D-chromium electrolyte (tetrachromium electrolyte)

The name D-chromium electrolyte (also called tetrachromiumate electrolyte or tetrachromium electrolyte) is used because the electrolyte is well suited for direct chromium plating of brass and zinc. This is done by neutralizing chromium (VI) oxide with NaOH, which significantly reduces the aggressiveness of brass and zinc. Chrome plating is therefore possible without copper plating or nickel plating.

Example approach:

300 – 400 g/L Chromium (VI) oxide
60 g/L NaOH
0,7 g/L Sulphuric acid

Temperature: 16-22°C
Current density: 20-80 A/dm2
Efficiency: 30-37%.

The precipitations have a low hardness, are mouse-grey and must be polished.

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