Effect of high-pressure rheology of lubricating oils on boundary lubrication

High-pressure rheology of lubricating oil was determined using different experiments, and the phase diagram was drawn. The four-ball wear tests were used to evaluate anti-wear characteristics of oils in boundary lubrication condition. The bridged ring compound oils showed the minimum wear scar in the four-ball wear tests. The diameter of wear scar decreases with increasing the elastohydrodynamic film-forming capability. Next, we considered the molecular packing parameter TVE−T at the four-ball wear test. The TVE−T values of bridged ring compound oils were in the range 250–360 and oils were elastic-plastic solid. It is concluded that the solidified oil film under boundary lubrication conditions has the anti-wear action.