Co^(2+)与(Co^(2+)+Ni^(2+))摩尔浓度比对Ni-Co-P合金化学镀层组织与性能的影响

Effect of Molar Ratio of Metallic Ions on Microstructure and Corrosion Resistance of Electroless Ni-Co-P Alloy Coatings

通过改变化学镀液中金属离子Co2+与(Co2++Ni2+)的摩尔浓度比获得了不同的Ni-Co-P合金化学镀层。研究了钴的引入对Ni-Co-P合金镀层的沉积速率及组织性能的影响。结果表明:随着Co2+与(Co2++Ni2+)摩尔浓度比的增加,镀层的沉积速率不断下降,镀层中P含量逐渐减小,镀层表面的胞状组织由大到小;镀层硬度随Co2+与(Co2++Ni2+)摩尔浓度比的增加先升高后降低,Co2+与(Co2++Ni2+)摩尔浓度比为0.4时,硬度最大达554.12HV,镀层具有优良的耐硫酸腐蚀性能,Co2+与(Co2++Ni2+)摩尔浓度比为0.6时,镀层耐蚀性最强。

Electroless Ni-Co-P alloy coatings with different compositions were obtained by varying the metallic ion ratio ([Co2+]/[Ni2+ + Co2+]).The effect of introducing Co on plating rate and microstructure and properties of the Ni-Co-P al-loy coatings was investigated.Results show that the plating rate decreases with increasing ratio of [Co2* ]/[Ni2++ Co2+] ,and the cellular structure of the coating tends to become smaller there-with.The hardness of electroless Ni-Co-P alloy coatings initially increased but then decreased with increasing metallic ion ratio [Co2+]/[Ni2+ +Co2+ ].The electroless Ni-Co-P alloy coating obtained at [Co2+ ]/[Ni2+ +Co2+ ] of 0.4 had the highest hard-ness and excellent corrosion resistance to sulfuric acid,and the coating prepared at a metallic ion ratio of 0.6 possessed the best corrosion resistance.