碳钢表面化学镀Ni-P镀层内应力大、结合强度低从而导致其耐蚀性降低, 限制了其在某些重要零部件的应用。采用化学镀技术在45#钢表面制备了磷含量由低到高的Ni-P梯度镀层,并采用横截面金相法测量了镀层的厚度,利用线性极化曲线和浸泡试验研究比较了该梯度镀层与三种均质镀层的耐蚀性。结果显示,Ni-P梯度镀层在3.5% NaCl溶液中的耐蚀性好于均质的低磷、中磷和高磷镀层, 其耐点蚀性能明显优于均质镀层。

The high innerstress, low bindingforce and poor wear resistance of electroless Ni-P coatings can′t meet the special needs of corrosion resistance of some wear parts yet.In this work, low-P, middle-P, high-P and l-m-h Ni-P gradient coatings were prepared on the surface of 45# steel by electroless plating. The thickness of coatings were measured by cross section metallographic method and the corrosion resistance of four coatings were investigated by linear polarization method and immersion test. The results show that the gradient coatings present better corrosion resistance in 3.5% NaCl solution than homogeneous coatings,and the pitting corrosion resistance is superior to the homogeneous coatings obviously.