[pcm81]

Usually chromic acid CrO3 is used in chomium electroplating and Potassium di-Chromate K(CrO3)2 is used in chromate conversion of zinc plating. I am wondering if Aqueous solutions of these two chemicals can be used interchangeably for these 2 processes. I believe Sulfuric acid is also used i the solutions and naturally concentration for electroplating bath will be different from concentration for zinc/chromium conversion bath.

[chenbeier]

Pottasium dichromate is K₂Cr₂O₇, what is equal to K₂CrO₄*CrO₃ (pottassium chromate  plus one (chromic-VI-oxid) chromic acid molecule.
In plating industry the solution is acidified with sulfuric acid and its call chromic sulfuric acid.

K₂CrO₄*CrO₃ + H₂SO₄ => 2 CrO₃ + K₂SO₄ + H₂O

Higher concentration of the compound is produced directly using CrO₃

[pcm81]

Pottasium dichromate is K₂Cr₂O₇, what is equal to K₂CrO₄*CrO₃ (pottassium chromate  plus one (chromic-VI-oxid) chromic acid molecule.
In plating industry the solution is acidified with sulfuric acid and its call chromic sulfuric acid.

K₂CrO₄*CrO₃ + H₂SO₄ => 2 CrO₃ + K₂SO₄ + H₂O

Higher concentration of the compound is produced directly using CrO₃

Tanks. That actually makes sense. I actually have chomium plating solution CrO3 inH2O (33oz of CrO3/Gal + 0.33oz of H2SO4/gal of H2O) and was debating if i can use that for chromium conversion coating of zinc.