S. Friedle, N. Laska, R. Braun, H.-E. Zschau, M.C. Galetz, M. Schütze
The oxidation behaviour of a novel thermal barrier coating (TBC) system on a β-stabilized TiAl alloy was investigated at 900 °C in air containing water vapour and sulphur dioxide. This recently developed system consists of a 7 wt.% yttria partially stabilized zirconia topcoat deposited on fluorine-treated and pre-oxidized TNM-B1 substrate material. During thermal cycling at 900 °C in atmospheres containing either 10 vol.% H2O or 0.5 vol.% SO2, no spallation of the TBCs was observed for exposure periods exceeding 1000 cycles of 1 h dwell time. Fluorinated samples without TBCs showed similar oxidation behaviour, whereas the untreated TNM-B1 alloy revealed significant oxidation.