Friction and wear properties of zirconium diboride in sliding against WC ball

Friction and wear properties of the hot pressed zirconium diboride were investigated at different loads and frequencies under reciprocative sliding, using a counter body of tungsten carbide (WC-Co) ball. Coefficient of friction, wear volume and specific wear rate were evaluated. Wear mechanism have been analysed by using optical microscopy and SEM-EDS techniques. Coefficient of friction (COF) for monolithic zirconium diboride under dry reciprocative linear sliding wear with WC-Co ball was evaluated between 0.8 and 0.4 at different loads and frequencies. Load enhancement was found to decrease the COF of ZrB2 with WC ball. An increase in load from 5 N to 20 N decreased the COF from 0.84 to 0.52 at 10 Hz frequency. Increase in sliding frequency also resulted in decrease in COF. It is decreased from 0.52 to 0.43 by increasing frequency from 10 Hz to 15 Hz at 20 N. Specific wear rate of zirconium diboride were evaluated in the order of 10(-5) mm(3)/N.m. Tribo chemical layer formation was observed on the worn surface of zirconium diboride (flat) along with shallow abrasive grooves.