한국표면공학회지 (43권6호 297-303)
Investigation of the Effect of Solution Acidity and Organic Additives on the Electrodeposition of Trivalent Chromium Ions
3가크롬 이온의 전착 반응에 용액 산도 및 유기물 첨가제가 미치는 영향 연구
Lee, Joo-Yul;Van Phuong, Nguyen;Kang, Dae-Keun;Kim, Man;Kwon, Sik-Chol;
한국기계연구원 부설 재료연구소 융합공정연구본부;국립 창원대학교 화학과;
Materials Processing Division, Korea Institute of Materials Science;Anastro Laboratory, Department of Chemistry, Changwon National University;
The effect of solution acidity and organic additives, polyethylene glycol (PEG), on the trivalent chromium electroplating was systematically investigated in the view point of electroreduction of trivalent chromium ions and solution stability. It was found that solution acidity controlled at pH 2.5 showed the widest current range for bright electrodeposits in the presence of PEG additives, which reduced the local current intensification at high current densities. Through complex interaction between PEG additives and hydrogen ion, that is, solution acidity, electrode potential was moved in the negative direction in the bulk solution, while it shifted in the positive when electric potential was scanned. In conjunction with electrochemical quartz crystal microbalance (EQCM), it was found that PEG additives had a role in promoting the electron transfer to trivalent chromium ion complexes in bulk solution and their adsorption at the electrode surface as well as interfering with hydrogen ion reduction process below pH 2.5. The PEG additives developed the nodular morphology during electroreduction of trivalent chromium ions with the increase of solution acidity and enhanced its current efficiency by maintaining the consumption of complexant, formic acid, at low speed.
Trivalent Cr electroplating;Solution acidity;Organic additives;