To provide a method for forming a chemical conversion coating superior in corrosion resistance and adhesiveness on the surface of aluminum or an aluminum alloy, without using harmful hexavalent chromium and fluorine compound.
The method for forming the highly corrosion resistant chemical conversion coating containing no hexavalent chromium and fluorine on the surface of aluminum or an aluminum alloy comprises the steps of: forming a zinc film on the surface of aluminum or an aluminum alloy by contacting the surface of aluminum or an aluminum alloy with an alkaline solution containing zinc ions as a main component; and forming the chemical conversion coating free from hexavalent chromium and fluorine on the surface of aluminum or an aluminum alloy having the zinc coating formed thereon, by contacting the surface of aluminum or an aluminum alloy having the zinc coating formed thereon, with a chemical conversion coating solution free from hexavalent chromium and fluorine.
Fumiaki Otsuka
Sadao Kumakura
Shishido Kaichi
Toshio Imajo
Nobuo Ogawa
Village shrine Atsuo
Takaki Nishijima
Atsushi Hakoda