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H. Asanuma, P. Polcik, S. Kolozsvári, F. Klimashin, H. Riedl, P.H. Mayrhofer:
"Improved mechanical properties and thermal stability of Ti-Al-N through alloying with La-borides";
Talk: 45th International Conference on Metallurgical Coatings and Thin Films 2018, San Diego, CA; 2018-04-23 - 2018-04-27; in: "Book of Abstracts 45th ICMCTF 2018", (2018), 9.

After discovering the positive effect of Al on many properties (such as oxidation resistance) of Ti-N in 1986, Ti-Al-N hard coatings quickly conquered the market for protective coatings . The progress made in research provides a wealth of variations, such as alloyed Ti-Al-N. Just recently we showed the enormous improvement in deposition rate, mechanical strength, and thermal stability of Ti-Al-N when using Ce-alloyed Ti-Al- composite targets. Here, we further follow this concept by studying coatings, developed by sputtering a 2% LaB6 alloyed Ti0.50Al0.50 composite target in a mixed Ar/+N2 atmosphere.
We achieved a dramatic increase in film growth rate from 4.8 to 8.4 μm/h when sputtering a Ti0.49Al0.49(LaB6)0.02 instead of a Ti0.50Al0.50 target, while keeping all other deposition parameters unchanged. Due to the different poisoning behavior of TiN and AlN, we observed an increase of the Al-fractions (x in the range of 0.56-0.58) within our coatings (Ti0.42Al0.58N and Ti0.42Al0.56La0.02 -B-N, respectively) (Ti/Al ratios of 0.72 and 0.75 for the pure and alloyed coating, respectively) compared to the target compositions. Furthermore, the hardness increased from 34 to 40 GPa, the maximum annealing temperature (before a significant hardness reduction sets in) increased from 800 to 1100 °C, and also the oxidation resistance was significantly improved. After exposure to ambient air at 950 °C for 1 h the oxide scale thickness is only ... 0.50 µm on our Ti0.42Al0.56La0.02 -B-N coatings, whereas the Ti0.42Al0.58N coatings were already fully oxidized. The results obtained even outperform the already excellent properties of Ce-alloyed Ti-Al-N.
Based on our results we can conclude, that the addition of 2% LaB6 to Ti0.5Al0.5 composite targets, not only leads to coatings with significantly improved mechanical properties and thermal stability, but also boosts the deposition rate.