Incoloy 909 superalloy was treated at 950°C to form coatings of different chemical composition by thermochemical diffusion. Packing of the samples in reactive powders lead to the formation of iron borides (Fe 2 B and FeB) together with nickel boride, NiB, and nickel silicide, Ni 2 Si, on the surface of the alloy depending on the exposure time. X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy analyses suggest that growth of the coatings is controlled by diffusion of reactive species into the metal structure. Microabrasion wear resistance of the coated specimens was studied at 1 N load for a fixed sliding speed of 0.11 m s −1 and it was compared against uncoated samples of the alloy. It was found that coating the alloy for 12 and 20 h increased the hardness of the alloy and therefore its wear resistance.