Patent ID: 6669786
Filing Date: 2003-12-30
Classification: C23C

Abstract:
A non-chromate coating process for coating an aluminum surface comprising the steps of:(a) forming a coating layer on said aluminum surface, wherein said coating layer comprises trivalent aluminum ions; and (b) applying a solution to said coating layer, said solution comprising a first metal ion having a trivalent state and a second metal ion having a hexavalent state, whereby said first and second metal ions partially replace said trivalent aluminum ions to form a coating having a self-healing effect; wherein said first and said second metal ions have the same coordination number as said trivalent aluminum ions, and further wherein said first and said second metal ions have ionic radii sufficiently similar in size to the ionic radius of said trivalent aluminum ions such as to allow said partial replacement of said trivalent aluminum ions with said first and said second metal ions.