Structural and micromechanical properties of ion-beam mixed tungsten-on-steel system

Structural and micromechanical properties of ion-beam mixed tungsten layers were studied. 45 nm thick W layers deposited on HSS substrates were Kr-ion -beam mixed at temperatures ranging from room temperature (RT) up to 450 de greesC. The samples mixed at RT are amorphous. Increase of the process temp erature results in the formation of crystalline layers. Amorphous layers ar e characterized by low friction coefficient and relatively low hardness. Cr ystallization of layers results in an increase of hardness and friction coe fficient. Wear rates of ion-beam mixed layers are always lower when compare d with the untreated steel substrates. The results are discussed based on a model assuming the presence of a thin, soft layer on a hard substrate. (C) 2001 Elsevier Science Ltd. All rights reserved.