化学镀镍磷合金镀层封孔处理工艺及性能

Technique and properties of sealing treatment on the electroless Ni-P alloy coatings

研究了一种新型的镍磷合金镀层镀后处理工艺，即在常温下．采用化学的方法对镍磷合金镀层进行封孔处理。利用不同施镀时间的镍磷合金镀层模拟具有不同孔隙率的镍磷合金镀层，并采用涂膏法对封孔前、后镍磷合金镀层的孔隙率进行了测定。结果表明：经封孔处理的镍磷合金镀层的孔隙率大幅度下降。采用动电位极化技术测试了镍磷合金镀层封孔处理前、后的极化曲线，发现：经封孔处理后的镍磷合金镀层，腐蚀电位正移，腐蚀电流减小。通过扫描电镜观察了封孔处理后镍磷合金镀层的表面形貌，可见：经封孔处理后的镍磷合金镀层表面形成了一层保护膜，使镍磷合金镀层的孔隙得以封闭。

A new post-treatment technique that Ni-P alloy coating can be sealed at ambient temperature by chemical method has been investigated and developed. By using the Ni-P alloy coatings with different time of plating, the coatings with different porosity were stimulated, then the porosity of the coatings was detected by standard porosity detection method. The results show the porosity of the coatings decreased greatly after the coatings were sealed. The potentiodynamic polarization curves of the sealed and unsealed coatings indicated that the corrosion potential of the sealed coatings shifted towards positive direction and corrosion current density decreased. The SEM morphology of the sealed coatings confirmed that there was a protective film on the surface of the Ni-P alloy coatings, which effectively sealed the pores of the coatings.