Wear and friction properties of high speed steel covered with Al. Si, Mo an
d W and ion-beam mixed were studied using a reciprocating ball-on-flat trib
otester. In all studied cases the reduction of wear and friction coefficien
ts were obtained. The tungsten layers were the most effective allowing 3-ti
mes friction and 5-times wear reduction. The analysis of the wear tracks co
mposition changes points to the decrease of wear induced oxidation as an im
portant factor leading to the improved mechanical propel ties of the mixed
layers. (C) 1999 Elsevier Science B.V. All rights reserved.