Influence of load and speed on tribological performance of Cu nanofluids in EHL line contacts

Abstract

Nowadays, wear is the leading cause of common machine failure and significant use of lubricants is required to reduce such failure. Lubricants over the years have evolved from animal fats to mineral oils and now nanofluids. Nanofluids are the blend of nanoparticles and base lubricating oil. Copper nanofluids are used as efficient nanolubricants for contacting surfaces because of their high thermal and electrical conductivity. In this paper, influences of applied load and rotational speed on tribological performance of copper nanofluids have been investigated. The effect of viscoelasticity in terms of contact pressure and film thickness in elastohydrodynamic lubrication (EHL) has been also investigated. Experimental tests were performed on multispecimen tribometer machine in pin on roller (line contact) arrangement, using EN31-EN31, EN31-GM, EN31-PB, EN31-Al alloy as tribopairs. Results indicate that both contact pressure and film thickness do not have any significant effect after incorporation of viscoelastic effect in EHL line contacts of copper nanofluids. Coefficient of friction (CoF) for all the tribopairs have been increased with the applied load, with rotational speed for EN31-GM, EN31- Al alloy. However, for EN31-EN31, EN31-PB CoF decreases. Wear has been also shown to be increase with the increase of applied load and rotational speed