复合结构Ni-P非晶态镀层在H_2S/CO_2环境中的耐腐蚀性能

Corrosion resistance of Ni-P amorphous composite coating in the environment containing H_2S/CO_2

通过在同一镀液中改变温度、pH值和施加电流完成化学镀和电镀过程,在普通碳钢基体上得到电位差高于160 mV的复合结构的非晶态Ni-P合金镀层。采用SEM、电化学测试设备及专门的腐蚀环境试验箱,研究了该复合镀层在H2S/CO2腐蚀气氛中的耐腐蚀行为。结果表明:所制备的复合结构Ni-P非晶态镀层在H2S/CO2腐蚀环境中,100 h后镀层表面出现均匀的硫化物腐蚀膜,300 h后镀层表面出现腐蚀裂纹,并沿着与基体表面平行的方向扩展、剥离,在电镀层剥离处磷元素的相对含量增加。所制备的12μm厚的复合叠加结构Ni-P非晶态镀层的耐腐蚀性能优于25μm厚的普通化学Ni-P非晶态合金镀层。

A multilayer amorphous Ni-P composite coating with a potential difference above 160mV was prepared in the same bath by varying the temperature, pH value and electric field alternately. The anti-corrosion behavior of the composite coating was studied in the environment with H2 S and CO2 , and the results show that the terrace amorphous Ni- P composite coating performed well in corrosion- resistance in the environment with H2 S and CO2. An even corrosive film formed on the surface of the composite terrace coating after 100h. Corrosive cracks appeared on the composite coating＇s surface after 300h, and the cracks expanded along the parallel direction of the base. The enrichment of phosphorus occurred in the places where the electrodeposited coating was deprived. The corrosion results indicated that this multilayer Ni-P coating of 12 μm thickness possessed better anti-corrosion properties than the plain electroless coating of 25μm.