超音速火焰喷涂WC-12Co涂层的高温摩擦磨损性能

High Temperature Friction and Wear Properties of WC-12Co-4Cr Sprayed by HVOF

WC-Co-Cr是一类具有高硬度、耐磨损、耐腐蚀的金属陶瓷复合涂层材料,常用于工业生产中苛刻服役环境的工件表面防护。本试验采用超音速火焰喷涂(HVOF)技术在Q235钢表面分别制备了WC-12Co-4Cr和WC-12Co复合涂层。使用XRD、光学显微镜、SEM以及附带的EDS、显微硬度计分别对比研究了两组涂层的物相、微观形貌、元素分布、显微硬度和孔隙率。采用球盘式摩擦试验机重点研究两组涂层在常温(25℃)、300℃、600℃下的摩擦磨损性能。实验结果表明,加入Cr元素的WC-12Co-4Cr复合涂层的硬度为1050 HV_(0.5)比WC-12Co涂层的995 HV_(0.5)更高。常温和300℃下两组涂层的抗摩擦磨损性能基本相似,其中常温下WC-12Co-4Cr复合涂层的摩擦系数和磨损率分别为0.4、2.61×10^(-17) m^(3) (N·m)^(-1),磨损机制为磨粒磨损。而在高温(600℃)条件下磨损机制转变为粘着磨损且抗磨损性能显著优于WC-12Co涂层;摩擦系数为0.62、磨损率为1.1×10^(-15) m^(3)(N·m)^(-1),相同条件下的WC-12Co涂层磨损率为7.2×10^(-15) m^(3) (N·m)^(-1)。

WC-Co-Cr is a kind of cermet composite coating material with high hardness,wear resistance and corrosion resistance,which often used in workpiece surface protection with harsh service environment in industrial production.In this experiment,WC-12Co-4Cr and WC-12Co composite coatings were prepared on the surface of Q235 steel by high velocity oxygen fuel(HVOF)technology.The phase,microstructure,element distribution,microhardness and porosity of coatings were tested by XRD,optical microscope,SEM,EDS and microhardness tester.The friction and wear properties of coatings at room temperature(25℃),300℃and 600℃were studied using the ball-disc friction testing machine.The test results showed that the hardness of WC-12Co-4Cr coating with Cr element was higher than WC-12Co coating,which was 1050 HV_(0.5).The friction and wear resistance of coatings at room temperature and 300℃were basically similar.The friction coefficient and wear rate of the WC-12Co-4Cr coating at 25℃were 0.4 and 2.61×10^(-17) m^(3)(N·m)^(-1),respectively.The wear mechanism was abrasive wear.At high temperature(600℃),the wear mechanism changes to adhesive wear and the wear resistance of WC-12Co coating was significantly better than WC-12Co coating.The friction coefficient was 0.62,and the wear rate was 1.1×10^(-15)m^(3)(N·m)^(-1).While,under the same conditions,the wear rate of WC-12Co coating was7.2×10^(-15)m^(3)(N·m)^(-1).