不同粘结剂成分WC-30%(Co-Ni-Cr)粗晶硬质合金高温氧化行为的研究

High-Temperature Oxidation Behavior of Coarse-Grained WC-30%(Co-Ni-Cr)Cemented Carbides with Different Binder Components

本文以WC、Co、Ni粉为主要原料,采用传统粉末冶金方法制备了3种不同粘结剂成分的WC-30%(Co-Ni-Cr)粗晶硬质合金样品,采用金相显微观察、特征X射线能谱分析、扫描电镜和X射线衍射分析手段,研究了在900℃氧化时WC-30%(Co-Ni-Cr)硬质合金的高温氧化行为。研究结果表明:WC-30%Co合金氧化增重为0.019 g/cm^(2),单位面积氧化增重高于WC-20%Co-9%Ni-1%Cr和WC-14.5%Co-14.5%Ni-1%Cr合金,WC-30%Co合金的抗氧化性能最差;WC-30%(Co-Ni-Cr)合金随着粘结剂中Ni含量的增加,抗氧化性能增强;WC-30%(Co-Ni-Cr)合金样品氧化层表面均形成了MWO_(4)(M=Co、Ni)的氧化产物,在氧化中间层形成了WO_(3)、MWO_(4)(M=Co,Ni)、MO(M=Co,Ni)的氧化产物,且在WC-14.5%Co-14.5%Ni-1%Cr合金中发现更明显的MO(M=Co,Ni)衍射峰。

In this paper,coarse-grained WC-30%(Co-Ni-Cr)cemented carbides with three different binder components were prepared by traditional powder metallurgy with WC,Co,and Ni powder as the main raw materials.Moreover,metallographic microscopic observation,characteristic energy dispersive X-ray spectroscopy(EDS),scanning electron microscopy(SEM),and X-ray diffraction(XRD)were used to study the high-temperature oxidation behavior of WC-30%(CoNi-Cr)cemented carbides at 900℃.The results reveal that the oxidation mass gain of the WC-30%Co cemented carbide is 0.019 g/cm^(2),with the oxidation mass gain per unit area higher than that of the WC-20%Co-9%Ni-1%Cr and WC-14.5%Co-14.5%Ni-1%Cr cemented carbide,and the WC-30%Co cemented carbide exhibits the worst oxidation resistance.The oxidation resistance of the WC-30%(Co-Ni-Cr)cemented carbide increases with the increase in Ni content in binders.On the surface of the oxidation layer of the WC-30%(Co-Ni-Cr)cemented carbide,the oxidation product of MWO_(4)(M=Co,Ni)is formed,and WO_(3),MWO_(4)(M=Co,Ni),and MO(M=Co,Ni)are formed in the intermediate oxidation layer.The more prominent diffraction peak of MO(M=Co,Ni)is found in the WC-14.5%Co-14.5%Ni-1%Cr cemented carbide.