灰铸铁表面Ni60A镍基合金感应熔覆层在H_2SO_4溶液中的腐蚀行为

Corrosion Behavior in Sulfuric Acid Solution of Ni60A Ni-based Alloy Induction Cladding Layer on Gray Cast Iron

用多步感应熔覆法在HT300灰铸铁表面制备Ni60A镍基合金熔覆层,研究了熔覆层的显微组织、物相组成及其在H_2SO_4溶液中的腐蚀行为。结果表明:熔覆层与基体形成了良好的冶金结合;熔覆层主要由γ-Ni以及Ni_3Si、Cr_(1.12)Ni_(2.88)、Ni_3B、Cr_(15.58)Fe_(7.42)C_6等物相组成;熔覆层的电化学腐蚀存在钝化过程,自腐蚀电流密度和腐蚀速率远低于灰铸铁的,熔覆层/H_2SO_4溶液腐蚀体系的总阻抗值更高;在H_2SO_4溶液中熔覆层表面生成了具有钝化效果的Ni_2O_3,显著提高了其耐腐蚀性能。

Ni-based alloy cladding layer was prepared on the surface of HT300 gray cast iron by multi-step induction cladding method.The microstructure,phase composition and corrosion behavior in H2SO4 solution of the cladding layer were studied.The results show that the cladding layer was metallurgically integrated with the substrate.The cladding layer mainly consisted of γ-Ni,Ni3Si,Cr1.12Ni2.88,Ni3B,Cr15.58Fe7.42C6 and other phases.There was a passivated procedure in the electrochemical corrosion of the cladding layer.The free corrosion current density and corrosion rate of the cladding layer were far below those of gray cast iron.The cladding layer/H2SO4 solution corrosion system had a higher total resistance value.Ni2O3 with passivation effect was formed on the surface of cladding layer in H2SO4 solution,and improved the corrosion resistance of the cladding layer significantly.