Proceedings of SerbiaTrib '13

It has already been mentioned that t four factors,each at three levels, have been selected to conductthe abrasiontest. Table 3 indicates the said factor –level combinations and corresponding specific wearrate data which is obtained fromthe followingformula [11]:mW sFL,where, W s = specific wear rate (mmm 3 /Nm)Δm = mass loss recorded gravimetricallyy(gm)ρ = specific gravity of EPDM (gm/cm 3 )F = the normalload on the job (N)and, L = overall sliding distance(m)The worn surface morphology had been studiedfor each sample immediately after the abrasionusing a scanning electron microscope (SEM: JEOL,JSM-6360, model 75 82) to see thesmallest detailof the pattern abrasion in the range of 4 – 5 nm (4 –5 millionths of a millimeter). Thetest had beenconducted immediately after the experiment, thoughit is reported by Pandey et.al. [14] that in theirexperimentsfracture mode did not change withinn 72hours of storage before conducting SEM studiess andcoating etc. The worn surfaces had been coated witha very thinlayer of palladium (Pd) using ionsputtering machine (Auto Fine Coater: JEOL, JFC-to1600) prior to SEM studies. It is not out of placemention here that ioncoating is done on non-etc.)conducting specimen (like biological specimento be analyzed in SEM for quick and highlyefficient results. This is done mainly to preventcharging ofelectrons atthe sample[15]. For somesamples energy dispersive X-ray spectroscopy(EDAX) had also beendone in conjunction withSEM to find out thepercentages of differentelements inthe sample. Elemental mapping withEDAX is helpful to get insight into the chemicalchanges onthe surface and sub-surface of thesample[16].As no chemical reactionis taking placein the present case hence EDAX hass not done for allthe specimens.Figure 6 shows some typical pattern abrasion ofEPDM as obtained fromSEM studies. In figure 6(b)a chunk of rubber agglomerate hass been separatedleaving behind a groove (chunkingand grooving).Figure 6(c) reveals the ridge formation whichsupports theconcept ofrubber wear by the processof plowing.(a)(b)(c)Figure 6. Worn W surface morphology of EPDMcorrespondingg to trial no.1 (×200), 2 (×1000) and 6(×2000) as obtained from SEM studies.The graph of o the average specific wear rate isshown in Figuree 7.13 th International Conference on Tribology – Serbiatrib’133777