Characterization and Oxidation Behaviour of Al2O3 Coating Deposited on Ti-Al-Nb Alloy in Air and in 9%O2 + 0.2%HCl + 0.08%SO2 + N2 Atmosphere

• Main Author: Małecka Joanna
• Format: Article
• Language: English
• Published: De Gruyter 2015-02-01
• Series: High Temperature Materials and Processes
• Subjects: oxidation behaviour; coatings; intermetallics; 81.15.cd; 81.65.mq
• Online Access: https://doi.org/10.1515/htmp-2013-0112

The paper presents research results of isothermal oxidation of Ti-46Al-7Nb-0.7Cr-0.1Si-0.1Ni intermetallic alloy with Al2O3 coating. Oxidation was carried out in air and in the atmosphere with the content 9%O2 + 0.2%HCl + 0.08%SO2 + N2 at 750 °C. Mass changes of the specimens were recorded after 50, 100, 300 and 500 hours. The surface morphology of the oxidized samples were studied using Scanning Electron Microscopy (SEM), Wavelength Dispersive Spectroscopy (WDS) and Energy Dispersive Spectroscopy (EDS). The results obtained showed that the corrosion resistance of the examined alloy is better in air. The oxidation in the atmosphere of 9%O2 + 0.2%HCl + 0.08%SO2 + N2 causes the formation of eruptions of Al2O3 and TiO2 mixture, however, in air the forming oxide layer is suppressed by the deposited protective Al2O3 coating.