Vacuum are deposition of conductive wear resistant coatings on polymer substrates

Thin conductive wear resistant metal/ceramic coatings were deposited onto p olysulfone S2010 substrates using a triple-cathode vacuum are plasma source connected to a magnetized plasma duct. Various combinations of two-layer c oatings having an inner metallic conductive layer of Ti, Zr, Cu, Ag or Al a ttached to the plastic, and an external wear resistant layer of TiN or ZrN, were studied and evaluated. It was shown that bi-layer Ti/TiN and Ti/ZrN coatings had good adhesion to the substrate and low wear rate, but their electrical surface resistivity w as high (3-6.6 Ohm/square). Cu, Ag and Al metal sublayers had a superior ad hesion to the polymer substrate and low surface resistivity (less then 0.1 Ohm/square). However, the deposition of a TiN layer on Ag caused immediate coating delamination from the substrate. In the case of Ag/ZrN coatings, wh ich initially possessed good adhesion to the substrate, cracking and delami nation of ZrN at the Ag/ZrN interface was observed after some time (1-7 day s), while the Ag layer remained adherent to the substrate. In the cases of Cu/TiN and Cu/ZrN coatings, the nitride layers had poor adhesion to the Cu layer. The best results were obtained for Al/ZrN coatings, which had low su rface resistivity (0.08-0.11 Ohm/square) with good adhesion of the Al layer to the substrate and of the nitride layer to Al. (C) 1999 Elsevier Science S.A. All rights reserved.