Patent ID: 7093340

Claim:
A method for making a cook surface comprising the steps of: providing a substrate metal layer selected from the group consisting of stainless steel, carbon steel and titanium wherein said substrate metal layer has a layer of a high heat conductivity metal bonded thereto selected from one of aluminum and copper and defining a clad composite; mechanical buffing the substrate surface; electropolishing the substrate surface to form a bright luster finish on said substrate surface, wherein said electropolishing step provides a surface smoothness value Ra on the order of about 50% less than a smoothness value of the substrate after the mechanical buffing step; cleaning the substrate; and applying by PVD a coating of zirconium nitride to the bright luster finished substrate surface at a temperature between 500°–900° F. (260°–482° C.), whereby no separation occurs between the layers of the clad composite.