Synthesis and Oxidation Behavior of MAX Phase based Coatings by Magnetron Sputtering for High-Temperature Applications

Kurzfassung

MAX phases exhibit a unique nanolaminate structure that combines the beneficial properties of ceramics and metals making them promising candidates for high-temperature applications. In this study, Ti2AlC, and Ti2AlN MAX phase coatings were synthesized using direct current (DC) magnetron sputtering and reactive sputtering techniques. Ti2AlC coatings were produced using three pure elemental targets (Ti, Al, and C), while Ti2AlN was deposited using Ti and Al targets with nitrogen as a reactive gas. All coatings exhibited X-ray amorphous, dense columnar structures post-deposition. Analytical techniques such as GDOES, EDS, and XRD were employed to refine composition, and high-temperature XRD was used to study crystallization and phase stability under vacuum and laboratory air atmosphere. Oxidation behavior was evaluated on inert substrates and high temperature lightweight materials such as γ-TiAl and SiC at two temperature regimes: 800 °C and 1200 °C. The formation of a protective α-Al2O3 oxide layer, critical for oxidation resistance, was observed. Ti2AlC demonstrated superior stability, with minimal interdiffusion and strong coating adhesion on γ-TiAl substrates. The Ti2AlN MAX phase coating on SiC, showed the formation of a protective α-Al2O3 layer, but degradation due to the interdiffusion of Si and C from the substrate into the coating. By applying an interlayer of AlN the interdiffusion could be prohibited.