论文部分内容阅读
采用直流电沉积的方法在低碳钢表面制备了一层Ni-W合金镀层,研究了pH值对电沉积Ni-W合金镀层结构及其耐蚀性能的影响。结果表明:在硫酸盐-柠檬酸镀液体系中可直接沉积一层均匀致密的Ni-W合金层,pH值小于7的镀液沉积得到纳米晶结构的Ni-W镀层;pH值大于7时,镀层为非晶态结构。Ni-W合金层的硬度主要由镀层中W含量所决定,镀液pH值为5.5时所沉积的Ni-W镀层中W含量最高,镀层的硬度最高(753 HV);在3.5%(质量分数)NaCl溶液中,Ni-W合金层均表现出比低碳钢更低的电化学活性,对基体具有良好的保护作用。在所有的Ni-W合金镀层样品中,非晶态镀层由于表面易发生钝化而具有更加优异的耐蚀性能,其中镀液pH值为7.5时所沉积的镀层具有最优的耐蚀性能。
A layer of Ni-W alloy coating was prepared on the surface of mild steel by direct current deposition. The effect of pH value on the structure and corrosion resistance of electrodeposited Ni-W alloy coating was studied. The results show that Ni-W alloy layer with nanocrystalline structure can be obtained by depositing a layer of uniform and dense Ni-W alloy layer in the sulfate-citric acid bath system. When the pH value is greater than 7 , The coating is amorphous structure. The hardness of the Ni-W alloy layer is mainly determined by the W content in the coating. The W content of the Ni-W coating deposited at pH 5.5 is the highest and the hardness of the coating is the highest (753 HV) ) NaCl solution, the Ni-W alloy layer showed a lower electrochemical activity than that of mild steel and had a good protective effect on the matrix. In all samples of Ni-W alloy coating, the amorphous coating has more excellent corrosion resistance due to the passivation of the surface, and the coating deposited at pH 7.5 has the best corrosion resistance.