Microstructural and chemical constitution of the oxide scale formed on a pesting-resistant Mo-Si-Ti alloy

The oxidation behaviour of the pesting-resistant eutectic alloy Mo-20Si-52.8Ti was investigated by addressing microstructural and chemical constitution grazing incidence X-ray diffraction GIXRD atom probe tomography APT oxide scales formed at 800 1200 °C in order to understand their protective character. duplex Si-Ti-oxide scale air, i.e. within so-called “pesting regime”, is considerably slow growing with a thickness (11 ± 3) ?m after 1000 h exposure. It composed Ti(+IV)-oxide composition approximately TiO2.1 confirmed SiO2 islands, which are most likely amorphous. °C, potential application temperature, characterised top single-phase an underlying increased (68 11) total. consists rutile TiO2 some cristobalite as determined GIXRD. analysis Ti-oxide confirms stoichiometry TiO2.2. comprising Ti- Si-oxide strongly off-stoichiometric compounds, namely TiO1.4 SiO1.6. Initial linear growth kinetics found change cubic for exposure times longer than 100 h. At higher temperatures 1100 diffusion-controlled, almost parabolic prevail.