Study On The Dry Sliding Friction Wear Performance Of Vacuum Brazing NiCrBSi/WC-10Ni Composite Coating

In this paper,WC-10Ni/NiCrBSi composite coating was prepared on the surface of Q235A steel by using flexible coating fabric technology and vacuum brazing technology.The wear resistance and wear mechanism of each layer in the composite coating and the effect of parameters for coating preparation and Friction test parameters on the dry sliding friction wear performance and Wear mechanism of composite coating were studied by using HT-1000 friction and wear tester,scanning electron microscope,laser scanning confocal microscope and other equipment.WC-10Ni/NiCrBSi composite coating prepared by"metal cloth"with WC-10Ni mass fraction of 80%at 1060°C brazing temperature is divided into surface layer and hard layer.The surface layer mainly contains?-Ni and Cr3Ni2Si,and the average hardness is694HV_0.2,the hard layer mainly contains?-Ni,WC,Cr₂₃C₆ and Ni₃Si,and the average hardness value reaches 963HV_0.2.When the load is 20N,the rotation speed is 400r/min,the wear radius is 5mm,the wear time is 1 hour,and the grinding material is 5mm Si3N4ceramic ball.The wear rate of the hard layer is only 14.8%of that of the substrate and27.8%of the surface layer.The wear mechanism of the surface layer is mainly adhesive wear and a certain abrasive wear.The wear mechanism of the hard layer is mainly abrasive wear accompanied by slight adhesive wear.When the mass fraction of WC-10Ni is 50%,the hardness of the hard layer increases slightly,the wear rate and friction coefficient decrease,and the wear mechanism does not change with the increase of brazing temperature.When the brazing temperature is unchanged at 1060°C,as the mass fraction of WC-10Ni increases,the area fraction of WC particles in the hard layer becomes larger,the Rockwell hardness of the hard layer increases,and the wear rate decreases significantly.The wearability is significantly improved and the wear mechanism changes.When the mass fraction is less than 30%,the wear mechanism is mainly adhesive wear with a small amount of abrasive wear;When the mass fraction is40%⁶0%,the wear mechanism is mainly fatigue wear and oxidative wear with a small amount of abrasive wear;when the mass fraction is 70%⁸0%,the wear mechanism is dominated by abrasive wear with a small amount of adhesive wear.The wear rate of WC-10Ni/NiCrBSi composite coating prepared by"metal cloth" with WC-10Ni mass fraction of 50%at 1060°C brazing temperature varies with the test temperature,and is largest at 200°C and the smallest at 400°C.When the test temperature is 100°C,the wear mechanism is the combination of fatigue wear and oxidative wear;when the test temperature reaches 200°C,the wear mechanism is mainly the combination of adhesive wear and oxidative wear;when the test temperature reaches300°C⁵00°C,The wear mechanism is transformed into a combination of abrasive wear and oxidative wear.In addition,with the increase of load,the wear rate of the composite coating increases remarkably,and the wear mechanism changes.When the load is 5N and10N,the wear mechanism is mainly abrasive wear;When the load is 15N,the wear mechanism is mainly fatigue wear accompanied by a small amount of abrasive wear and oxidative wear;The wear mechanism is mainly fatigue wear and oxidative wear with a small amount of abrasive wear when the load is 20N.