Mechanical and tribological properties of aluminide coating modified with yttrium

Recent studies demonstrate that an oxygen-active element such as yttrium is beneficial to the wear resistance of aluminide coating in corrosive environments. In this research, mechanical properties of different characteristic layers or domains of an aluminide coating modified with yttrium were investigated using a micro-mechanical probe. Effects of yttrium on the wear behavior of the layers in air and in corrosive media were investigated, using a scratch tester. Wear and corrosive wear of the aluminide coating were also evaluated using a pin-on-disk tribometer. Composition of the coating was analyzed using energy-dispersive spectroscopy (EDS). The results showed that the oxygen-active element significantly improved the mechanical properties of the aluminide coating and its resistance to wear in both dry and corrosive environments. A dark layer with very high hardness and wear resistance was observed in the Y-containing aluminide coating. The hardness of this dark layer was close to that of WC (tungsten carbide), while its elastic behavior was superior to that of WC.