PREPARATION OF ULTRALOW-FRICTION SURFACE-FILMS ON VANADIUM DIBORIDE

In this paper, we present a simple annealing procedure (which we refer to as 'flash annealing' because of its short duration) that results i n the formation of an ultralow-friction surface film on vanadium dibor ide (VB2) surfaces. This annealing is performed in a box furnace at 80 0 degrees C for a period of 5 min. During annealing, the exposed surfa ce of the VB2 undergoes oxidation and forms a layer of boron oxide (B2 O3). In open air, the B2O3 layer reacts spontaneously with moisture an d forms a boric acid (H3BO3) film. The friction coefficient of a 440C steel pin against this H3BO3 film is approximately 0.05, compared with 0.8 against the as-received VB2. Based on Raman spectroscopy and elec tron microscopy studies, we elucidate the ultralow-friction mechanism of the Bash-annealed VB2 surfaces. (C) 1997 Elsevier Science S.A.