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Oxidation mechanism of PVD TiAlCrYN coating observed by analytical TEM

ABSTRACT: Multicomponent TiAlCrYN coating has been grown on a titanium alloy Ή METAL 834 by combined cathodic arc etching and unbalanced magnetron sputtering. The coated system outperforms γ-TiAl alloy Ti-48Al-2Cr-Nb by exhibiting linear oxidation after ex­ posure for lOOOh in air at 750°C. Cross-sectional analytical transmission electron microscopy combined with X-ray diffractometry and Raman spectroscopy has given detailed investigation of the nitride-oxide transition. A double-layered nano-polycrystalline oxide scale has been deter­ mined to be alumina-like (Al, Ti)2C>3 on top and rutile-like (Ti, A1)02 in subsurface.