A Study On Methylsulphonate Electroplating Process Of Matt Pure Tin Of Solderability

The electroplated tin-lead alloy has been widely applied in electronic industry for its excellent solderability and whisker-free crystal. But more and more strict laws for banning lead in electronic products were been legislating gradually in many countries or organizations all over the world. Against this background some lead-free electroplating processes have been developed at home and abroad. Among these processes, to electroplate pure tin on electronic components are a leading contender to replace the traditional standard electroplated tin-lead alloy. With transforming electronic components' coatings from the tin-lead alloy into the pure tin, a problem of tin whiskers has re-emerged.An electroplating additive, which is available for electroplating matt pure tin of solderability and can effectively inhibit the tin whisker formation, was developed by electrochemical and chemical methods in the dissertation. The process including the methylsulphonic acid concentration, the bivalent tin ion concentration, the concentration of electroplating additive of matt pure tin, the running temperature and the running current density was determined by Hull Cell tests and electroplating simulated tests.(1) For the low-speed electroplating process of matt pure tin of solderability:methylsulphonic acid 150～210g/Lbivalent tin ion 12 ～ 18g/Lelectroplating additive of matt pure tin 10～80ml/Ltemperature 15 ～25℃Jc 0.5～2.0 A/dm~2(2) For the high-speed electroplating process of matt pure tin of solderability:methylsulfonic acid 200～250g/Lbivalent tin ion 55～75g/L...