Patent ID: 8563487

Claim:
A conversion coating comprising potassium, phosphorus, nitrogen, and one or more non-alkaline metals, wherein said conversion coating is produced by a process comprising the steps of: 1) forming a solution of water with phosphoric acid or sulfuric acid; 2) thereafter adding ammonium hydroxide slowly to the solution of step 1) over a period of at least 10 minutes; 3) thereafter adding an alkali metal hydroxide in water to the solution produced by step 2); 4) thereafter adding ammonium hydroxide to the solution produced by step 3) to bring the pH to 10-11; 5) thereafter adding potassium hydroxide to the solution produced by step 4) to bring the pH to 14; and 6) adding one or more non-alkaline metal salts to the solution produced by step 5), wherein the solution provided by step 6) forms a conversion coating on a surface when applied to the surface without the use of applied external electromotive force, and wherein said conversion coating contains potassium, phosphorus, nitrogen, and one or more non-alkali metals.