New Routes in the Preparation of Mechanically Hard Films

Superhard nitride superlattice coatings with nanometer-scale multilayers have hardnesses exceeding 50 gigapascals, making these films highly resistant to abrasion. The nitride superlattice films can be deposited economically by reactive sputtering in production-size equipment on a variety of substrates. A model for the superlattice strength enhancement has been developed that accurately predicts which materials can be used together to produce the enhanced hardness. Advancements in sputtering technology-specifically, pulsed dc power and reactive-gas partial-pressure control-make it possible to reactively deposit nonconducting oxide films at high deposition rates. This technology is being used along with the superlattice strength model in the development of oxide superlattice films.