Oxidation Behavior of Aluminum Nitride Thin Films on Si and Superalloy Substrates

Abstract

Potential of aluminum nitride (AlN) as an application for thermal barrier coatings (TBCs) is investigated. Oxidation Behavior was examined for AlN thin films deposited by DC sputtering. It is confirmed by annealing at 1000 °C in the air that the surface of the AlN film became γ-alumina. CoNiCrAlY bond-coated Ni based alloy (Alloy738) was used as the substrate for comparison of AlN-coated specimen to non-coated one. The AlN coated surface was effective to keep smooth surface. Transmission electron microscopy observation showed that the AlN was maintained near the interface to the CoNiCrAlY. The result means that thermally grown oxide (TGO) generation form the CoNiCrAlY was suppressed during the oxidization of the AlN, although partial oxidization of the AlN coating proceeded remarkably. This work was entrusted by NEDO as ″Nanostructure Coating Project″.