Surface Modification Processing of Alloy 42 Using Electrolytic Oxidizing Water

This paper discusses the surface modification processing of alloy 42 for lead frame using electrolytic oxidizing water (hereinafter it is referred as EO water). Firstly, the etching experiments were carried out by immersion in Na2SO4 EO water and NaCl EO water, while comparing with H2SO4 solution and HCl solution. The results showed that Na2SO4 EO water has a stronger etching effect than H2SO4 solution, and NaCl EO water has a stronger etching effect than HCl solution. Furthermore, Na2SO4 EO water has almost the same etching effect as NaCl EO water. In addition, compared with Na2SO4 EO water, the change in etching rate for NaCl EO water is slightly larger as the electrolytic current increases. And compared to chemicals, EO water has a weak selective etching effect. As the immersion time increases, the etching rate for both Na2SO4 EO water and NaCl EO water decreases slightly. Next, an experiment was conducted to examine the roughening effect on the rolled surface of Alloy 42. The results showed that compared with H2SO4 solution and HCl solution, Na2SO4 EO water and NaCl EO water has a stronger roughening effect on the rolled surface of alloy 42. By this study, we received the suggestion that Na2SO4 EO water and NaCl EO water could be applied to the surface modification processing of alloy 42 for lead frame.