Effect of microstructure on the mechanical behavior of reactive magnetron sputtered Al2O3/TiO2 multilayer ceramics

Abstract

Mechanical characteristics of reactive magnetron sputtered Al 2O3-TiO2 multilayer ceramics were studied. Tailored mechanical properties such as moderately high hardness and reasonable toughness were achieved through varying sputtering process parameters resulting in microstructural control at nano-scale. Interchanging Al2O 3 and TiO2 layers with a single layer thickness of ∼65-70 nm were deposited on single crystal alumina (sapphire) substrates to form the multilayer structure composed of 10 layers. Deposition pressure was systematically changed throughout the process to obtain variety of microstructures. Nanostructured Al2O3 and TiO2 layers with a high degree of uniformity and interlayer bonding were obtained. The effect of the deposition pressure on the microstructure. and hence the ensuing physical characteristics of the multilayer ceramics were investigated. Resulting physical property sets were discussed in relation to the nanometer-order controlled microstructures. Potential of the nanostructured Al2O3-TiO2 multilayer ceramics for advanced engineering applications in terms of their processing and capacity for improved mechanical properties were addressed. © 2008 The Japan Institute of Metals.