汽车用6061铝合金化学镀Ni-W-P合金镀层工艺的研究

先对汽车用6061铝合金进行磷化处理,再在其表面化学镀Ni-W-P合金镀层。研究了还原剂次磷酸钠的质量浓度对化学镀Ni-W-P合金镀层性能的影响。结果表明:随着次磷酸钠的质量浓度的增加,化学镀Ni-W-P合金镀层的沉积速率和显微硬度均呈现出先增大后减小的趋势。然而,过量的次磷酸钠会导致析氢严重,破坏镀液的稳定性。化学镀Ni-W-P合金镀层表面由大量胞状结构组成。当次磷酸钠的质量浓度为30 g/L时,化学镀Ni-W-P合金镀层表面呈现出明显的非晶态特征,并且具有最佳的耐蚀性。

Study on Electroless Plating of Ni-W-P Alloy Coatings on 6061 Aluminum Alloy for Automobile

Electroless Ni-W-P alloy coatings were prepared after phosphating treatment of the 6061 aluminum alloy for automobile.The effect of the mass concentration of sodium hypophosphite(reducing agent)on the properties of the electroless Ni-W-P alloy coatings was studied.The results showed that with the increase of the mass concentration of sodium hypophosphite,the deposition rate and microhardness of the electroless Ni-W-P alloy coatings increased first and then decreased.However,excessive sodium hypophosphite will lead to a large amount of hydrogen evolution and destroy the stability of the plating bath.The surface of electroless Ni-W-P alloy coating was composed of a large number of cellular structures.When the mass concentration of sodium hypophosphite was 30 g/L,the electroless Ni-W-P alloy coating exhibited obvious amorphous characteristics and possessed the best corrosion resistance.