钕铁硼化学镀Ni-Mo-P镀层的形貌和耐腐蚀性能

Morphology and Corrosion Resistance of Ni-Mo-P Coatings on NdFeB Prepared by Electroless Plating

向化学镀溶液中加入不同质量浓度的硫酸铈,在钕铁硼表面化学镀制备了四种Ni-Mo-P镀层。采用全浸实验和电化学实验考察了四种镀层的耐腐蚀性能,同时表征了四种镀层腐蚀前后的微观形貌,并与钕铁硼进行对比。结果表明:四种Ni-Mo-P镀层相比于钕铁硼具有良好的耐腐蚀性能,但硫酸铈质量浓度变化对镀层的耐腐蚀性能以及腐蚀前后的微观形貌有一定影响。适当的增加硫酸铈质量浓度有利于改善镀层的微观形貌,使镀层的腐蚀倾向降低,从而提高耐腐蚀性能。当硫酸铈质量浓度为45 mg/L得到的镀层相比于其它镀层具有更好的耐腐蚀性能。但硫酸铈质量浓度超过45 mg/L会使镀层的微观形貌呈现恶化的趋势,耐腐蚀性能下降。

Cerium sulfate of different mass concentration was added to the electroless plating bath,and four kinds of Ni-Mo-P coatings were prepared on the surface of NdFeB by electroless plating.The corrosion resistance of the four coatings and NdFeB was investigated by full immersion test and electrochemical test,and the microstructure of four kinds of Ni-Mo-P coatings and NdFeB before and after corrosion was characterized.The results showed that four kinds of Ni-Mo-P coatings have better corrosion resistance than that of NdFeB,but the variation of mass concentration of ceric sulfate has a certain effect on the corrosion resistance and micromorphology of the coatings before and after corrosion.Appropriate increase of the mass concentration of ceric sulfate was beneficial to improve the micromorphology of the coatings,thus reduce the corrosion tendency and then improve the corrosion resistance.The coating obtained with 45 mg/L ceric sulfate has better corrosion resistance than that of the other coatings.However,when the mass concentration of cerium sulfate exceeds 45 mg/L,the microstructure of the coating tends to deteriorate,resulting in the decline of corrosion resistance.