Vapor deposited chrome–copper–chrome laminates for electromagnetic interference/radio frequency interference shields

A patented process for shielding electronic enclosures is discussed relative to both process parameters, as well as the finished electrical and physical properties of the composite structures fabricated. The electrical data were obtained by testing standardized composite squares for shielding effectiveness using the shielded box technique of an independent test laboratory. Physical data were obtained by evaluating the same and/or similar composites for standardized adhesion at Underwriters Laboratories Inc. The specific test battery chosen was Underwriter’s standard ‘‘UL746C.’’ In this case sample composites received both thermal cycling as well as thermal/humidity ‘‘aging’’ before performing standardized adhesion testing. All test panels were evaluated versus a standardized ‘‘control’’ panel of a nickel‐acrylic coating on ABS. The results indicated that ‘‘thin’’ metallic vapor deposited laminates were as effective as ‘‘thick’’ conductive nickel–acrylic coatings for both coating adhesion and coating shielding effectiveness.