The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 05, 1995
Filed:
Mar. 11, 1994
Matthias P Schriever, Kent, WA (US);
The Boeing Company, Seattle, WA (US);
Abstract
(A.) A process for forming a cobalt conversion coating on a metal substrate, thereby imparting corrosion resistance and paint adhesion properties. The invention was developed as a replacement for the prior art chromic acid process. The substrate may be aluminum or aluminum alloy, as well as magnesium and its alloys, Cd plated substrates, and Zn plated substrates. The cobalt-III hexacoordinated complex may be present in the form of Me.sub.3 [Co(NO.sub.2).sub.6 ] wherein Me is one or more of Na, K, and Li. (B.) A chemical conversion coating solution for producing the cobalt conversion coating on a metal substrate, the solution being an aqueous solution having a pH of about 7.0 to 7.2 and containing a soluble cobalt-III hexacoordinated complex, the concentration of the cobalt-III hexacoordinated complex being from about 0.1 mole per gallon of solution to the saturation limit of the cobalt-III hexacoordinated complex. The cobalt conversion solution may be prepared by a bath makeup sequence including the steps of: (a) dissolving a metal nitrite salt; (b) dissolving an accelerator such as NaI; (c) dissolving a cobalt-II salt; and (d) then adding an oxidizer such as H.sub.2 O.sub.2.