Influence of Silicon Content on the Performance of Multilayer Diamond-like Carbon Coatings

摘要

Multilayer diamond like carbon coating consisting of a-Si:H (hydrogenated amorphous silicon) /silicon containing a-C:H (hydrogenated amorphous carbon)/a-C:H layers were deposited by conventional r.f. (13.56 MHz) glow discharge plasma enhanced chemical vapour deposition (PECVD) technique. These coatings were realized as protective multilayer coatings; involving a-Si:H as interfacial layer, silicon containing a-C:H as bulk layer and hard a-C:H as top layer. Influence of silicon in the bulk layer on the performance of these multilayers structures was studied. These coatings were found to be smooth, sufficiently hard and adhesive to non carbide forming substrates like steel, plastic, glass etc. Stress per unit hardness values of these films were determined as a function of silane partial pressure and found to be minimum at 0.25%. Also a coating consisting of six layers of a-Si:H and a-C:H alternatively was deposited to make a comparison.