PROCESS FOR PREPARING CHROMIUM CONVERSION COATINGS FOR MAGNESIUM ALLOYS

摘要

Process of coating magnesium alloys to improve the corrosion resistance and adhesive bonding strengths of the alloys. The process comprises treating the magnesium alloys with an acidic aqueous solution comprising, per liter of solution, from about 0.01 to 10 grams of a water soluble trivalent chromium compound, about 0.01 to 10 grams of hexafluorozirconate, about 0.0 to 5.0 grams of at least one hexafluorosilicate and/or a tetrafluoroborate, from about 0.0 to 5.0 grams of at least one water soluble divalent zinc compound and from 0.0 to 10 grams of a water soluble thickener and/or 0.0 to 10 grams of a water soluble surfactant.