On-line and post-mortem wear measurement of static counterpart in a ball-on-disk test

Abstract

this paper presents an experimental evaluation of friction coefficient and wear of WC binderlessceramics. The tests were conducted at room temperature and atmospheric conditions according to theASTM G99-95a standard. Silicon carbide (SiC) balls were used as static counterpart. The tests wereperformed at a rotating sliding speed of 0.3 m/s and an initial mean Hertzian contact pressure of 1.9 GPa.The disk specimens were surface finished by grinding. On-line monitoring and post-mortem analysis withtwo independent techniques, i.e., surface profilometry and optical microscopy, were used to elucidate thetribological characteristics of the studied material. Results of the post-mortem measurements werecompared to a geometrical wear model for calculation of the volume of the worn cap of the ball. Thiscalculation appeared to be in good agreement with the on-line wear monitoring. The first 100 m of slidingwas identified as running-in period. Beyond a sliding distance of 100 m a steady stage in penetration depthwas reached, while a higher fluctuation in friction coefficient was observed, which could be attributed to theinteraction with wear particles and simultaneous formation and delamination of debris layer, polishing andabrasion.