Oxidation-resistant Ti–90Al coatings with lotus effect surface morphology deposited on a γ-TiAl alloy

Ti–90Al (in at.%) coatings were deposited on Ti–45Al–8Nb alloy at two different temperatures, 300 and 540 °C. The coating sputtered at 300 °C consisted of Al and TiAl3 with columnar grain structure. The morphology, chemical composition and microstructure of the coating sputtered at 540 °C were strongly dependent on the substrate microstructure. The two coating variants formed oxidation-resistant Al2O3 scales during oxidation. The special morphological features of the coatings make them interesting for geometrically structuring the surfaces to provoke the lotus effect.