结构、显微组织、显微硬度及耐磨性能进行了分析。结果表明:沉积层主要由Co3W3C、Fe3W3C、W2C、Si2W等相组成;沉积层与基体呈冶金结合,细小的硬质相弥散分布于沉积层中;沉积层的平均硬度为1915 HV0.3,约是基体硬度(352 HV0.3)的5.4倍;其室温耐磨性能比基体提高了2.1倍,高温耐磨性能比基体提高了1.9倍。室温下沉积层的主要磨损机理为磨粒磨损;高温下沉积层的主要磨损机理为粘着磨损、氧化磨损和疲劳磨损。

WC coatings were prepared on surface of cast steel roller by electro-spark deposition(ESD) technique.The phases,microstructure and microhardness of the coatings were investigated by means of scanning electro microscopy(SEM),X-ray diffraction(XRD) and microhardness test.The results show that the coatings metallurgically bonded with the substrate consist of Fe3W3C,Co3W3C,Si2W and W2C phases.The fine hard phases are distribute a dispersively in the coatings.The average hardness of the coatings(1915 HV0.3) is about 4.4 times higher than that of the substrate(352 HV0.3),its room temperature wear resistance is 2.1 times higher than that of the substrate and its wear resistance at high temperature is 1.9 times higher than that of the substrate.The room temperature wear mechanism is abrasive wear and the wear mechanism at high temperature is combination of adhesive wear,oxidation wear and fatigue wear.