Wear and electrochemical behaviour of Mg–Al intermetallic coating

Abstract

An erbium modified Mg₁₇Al₁₂ based coating was fabricated by hot press sintering on as extruded AZ61 Mg alloy. The Er modified coating was composed of Mg₁₇Al₁₂ and Al₃Er phases. As a result of the presence of the dispersed Al₃Er phase, the coating had a greater microhardness than Mg₁₇Al₁₂. Thermal effects of sintering at 400°C for 1 h caused no obvious deterioration in the wear resistance of the AZ61 Mg matrix. Electrochemical and wear resistance tests showed that the Er modified Mg₁₇Al₁₂ based coating had a lower corrosion current density and a lower friction coefficient than Mg₁₇Al₁₂, the AZ61 Mg matrix and a thermal diffusion coating (TDC). The superior wear resistance of the sintered coating resulted from the hard Al₃Er phase. The corrosion resistance of the sintered coating was better than that of the TDC as a result of suppression of hydrogen evolution by the rare earth metal Er.

Keywords:

• Intermetallics
• Microstructure
• Corrosion
• Sintering

Acknowledgements

The authors gratefully acknowledge the National Natural Science Foundation of China (grant nos. 51374151, 51001079, 21201129 and 51208333) and the Postgraduate Innovation Program of Shanxi Province (grant no. 20113028) for supporting this work.