Tribological testing of peroxide-cured EPDM rubbers with different carbon black contents under dry sliding conditions against steel

The friction and sliding wear behaviors of peroxide-cured ethylene/propylene/diene rubbers (EPDM) were studied against steel counterparts under dry conditions. The carbon black (CB; N347 type) content of the EPDM rubbers was varied between 0 and 60 parts per hundred parts rubber (phr). For their tribotesting, different test configurations, viz. pin(steel)-on-plate(rubber) (POP) and roller(steel)-on-plate(rubber) (ROP), were used and their oscillation wear behavior (fretting) studied, too. The EPDM rubbers were characterized using dynamic-mechanical thermal analysis (DMTA), hardness, tensile and tear tests. The coefficient of friction (COF), volume loss and specific wear rate of the EPDM rubbers were determined. It was found that with increasing CB content all above characteristics were reduced. However, the COF and wear parameters strongly depended on the related test configuration. The wear mechanisms were concluded by inspecting the worn surfaces in scanning electron microscope (SEM) and discussed.