公开(公告)号：US06190464B1

公开(公告)日：2001-02-20

申请号：US09161414

申请日：1998-09-24

申请人： Yukio Uchida ,  Hirofumi Taketsu ,  Shinya Furukawa

发明人： Yukio Uchida ,  Hirofumi Taketsu ,  Shinya Furukawa

IPC分类号： C23C2226

CPC分类号： C23C22/33 ,  C23C22/30 ,  Y10T428/31678

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.