Claims
- 1. A method of protecting non-anodized aluminum or aluminum alloy with a non-chromium coating comprising contacting the aluminum or aluminum alloy with an aqueous solution containing as the essential ingredients thereof an alkali metal permanganate and an aluminum nitrate, said aqueous coating solution contains at least 760 ppm of permanganate and about 0.10 to 10.0% of aluminum nitrate, maintaining the pH of the solution at about 2.5 to about 4.0, maintaining the temperature of the solution at about 140.degree. to 170.degree. F., immersing the aluminum or aluminum alloy in the solution for at least 20 seconds to form a protective conversion coating on the aluminum or aluminum alloy and removing any excess coating solution from the aluminum or aluminum alloy.
- 2. The method of claim 1 wherein the aqueous coating solution contains at least about 1.5 gms of sodium permanganate per liter of solution and about 0.5% to about 2.0% by weight of Al(NO.sub.3).sub.3.9H.sub.2 O.
Parent Case Info
This is a continuation in part of my patent application Ser. No. 08/050,841, filed Apr. 21, 1993 now U.S. Pat. No. 5,358,623.
US Referenced Citations (2)
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
50841 |
Apr 1993 |
|