PURPOSE: A primer coating designed so as to improve adhesion between a metallic substrate and a sputtered metal and decrease the change with time thereby preventing peeling off, comprising, as a principal film-forming component, a thermosetting vinyl-urethane type resin.

CONSTITUTION: A coating comprising, as a principal film-forming component, a thermosetting vinyl-urethane type resin. As said urethane type resin, there can be used a resin prepared by addition-polymerizing a monomer contg. urethane linkage or urea linkage prepared by reacting a polyisocyanate with a hydroxyl group-containing compound such as an alcohol, a polyhydric alcohol or a carboxylic acid. In use, said primer coating is applied to the surface of a metallic substrate such as aluminum or iron, and cured by heating into a film which adheres well to the substrate, and then a metal such as chromium or aluminum is deposited onto the surface of the film by sputtering. Therefore, secure and strong adhesion between the film and the metallic substrate can be obtained.