缓冲剂对亚硫酸盐-硫代硫酸盐化学镀金液稳定性及镀层形貌的影响

摘要

The effects of four buffer solutions including CH3COOH-CH3COONa, C6H8O7-Na3C6H8O7, C6H8O7-Na2HPO4, and Na2HPO4-NaH2PO4on the stability of sulfite-thiosulfate electroless gold plating bath and the properties of gold coating obtained therefrom were studied. The basic bath composition and process conditions are as follows: Au+(added as Na3Au(SO3)2) 1 g/L, Na2SO312.6 g/L, Na2S2O35H2O 24.9 g/L, pH 6.5, temperature 65℃, and time 5 min. The four buffer solutions are able to improve the stability of the electroless gold plating bath at high temperature and its tolerance to nickel ions and sodium hypophosphite (a reducing agent for electroless nickel plating). The gold coatings obtained from the bath with C6H8O7-Na2HPO4buffer solution exhibit the most uniform thickness, smoothest surface, and best compactness.%研究了CH3COOH-CH3COONa、C6H8O7-Na3C6H8O7、C6H8O7-Na2HPO4和Na2HPO4-NaH2PO4这4种缓冲体系对亚硫酸盐-硫代硫酸盐化学镀金液稳定性和镀层性能的影响.镀液的基本组成和工艺条件为:Na3Au(SO3)2(以Au+计)1 g/L,Na2SO312.6 g/L, Na2S2O3·5H2O 24.9 g/L,pH 6.5,温度65 ℃,时间5 min.4种缓冲体系都能在一定程度上提高镀液的高温稳定性及其对镍离子和化学镀镍还原剂(次磷酸钠)的耐受度.采用C6H8O7-Na2HPO4缓冲体系时,镀金层厚度最均匀,表面最光滑、致密.