Chromating solution and chromated metal sheet

摘要

In a chromating solution comprising a water-soluble chromium compound and a reducing agent and in which hexavalent chromium ions produced by dissolution of the water-soluble chromium compound have been partly reduced with the reducing agent to trivalent chromium ions, an oxycarboxylic acid compound is used as the reducing agent. This chromating solution causes neither gelation nor sedimentation of the solution even when hexavalent chromium ions are reduced to trivalent chromium ions at a reduction percentage of more than 50%. The chromating solution and a chromate film formed on a steel sheet may also contain an organic resin, phosphoric acid or a phosphoric acid compound, or a silica sol.