Metastable Ti1-xAlxN films were deposited on HSS substrates by means of MSIP with one compound target, MSIP with two separate targets (graded films), and AIP in a new developed pulsed bias mode to study the influence of different deposition techniques and film compositions on the film properties, their oxidation resistance and mechanical properties. Therefore, films were analyzed in the as-deposited and oxidized state (1 h, 800 C) with respect to their composition, structure, morphology, binding states of the components, micro-and nanohardness, adhesion, and impact resistance by EPMA, XPS, AES, XRD, HEED, SEM, micro- and nanohardness tests, scratchtest, and impact test. The result was the providing of tailored films with special properties: a high temperature oxidation resistant Ti0.38Al0.62N MSIP film, a Ti0.55Al0.45N AIP film for applications at high mechanical stresses and a Ti0.46Al0.54 film appropriate for a combination of the two stress conditions.
The influence of different low-temperature vapour deposition techniques, namely Magnetron Sputtering Ion Plating, Random Arc Ion Plating, metal organic CVD and Plasma Enhanced CVD on the properties of metastable hardcoatings on tools under thermal chemical and mechanical stress will be investigated, taking (Ti, A1)N as a typical example.
Due to industrial relevance of this coating system, the product quality will be checked by a complex testing procedure. The main selection criteria for the life time of these metastable coatings will be transformation stability, mechanical properties and oxidation resistance.
The different film properties will be examined by modern nanotechnonoly analyses and various mechanical test methods both before and after oxidation. Oxidation kinetics will be studied by thermogravimetry. This new approach allows quantitative correlations to be determined between the preparation method, morphology, chemical layer composition, transformation, oxidation and mechanical behaviour.
The project will offer a methodical approach in the design and optimization of metastable hardcoatings for applications preferably in the cutting tool industry, where conditions of high thermal stress in oxidizing atmosphere at elevated temperatures are common.
Funding SchemeCSC - Cost-sharing contracts