FRICTION IN 2-BODY ABRASIVE WEAR OF A WC-CO COMPOSITE BY SIC

Friction was measured for the abrasion of a WC-Co cemented carbide by 120 mu m SiC papers as a function of specimen length in the direction of sliding. The coefficient of friction extrapolates to near 1.0 for z ero length and drops rapidly with specimen length to a steady value of 0.33 for long specimens. The effect is attributed to wear of the abra sives during contact with the hard specimen surface. As the contacting abrasives wear, their average indentations into the surface become in creasingly shallower, and the deformation pattern goes through a serie s of changes from plastic to surface plastic to elastic-plastic and pe rhaps finally to elastic wave. With these changes the friction forces gradually decrease. The length-adjusted friction value for the cemente d carbide extends the friction coefficient-hardness plot described ear lier for metals, single-phase alloys, and hardened and tempered steels . This indicates that there is a continuum of friction-causing events in the abrasion process which stretches across the hardness spectrum. (C) 1997 Elsevier Science S.A.