Tribological properties of laser-cladded Fe-based amorphous composite coatings under dry and lubricated sliding

Abstract

Fe-based amorphous composite coatings are promising surface coating materials, because of their low cost, high hardness, and superior wear resistance. In the present study, Fe-based composite coatings with various amorphous contents (35.9–59.3%) were deposited onto 1045 steel via laser cladding, and the influence of laser-cladding parameters on the amorphous content was analysed. The cross sections of the coating layer and ground coating surface were then characterised in terms of the microstructure, phase composition, amorphous content, grain size, and microhardness. Importantly, the tribological properties of coatings with various amorphous contents under both dry and lubricated sliding conditions with light and heavy loads were systematically investigated. The microstructure of the crystalline/amorphous mixture was found to be a function of the temperature gradient, cooling rate, and chemical composition. The high microhardness was related to the amorphous content and grain size. The tribological properties were found to be insensitive to the amorphous content under both dry and lubricated conditions under light and heavy loads. The manifold morphologies of the wear tracks and the transition of the wear mechanism were the result of the combined effects of the amorphous content, phase composition, and size and distribution of the crystalline phase.