1. The formulation containing chromic acid 300, sodium hydroxide 40, trivalent chromium 6.2, potassium fluosilicate 5, and strontium sulfate 5 g/l is recommended as a self regulating tetrachromate bath for chromium plating, both decorative and hard. 2. For a decorative copper-nickel-chromium system, the above bath operated at 40'C in the c.d. range 5 to 60 A/dm^2 with a CE of 18.5% is satisfactory. If a faster bath is required, the same may be operated at 30'C in the c.d. range 5 to 22.5 A/dm^2 with a CE of 21.5-28.7%; under these conditions the SRTC is more efficient than the standard bath operated at 50'C. Thus, whether the operating temperature is 30'C or 40'C, we have a self regulating formulation for decorative applications operated at around ambient temperature (30'C).
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