Patent ID: 9303546
Filing Date: 2016-04-05
CPC Classification: B05D,C25D,F01N,Y10T

Claim Text:
1. A method for preventing discoloration of at least one metallic surface comprising a first surface on a first metallic material above an automobile engine, and a second surface on a second metallic material disposed above the first metallic material, the method comprising: applying to the first and second metallic surfaces a clear lacquer that has an oxygen barrier, thereby sealing the first and second metallic surfaces against oxygen contact; and stoving the sealed first and second metallic surfaces with the lacquer thereon at a temperature in a range of 300° C. to 500° C. to form a permanently effective oxygen barrier; wherein at least part of the first metallic material is substantially impermeable to air and moisture, and wherein at least parts of the second metallic material are formed with a plurality of openings therethrough for permitting upward flow of heat away from the engine; and wherein the step of stoving is carried out for the first metallic material under a protective atmosphere of nitrogen, and wherein the step of stoving is carried out for the second metallic material under an air atmosphere.