Thermal oxidation treatment of B2 iron aluminide for improved wear resistance

A surface modification technique, namely thermal oxidation (TO) treatment has been developed to improve the tribological properties of B2 iron aluminide. The composition, the microstructure and the mechanical properties, e.g. hardness and elastic modulus of the surface treated layers have been characterised using a number of analytical techniques including XRD, SEM, AFM and microindentation and nanoindentation. Tribological properties of the surface treated and untreated samples were evaluated using a pin-on-disc tribometer with WC/Co ball as counterpart. It has been found that a hard and dense oxide layer can be produced on the iron aluminide surface by the thermal oxidation treatment, which reduces the coefficient of friction and wear volume loss of the iron aluminide. Based on the experimental results and analysis, the wear mechanisms for both untreated and thermal oxidation treated iron aluminide are discussed.