Oxidation behaviour of V2AlC MAX phase coatings
Clio Azina, Stanislav Mráz, Grzegorz Greczyński, Marcus Hans, Daniel Primetzhofer, Jochen M. Schneider, Per Eklund
Abstract
We report on the oxidation behaviour of V2AlC coatings up to 800 °C, in air. The coatings were deposited at 580 °C using magnetron sputtering from a powder metallurgical composite V2AlC target and were subsequently oxidised for 5, 15 and 30 min. The microstructural evolution of the samples was investigated, and X-ray diffraction patterns were collected to track the formation of oxides. The first indications of oxidation appear after just 15 min at 500 °C, as V-based oxides grew on the surface of the coatings. Later, the presence of mostly V-based oxides and ternary (V, Al)-oxides was observed starting after 5 min at 600 °C. Further analyses confirmed outward diffusion of V and inward diffusion of O, while Al tends to sublimate. α-Al2O3 was only indexed after 5 min at 800 °C. Ex-situ electrical resistivity measurements allowed tracking the oxidation progress of the V2AlC coating.