Abstract
A chromium plating bath principally composed of chromic anhydride with a large content of fluosilicate (K2SiF6 of 3-55g/l) was studied with respect to the current density.
The following results were obtained:
(1) The solubility of potassium fluosilicate in chromic acid solution was increased by means of preliminary electrolysis.
(2) In the electrolysis for an extremely short time, the current efficiency was always higher than that of the Sargent Bath. However, the efficiency was above 50% on the side of higher temperature and higher current density.
When the time for electrolysis was longer, it was difficult to maintain such a high current efficiency, but the efficiency was likely to be higher than that of the Sargent Bath.
(3) This plating had a wider range of brightness than the Sargent Bath. Burnt deposits were not produced in this plating even under a high current density as 200amp./dm2.
