电沉积Ni-Cr合金工艺研究

Electrodepositing Technology of Nickel- Chromium Alloy

含有一定量Cr的Ni-Cr镀层具有良好的耐磨、耐腐蚀性能。选取柠檬酸钠作为配位剂,用动电位扫描法研究了电沉积Ni-Cr合金时的阴极行为,同时对镀层的耐腐蚀性进行了试验。试验结果表明:镀液中加入配位剂柠檬酸钠可以提高阴极极化;pH值、阴极电流密度、配位剂对镀层中铬含量影响较大,在一定范围内增大pH值,增加配位剂的用量,提高电流密度,有利于提高镀层中铬的含量,最佳工艺条件为pH值为2.5,阴极电流密度为25A/dm2,镀液中柠檬酸钠的含量为35g/L,镀层中铬质量分数为20%左右时,Ni-Cr合金镀层的耐腐蚀性能最好。

Choosing sodium citrate as complexing agent, the cathodic behavior in Ni-Cr alloy eleetrodepositing was studied by dynamic potential method, as well as the corrosion resistance of plating was studied experimentally. The resuits show that the addition of sodium citrate eomplexing agent increases the cathodic polarization, and the chromium content inthe plating depends on the pH value, cathodic current densily and complexing agent. The ehromium content increases with the increasing of the pH value, complexing agent concentration and current density within limits. The optimal procvss conditions are pH is 2.5, current density i, 25 A/dm^2 and the concentration of sodium citrate is 35 g/L. The corrosion resiTANCE of Ni-Cr alloy plating is the best as the chromium content in the plating is about 20wt%.