The binding of antiwear additives to iron surfaces: quantum chemical calculations and tribological tests

The molecular orbital parameters of lubrication additives and iron atom cluster were calculated by use of a quantum chemical method. The interaction pattern between the additive and metal atom cluster was discussed base on the approximate rule of orbital energy. By comparing some parameters that characterize the action strength between additive and metal, the correlations between the additive molecular structures and additive action abilities with metal are elementally obtained, which may be used as the basis for forecasting the tribological performances of additives. The prediction results obtained by quantum chemical calculations are in good accordance with the results of tribological tests. The molecular orbital parameters exhibit advantages for studying the quantitative structure–activity and structure–property relationships of lubrication additives.