Abstract
At high pressures or at low temperatures lubricating oils cause the solidification First, phase diagrams of paraffinic mineral oils (PN), traction oils (SN), polybutene (PB), DOS and BBPH were drawn in pressure-temperature plots of three different states (liquid, viscoelastic solid and elastic-plastic solid). Next, the four-ball tests were used to evaluate anti-wear characteristics of lubricating oils in boundary lubrication regime. The SNs showed the minimum wear scar in four-ball wear test The anti-wear characteristics of oils was closely related with EHL film thickness and the oil molecular packing parameter T_<VE>-T (T_<VE> : viscoelastic solid transition temperature at pressure p of wear test condition, T: oil temperature).
