Electrical contact resistance of titanium nitride coatings for electromagnetic shielding applications

Abstract

Coating materials are typically applied to aluminum alloys, steel, and brass components used in electromagnetic shields in order to provide better corrosion and wear protection for the substrates, and to produce low contact resistance at mated contact joints. This is especially important for contacts which are periodically operated in aggressive environments, such as the doors and access panels on mobile communications facilities used by the military in the field. In this work, the contact resistance of titanium nitride (TiN) coated aluminum alloy 6061-T6, prepared using reactive ion plating, is compared to chromate conversion coated and bare aluminum alloy 6061-T6 contacts when mated to a typical electromagnetic gasket as a function of cyclic make-and-break loading of the contacts. An outline of the coating process and contact resistance test method is presented, along with details of comparative contact resistance results of the coated contacts. It is concluded that 5 μm thick TiN coatings have significantly lower contact resistance than comparable chromate conversion coated or bare aluminum alloy 6061-T6 contacts when cycled through several thousand contact closures.