超音速火焰喷涂WC-Co涂层耐磨性研究

利用超音速火焰喷涂（HVOF）工艺制备了WC-Co涂层，测定了涂层孔隙率、显微硬度及干摩擦磨损过程中涂层材料失重，得出涂层干摩擦因数随时间的变化关系，分析了涂层摩擦磨损机制。结果表明，WC-Co涂层致密，平均孔隙率为1．29％，显微硬度达1140HV（测试载荷2．94N），干摩擦条件下材料失重低于电镀Cr镀层2个数量级；摩擦初期，干摩擦因数迅速增加，主要磨损特征是粘结相富Co区的犁沟切削，摩擦中后期，摩擦副间实际接触面积增大，摩擦因数变化较小，磨损趋于稳定。WC-Co涂层的主要磨损机制是疲劳磨损和犁沟切削。

Study on Wear Resistance of WC-Co Coatings Sprayed by High Velocity Oxy-fuel Spraying

WC-Co coating were prepared on 45 steel substrate by means of high velocity oxy-fuel spraying(HVOF).Coating porosity,micro-hardness and loss of coating in the dry sliding friction test were studied.Profile of the dry sliding friction coefficient was described and the wear mechanisms of the WC-Co coatings were discussed.The results show that the WC-Co coating is compact with the porosity of 1.29 percent.The hardness of coating is 1 140HV under the press of 2.94 N.The loss of WC-Co coating under the dry sliding friction is less than that of electroplate chromium coating by two digital grades.The dry sliding friction coefficient increases rapidly and abrasion wear behavior of WC-Co coating presents the characteristics of micro-cutting of cobalt in the first course of the dry friction test.However,in the following stage the dry sliding friction coefficient changes less and abrasion wear is stable because the contact area between the friction materials is increased.The main abrasion modes of WC-Co coatings are the fatigue desquamation and the micro-cutting.