Optimization of (Ti,Al)N hard coatings by a combinatorial approach

Combinatorial synthesis and screening is an established technique in the pharmaceutical industry. Recently combinatorial approaches have been made to the screening of superconductive, magnetoresistant and photoluminescent materials [Angew. Chem. Int. Ed., 38(17) (1999) 2494]. Although the development of multicomponent hard coatings by a combinatorial approach could lead to a significant decrease in cost and time, to our knowledge, no paper has been published in this field up to now. In this paper, the deposition and characterization of laterally graded (Ti,Al)N hard coatings with compositions from nearly pure TiN to AlN is presented. The coatings have been deposited by reactive magnetron sputtering, using an aluminum and a titanium target at a low angle to the substrate surface as well as a system of apertures. The relation between composition and oxidation resistance of the ternary films has been investigated. The results illustrate that the combinatorial approach is a powerful and cost effective tool for the development and optimization of new materials for hard coatings.