Deposition of yttria-stablized zirconia films using arc ion plating

Arc ion plating is known to be capable of producing crystalline ceramic films at low deposition temperatures and therefore lends itself to the production of functional zirconia films which are commonly used for thermal barrier coatings, fuel cells and gas sensors. In this study, yttria-stablized zirconia (YSZ) films were deposited on Alloy 600 nickel-based superalloy by an arc ion plating system utilizing a single 84Zr-16Y alloy cathode. The working pressure, substrate bias and substrate-to-cathode distance were varied systematically in order to reveal their effects on the growth behavior and microstructure of the YSZ films, which is important when considering future applications. In this study YSZ films with mixed crystalline cubic and tetragonal structures were synthesized at temperatures of about 400 °C without in situ substrate heating. The influence of total pressure was examined by changing the argon pressure whilst maintaining a constant oxygen pressure of 0.6 Pa. Arc motion was found to be stable on the cathode up to a working pressure of 4.0 Pa and the optimum film quality was achieved for deposition in pure oxygen at 0.6 Pa. Film growth rates ranged from 11 to 18 μm/h for all deposition conditions. For both source to substrate distances (12 and 18 cm) the film growth rate increased with negative substrate bias, reaching similar maxima at -400 V, which subsequently decreased on further increase of the bias. By taking account of process parameter effects such as these, it may be possible to optimize the film quality for specific requirements.