High-temperature stability and interfacial reactions of Ti and TiN thin films on Al2O3 and ZrO2

Abstract

Abstract Metallic thin films are used in many applications to modify ceramic surfaces. However, during subsequent processing, chemical interactions may change the properties of the coating. In addition, differences in thermal expansion can lead to delamination of the coating. In this study, titanium and titanium nitride thin films were deposited via physical and chemical vapor deposition (PVD and CVD, respectively) on alumina- and yttria-stabilised zirconia substrates, before being heat-treated at 1200 °C or 1500 °C in static argon atmosphere and analysed via SEM, EDS and XRD to investigate the effect of temperature on the thin films. It was shown that the chemical interactions between TiN and both Al 2 O 3 and ZrO 2 are weak. However, partial delamination of the TiN coating on alumina was observed after both annealing temperatures. The TiN coating on zirconia remained adherent. In contrast, the Ti coatings underwent a transformation to cubic TiO on both oxide substrates. This was due to partial reduction of the ZrO 2 to ZrO 2 − x and dissolution of the Al 2 O 3 , which leads to a Ti 3 Al 0.9 O 1.1 interlayer. The TiO coating which formed remained adherent on the alumina at both annealing temperatures, but delaminated from the ZrO 2 substrate after annealing at 1500 °C.