Tribological behavior of Al2O3/Al composite coating on γ-TiAl at elevated temperature

• An Al2O3/Al composite coating was prepared on γ-TiAl alloy by magnetron sputtering.
• Al2O3/Al coating exhibits high hardness and excellent elastic modulus.
• Al2O3/Al coating shows lower friction coefficients and wear rates compared to substrate.
• Al2O3 particles may function as the lubrication to reduce friction.
• Al2O3/Al coating improved the wear resistance of γ-TiAl at elevated temperatures.

An Al2O3/Al composite coating was fabricated on the γ-TiAl alloy substrate to improve its friction wear performance at elevated temperature. A series of ball-on-disk type tests, sliding against a Si3N4 counterpart, were carried out at three temperatures: 20, 300 and 500 °C. The wear rates and friction coefficients of Al2O3/Al composite coatings at elevated temperature were much less than those of substrates. The anti-wear behavior of Al2O3/Al composite coating is attributable synergistically to its high hardness, excellent elastic modulus and self-lubrication by Al2O3 particles. This coating may be potential surface enhancement for Ti–Al intermetallics at elevated temperature.

Schematic diagram of the coating evolution during friction wear test.Figure optionsDownload as PowerPoint slide