Formation kinetics of multi-layered interfacial zone between γ-TiAl and glass–ceramic coatings via interfacial reactions at 1000 °C

• An interfacial glass/Ti5Si3/α-Al2O3/Ti3Al layers was formed after oxidation.
• The Ti5Si3 and α-Al2O3 thickened parabolically with time.
• The Ti3Al layer thickened first and then thinned during oxidation.
• The glass–ceramic coating showed good high temperature protection for γ-TiAl.

Glass–ceramic coatings are investigated for high temperature protection of γ-TiAl. This investigation focuses on the interfacial reactions between γ-TiAl and a glass–ceramic coating at 1000 °C in air by means of transmission/scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. A thin interfacial zone of multilayered glass/Ti5Si3/α-Al2O3/Ti3Al at the interface was observed after oxidation for several hours. Both the growth of Ti5Si3 and α-Al2O3 layers obeyed parabolic rules, while the thickness of the Ti3Al layer increased first and then decreased. The mechanism for formation kinetics of the interfacial zone was discussed.