ROLE OF REINFORCING CERAMIC PARTICLES IN THE WEAR BEHAVIOR OF POLYMER-BASED MODEL COMPOSITES

The role of the ceramic particles in the wear behaviour of particulate composites was investigated by minimizing the influence of the often intricate metallic matrix (high speed steel, Al alloys, Mg alloys, ...). For this, the metallic matrix was replaced by a soft and homogeneous polymer matrix showing a very low wear resistance. Polymer-based model composites were thus obtained. Their dry sliding wear behaviour was studied by means of a pin-on-disc apparatus which measured friction and wear coefficients. A number of experiments were performed using different ceramic particle types (Al2O3, TiC, SiC, ...) and varying the particle size (5-100 mu m) and particle volume fraction (5, 10, 20, 30, 40%). An alumina counterbody was used since conventional steel was not suitable for studying the wear of the ceramics due to high abrasion. Interrupted wear testing was also carried out to study the wear mechanisms using scanning electron microscopy (SEM) observation of the wear tracks and cross-sections. A crack formation and particle detachment mechanism was identified for the unreinforced polymer material. The addition of ceramic particles decreased the wear coefficient up to 50 times. Large particles (of about 100 mu m) were found to protect the polymer matrix better than small particles (of about 20 mu m). Particle volume fraction higher than 20% did not increase significantly the wear resistance of the composites. Results were in keeping with those obtained using metal matrix composites containing similar ceramic particle additions.