- 著者
-
津留 壽昭
木村 哲二
乾 忠孝
- 出版者
- The Surface Finishing Society of Japan
- 雑誌
- 金属表面技術 (ISSN:00260614)
- 巻号頁・発行日
- vol.27, no.3, pp.130-134, 1976
A study was made on electrodeposition of cobalt from cobalt ethylenediamine chelate solution for the purpose of investigating the stability of chelate on pH and the optimum condition in electrolysis. The results obtained were as follows: 1) Ethylenediamine (en) and cobalt ion (II) formed stable chelate compound of (Coen<sub>3</sub>)<sup>2+</sup> in a pH range 8.0-10. 2) Bright cobalt platings were obtained from chelate solutions of pH 3.0-5.0 by the addition of two addition agents, and cathodic current efficiency was found to be decreased. The optimum bath composition for bright cobalt plating was as follows: CoCl<sub>2</sub>⋅6H<sub>2</sub>O (CoSO<sub>4</sub>⋅7H<sub>2</sub>O) 0.05-0.20mol/<i>l</i> (0.1-0.3mol/<i>l</i>), en 0.15-0.60mol/<i>l</i> (0.3-0.9mol/<i>l</i>), HOCH<sub>2</sub>C: CCH<sub>2</sub>OH 0.05g/<i>l</i>, C<sub>10</sub>H<sub>6</sub> (SO<sub>3</sub>Na)<sub>2</sub>⋅2H<sub>2</sub>O 0.03g/<i>l</i>, pH 3.0-5.0, Temperature Room temperature, Cathodic current density 0.8-1.5A/dm<sup>2</sup>. The cathodic current efficiency under the above condition was about 70-80%. 3) The cobalt deposits obtained from Co-en baths were of small grains in crystal structure, and the brightness apparently increased with increasing electrolysis time.