送粉激光熔覆合成制备WC/Ni硬质合金涂层及其耐磨性

WC/Ni Cemented Carbide Coating and Its Wear Resistance Synthesized by Laser Powder Feeding Cladding

借助同轴送粉法将W/C/Ni元素混合粉末送入熔池,利用激光熔池中热力学和动力学条件,在优化材料成分和激光熔覆工艺参数条件下可以直接反应合成出WC颗粒,形成以WC/Ni为主的复合涂层.熔覆层中含有WC,CW3,α-W2C,W2C,Fe6W6C,FeW3C,W3O,C等相.添加2wt%的Cr3C2可以细化涂层中的WC颗粒尺寸,颗粒平均尺寸为4～6μm,硬度值为85HRA左右.激光合成制备的WC/Ni硬质合金涂层的耐磨性尚不及YG8硬质合金的耐磨性,但比渗氮处理试块的耐磨性提高了7.9倍.激光直接合成硬质合金涂层的成本低,可在零件的任何部位原位合成,形状尺寸不受限制.

This paper presented the research results on laser synthesizing WC/Ni cemented carbide coating by coaxial feeding its formation elements into the molten pool based on the unique physical and chemical metallurgy within the molten pool. WC particles can be synthesized by reaction under optimization of composition and processing parameters. The coating contains WC ,CW3 ,α-W2C ,W2C,Fe6W6C,FeW3C,W3O and C phases. The size of WC particle can be reduced to 4～6μm by adding 2wt% Cr3C2. The hardness of the coating reaches 85HRA. The ring and block wear test results show that the wear resistance of the laser synthesized WC/Ni cemented carbide coatings is lower than that of the sintered YG8 hard alloy ,but is 7.9 times higher than that of the nitrided steels. Laser direct synthesizing cemented carbide coating by pure element mixture is relatively low cost, without limitation on size and location.