ギ酸を含む2価クロム電解溶からのクロム電析 [in Japanese] Electrodeposition of Chromium from Divalent Chromium Baths Containing Formic Acid [in Japanese]
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The electrodeposition of chromium from divalent chromium based baths has not been thoroughly investigated, due to the highly transient and unstable nature of Cr (II) ions. The electrodeposition of chromium from a variety of divalent chromium baths was examined to establish conditions suitable for chromium plating. Divalent chromium baths were prepared by electrolytic reduction of aqueous Cr<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> solution using a titanium cathode. Lustrous chromium deposition was obtained by electrodeposition at a cathode potential of -1.1V vs SHE, using aqueous 0.8kmol m<sup>-3</sup> CrSO<sub>4</sub> -2.0kmol m<sup>-3</sup> KCl-0.1kmol m<sup>-3</sup> HCOOH (pH 1.8). For 30min of deposition, the average current efficiency for chromium deposition was 25.4%. The average deposit thickness was 10.8μm. The HCOOH concentration suitable for chromium deposition from divalent chromium baths, is much lower than that from trivalent chromium bathes. The main role of the organic acid is to control the pH in the vicinity of the cathode surface.
- Jitsumu Hyomen Gijutsu
Jitsumu Hyomen Gijutsu 47(3), 245-249, 1996-03
The Surface Finishing Society of Japan