NEW DEVELOPMENTS ON Magnetron sputtered HARD AL-CR-OXIDE and related PROTECTIVE thin films

D. Diechle, M. Stüber, H. Leiste, S. Ulrich

Karlsruhe Institute of Technology (KIT), Institute for Materials Research I, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen (Germany)

10 Mai 2010

German Aerospace Center, Institute of Materials Research, Germany

The development of new coatings withstanding high temperatures and mechanical loads is a key factor for significant progress for example in manufacturing or in mechanical engineering.

Aluminum oxide and derivative thin films are promising candidates for such applications. Recently, the physical vapour synthesis of such coatings is attracting large scientific and technical interest. Especially Al-Cr-O and related coatings could offer simultaneously thermal stability, chemical inertness, excellent high temperature toughness and hardness with regard to their mixed ionic and covalent bonds. A combinatorial approach to the development of both Al-Cr-O and related thin films by means of reactive r.f. magnetron sputtering is presented. Detailed results on the thin films composition, microstructure and properties will be presented as a function of the major deposition parameters and the sample position in relation to the Al-Cr target. The study shows that the growth of nano-crystalline, stoichiometric, metastable corundum-like solid-solution (Al_1-x,Cr_x)₂O₃ thin films with a high degree of crystallinity and Vickers hardness up to 2600 HV0.05 is possible at non-equilibrium conditions already at low substrate temperatures of 500°C.