Synergistic effect of Pt and Hf on the early-stage oxidation behaviour of NiAl coating at 1000 °C

The initial-stage oxidation behaviours of unmodified, Pt and Pt + Hf modified NiAl coating are systematically investigated by employing the photo-stimulated luminescence spectroscopy (PSLS) and transmission electron microscopy (TEM) technique. Both Pt and Hf additions can retard the B- to a- Al2O3 2 O 3 phase transformation. The oxidation rates of the modified NiAl coatings are initially higher than that of the unmodified NiAl coating due to the longer presence of B-Al2O3. 2 O 3 . However, they decrease drastically when the oxide in the scale turns to be a-Al2O3 2 O 3 dominantly. The delayed phase transformation in the modified coatings results in lower residual stress within the oxide scale. (c) 2022 The Author(s). Published by Elsevier B.V. on behalf of Institute of Metal Research, Chinese Academy of Sciences. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )