镍、铬对硬质合金酸性盐雾腐蚀性能的影响

Effect of Nickel and Chromium Additions on Acid Salt Spray Corrosion Properties of Cemented Carbide

本文采用传统粉末冶金工艺制备了WC-8%Co、WC-6%Co-2%Ni-0.4%Cr3C2、WC-8%Ni-0.4%Cr3C2硬质合金样品,利用酸性盐雾试验、极化曲线测试、扫描电镜观察和能谱分析等手段,研究了添加Ni、Cr等元素对硬质合金酸性盐雾环境中腐蚀行为的影响.试验结果表明:WC-Co硬质合金在酸性盐雾环境下由于粘结相标准还原电极电位低,更容易发生电化学腐蚀,造成粘结相流失;添加Ni和Cr,可以提高WC-Co硬质合金的电极电位,降低极化电流密度,提高其在酸性盐雾溶液中的抗腐蚀能力;扫描电镜和能谱分析结果表明添加Ni和Cr,可以降低硬质合金在酸性盐雾溶液中粘结相的流失.

In this paper,WC-8%Co,WC-6%Co-2%Ni-0.4%Cr3C2 and WC-8%Ni-0.4%Cr3C2 cemented carbide samples were prepared by traditional powder metallurgy method.The effects of Ni and Cr additions on corrosion behavior of cemented carbide in acid salt spray environment were studied by means of acid salt spray test,polarization curve test,scanning electron microscopy and energy spectrum analysis.The results show that WC-Co cemented carbide is prone to electrochemical corrosion due to the low standard reduction electrode potential of the binder phase in acid salt spray environment,resulting in the loss of the binder phase.The additions of Ni and Cr can significantly increase the electrode potential and reduce the polarization current density,resulting in the improvement of the corrosion resistance of WC-Co cemented carbide in acid salt spray solution.SEM and EDS results show that additions of Ni and Cr can reduce the loss of cemented carbide binder phase in acid salt spray solution.