感应熔覆Ni60涂层显微组织及耐蚀性

利用两步法,感应熔覆制备了内、外壁Ni60合金涂层钢管.研究了熔覆涂层腐蚀前、后截面显微组织以及腐蚀产物膜的微观形貌特征,利用失重法测量了涂层盐雾、CO2腐蚀速率,定量评价了熔覆涂层的耐腐蚀性能.结果表明:熔覆Ni60涂层全致密,内部均匀分布大量碳化物、硼化物硬质点,涂层与基体之间冶金结合,界面处互扩散区宽度约为8 μm.熔覆Ni60涂层对基体有较好的防腐保护作用,盐雾腐蚀环境下出现锈斑的时间大于150 h,平均腐蚀速率为0.75 g/(m2· h),涂层动态CO2腐蚀相对静态CO2腐蚀更加剧烈,实验温度348 K时,静态腐蚀速率为0.78 g/(m2·h),动态腐蚀速率为1.02 g/(m2·h).

Microstructure and corrosion resistance of Ni60 coating prepared by induction cladding

To improve wear and corrosion resistance of steel pipes,internal and external Ni60 alloy coated steel pipe was prepared by induction cladding.The microstructure of coating and corrosion product film was studied by SEM.Corrosion resistance of the cladding was quantitative evaluated under the condition of salt fog corrosion and CO2 corrosion by weight loss method.The results show that the Ni60 cladding is fully dense with amount of evenly distributed carbides and borides.The interface diffusion area of coating and substrate is about 8 μm.Under the condition of salt fog corrosion,the appearing time of rust is longer than 150 h.The average corrosion rate of Ni60 cladding is 0.75 g/(m2·h),while the corrosion rate under the temperature of 348 K are 0.78 g/(m2·h) and 1.02 g/(m2·h) in the condition of static and dynamic CO2 corrosion,respectively.Ni60 coating has good anti-corrosive protection of carbon steel.