2020 年 86 巻 1 号 p. 87-92
This paper discusses the surface modification processing of copper nickel alloy for lead frame using Na2SO4 electrolyzed oxidizing water (hereinafter to as EO water). First, the etching characteristics of Na2SO4 EO water against the test pieces surface of copper nickel alloy was clarified using chemicals and NaCl EO water for comparative immersion experiments. The results showed that as for the etching efficiency, Na2SO4 EO water was superior compared with H2SO4 solution, but inferior to NaCl EO water. Next, by the observation using SEM image, the influence of Na2SO4 EO water on the surface micro shape was clarified. The results indicated that when using Na2SO4 EO water etching residue becomes little compared with H2SO4 solution, and the dimple becomes small compared with NaCl EO water. Lastly, the cleanliness in the outermost surface was clarified by auger spectrum analysis. The results indicated Na2SO4 EO water is same as H2SO4 solution and there was few chlorine contaminations compared with NaCl EO water.
