Coating zinc or cadmium to impart corrosion and abrasion resistance

Claim 1

THE PROCESS OF FORMING A VISIBLE CORROSION RESISTANT COATING ON A SURFACE OF ZINC OR CADMIUM OR ALLOYS CONSISTING ESSENTIALLY THEREOF WHICH COMPRISES SUBJECTING THE SAME TO AN AQUEOUS ACIDIC SOLUTION HAVING A PH BETWEEN ABOUT 0.5 TO 2.0 CONSISTING ESSENTIALLY OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF CHROMIC ACID AND SOLUBLE SALTS THEREOF; A COMPOUND SELECTED FROM THE GROUP CONSISTING OF PHOSPHORIC ACID AND SOLUBLE SALTS THEREOF; A COMPOUND SELECTED FROM THE GROUP CONSISTING OF NITRIC ACID AND SOLUBLE SALTS THEREOF AND A COMPOUND SELECTED FROM THE GROUP CONSISTING OF SULFURIC ACID AND SOLUBLE SALTS THEREOF UNTIL A GREEN COATING IS FORMED, THE CHROMATE IONS BEING PRESENT IN AMOUNT OF BETWEEN ABOUT 20 G./1. AND 40 G./1. OF CHROMIC ACID, THE PHOSPHORIC IONS BEING PRESENT IN AMOUNT OF BETWEEN ABOUT 1 AND 15 CC./1. OF PHOSPHORIC ACID AND THE REMAINING MINERAL ACIDS BEING IN AMOUNTS BY VOLUME TO PRODUCE A PH WITHIN ABOUT 0.5 TO 2.0, AND AFTER SAID TREATMENT HEATING THE COATING TO INCREASE ITS ABRASION RESISTANCE.