Method for forming cobalt conversion coating on metal substrate, chemical conversion coating solution and article manufactured by the above method

摘要

(A) It is a method for forming a cobalt conversion coating on a metal base material, and as a result, corrosion resistance and paint adhesiveness are provided. The present invention has been developed as an alternative to the conventional chromic acid method. The method comprises the steps of: (a) preparing a cobalt conversion solution consisting of an aqueous solution containing from about 0.01 mole per liter of soluble cobalt-III hexavalent complex to a solubility limit concentration of the cobalt-III hexavalent complex: and (b ) The metal substrate is contacted with the solution for a sufficient time to form the cobalt conversion coating. Substrates can be aluminum or aluminum alloys as well as Cd plates, Zn plates, Zn-Ni plates, and strength. The cobalt-III hexavalent complex may be in the form of Me _m [Co (R) 6] _n , where Me is one or more selected from the group consisting of Na, Li, K, Ca, Zn, Mg and Mn, m Is 2 or 3, n is 1 or 2, and R is a carlaxylate having 1 to 5 C atoms. (B) chemical conversion for preparing a cobalt conversion coating on a metal substrate, comprising an aqueous solution containing a soluble cobalt-III hexavalent complex at about 0.01 mole per liter of solution to a solubility limit concentration of the cobalt-III hexavalent complex Coating solution. (C) (a) a metal substrate; And (b) an acceptable corrosion and paint adhesion composition comprising a cobalt-charged coating formed on the substrate, comprising up to volume percent aluminum oxide Al ₂ O ₃ , and cobalt oxide CoO, Co ₂ O ₃ , and Co ₃ O ₄ . Coated article.