Na₂SO₄電解酸化水を用いたコバール合金の表面改質処理

抄録

This paper discusses the surface modification processing of kovar alloy (Fe-29.72wt%Ni-16.28wt%Co) by Na₂SO₄ electrolyzed oxidizing water (hereinafter referred to as EO water). First, the etching effect of Na₂SO₄ EO water on the surface of kovar alloy was clarified by comparative experiments of chemicals and NaCl EO water. The comparative study showed that as for the etching effect on the surface of kovar alloy, Na₂SO₄ EO water was superior to H₂SO₄ solution, but inferior to NaCl EO water. Next, by the observation using SEM image, the influence of Na₂SO₄ EO water on the surface shape of kovar alloy was clarified. The results indicated that when using Na₂SO₄ EO water, the surface of polished test pieces which had not been heat-treated becomes smooth, but in the test pieces surface which had been heat-treated, a lot of dimples had occurred. When using the supersonic together with one of Na₂SO₄ EO water or NaCl EO water, the surface shape became smooth. Lastly, as for the test pieces after heat treatment, the surface oxidation layer removal experiment by the immersion was carried out. The results showed that Na₂SO₄ EO water could remove the surface oxidation layer like H₂SO₄ solution approximately. However, thin surface oxidation layer might be formed when using Na₂SO₄ EO water. By this study, we received the suggestion that Na₂SO₄ EO water could be applied to the surface treatment such as the etching of kovar alloy.