Patent ID: 7204871
Filing Date: 2007-04-17
Classification: C09D,C23C

Abstract:
1. A process for forming a coating on a metal substrate comprising: contacting the substrate with a molybdenum-containing solution having a pH of between 3.5 and 5, inclusive, and containing an acid, with the proviso that the acid is not nitric acid at a temperature between 30 and 75 degrees Celsius such that a yellow coating develops from between 20 and 300 seconds after contact therewith wherein molybdenum is the only metal responsible for the yellow coating and present within said solution as a molybdate or M 0 (VI)Q m X n where X is in each instant independently fluorine, chlorine or bromine; m is an integer value of 1 or 2; and n is an integer value of 2 or 4; 2m+n=6.