Abstract

Double-layer TiN/PSZ film coatings were deposited on Si wafers and WC-Co cutting tools from Ti-, Zr-, and Y-alkoxide solutions by thermal plasma chemical vapor deposition (CVD) containing water vapor. The partially stabilized zirconia (PSZ) layer was coated on a TiN film by oxidation of Zr- and Y-alkoxides with H₂O supplied by both constant and step-wise methods. Double-layer TiN/PSZ coatings deposited on Si wafers and WC-Co by the two H₂O supply methods were approximately 2 μm thick. TEM observation showed that the interface between the TiN and PSZ in the double-layer TiN/PSZ formed by the step-wise H₂O supply is more adhesive than under constant H₂O supply. Double-layer TiN/PSZ films coated on WC-Co substrates by the step-wise supply exhibited good crater wear resistance, comparable to a commercial double-layer TiN/Al₂O₃ coating by thermal CVD.