Titanium aluminum nitrides
Titanium aluminum nitride (TiAlN, AlTiN or Ti-Al-N for short) stands for a group of metastable hard material layers consisting of the metallic elements aluminum (Al), titanium (Ti) and the non-metal nitrogen (N). The designation AlTiN is used for materials with an Al / Ti ratio> 1 (in at.%).
Typical composition
Essentially, 4 different compositions with regard to the metal content in the layers are deposited industrially using the PVD process (data in atomic percent based on the metal atoms 100%):
- Ti50Al50N (industrial introduction by the company CemeCoat (now Cemecon), Aachen, FRG, group around T. Leyendecker approx. 1989)
- Al55Ti45N (industrial introduction by Metaplas Ionon (now Sulzer Metaplas), Bergisch Gladbach, FRG, group around J. Vetter 1999)
- Al60Ti40N (industrial introduction Kobe Steel, Kobe, Japan 1992)
- Al66Ti34N (industrial introduction by Metaplas (now Sulzer Metaplas), Bergisch Gladbach, FRG, group around J. Vetter 1996).
Manufacture and layer properties
The layers are deposited using reactive PVD processes, cathodic vacuum arc evaporation and magnetron sputtering .
Essential layer properties are listed below for the Al66Ti34N layer system:
- Micro-hardness in the range from approx. 2600 to 3300 - phase stability up to 850 ° C, then conversion into the two-phase system AlN + TiN.
- An approx. 300 ° C higher oxidation resistance compared to TiN with approx. 800 ° C.
- Lower electrical conductivity and therefore also thermal conductivity than TiN.
- Typical layer thicknesses: 1 to 7 µm.
In particular, the structural version of the AlTiN layers with a high aluminum content, the AlTiN-Saturn or the HYPERLOX, are widely used worldwide in the coating of high-speed steel or hard metal .
In recent years, the proportion of thicker layers based on Ti50Al50N has increased steadily. The currently (2011) firmly deposited layer thicknesses on cutting tools, whereby here in particular indexable inserts with previously applied edge rounding are to be mentioned, are up to 12 µm.
TiAlN layers are partially doped with at least one of the elements chromium, carbon , silicon (Si), boron , oxygen and yttrium in order to improve certain properties in a targeted manner, which can be advantageous in certain applications. Furthermore, these layers are used for multi-layer systems, e.g. B. used in conjunction with TiSi X N layers. An example of this is the Mpower family of layers from Sulzer Metaplas or HSN² from CemeCon AG. Most of the coating systems are used in various applications, both for wear protection of tools and for the coatings of medical tools as well as for decorative coatings.
Individual evidence
- ^ O. Knotek, T. Leyendecker: On the structure of (Ti, Al) N-PVD coatings. In: Journal of Solid State Chemistry . Volume 70, No. 2, 1987, pp. 318-322, doi : 10.1016 / 0022-4596 (87) 90071-5 .
- ^ J. Vetter: (Alx: Tiy) N coatings deposited by cathodic vacuum arc evaporation. In: Journal of Advanced Materials. Volume 31, No. 2, 1999, pp. 41-47.
- ^ Vetter J .: Vacuum arc coatings for tools: potential and application . In: Surface and Coatings Technology . 76-77, Part 2, 1995, pp. 719-724 , doi : 10.1016 / 0257-8972 (95) 02499-9 .
- ↑ Inka Harrand: PVD layers “ thickly applied”. In: Facts. No. 36, 2011, p. 3 ( PDF ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. ).
