FRICTION BETWEEN DIAMOND SURFACES IN THE PRESENCE OF SMALL 3RD-BODY MOLECULES

Molecular dynamics simulations have been used to examine the friction between the hydrogen-terminated (111) faces of diamond with small hydr ocarbon (third-body) molecules trapped between them. In general, the p resence of the trapped third-body molecules reduced the friction betwe en the diamond surfaces with the most pronounced reduction at high loa ds. The size and shape of the third-body molecule, as well as the alig nment of atoms on opposing diamond surfaces, were found to be paramoun t in determining the magnitude of the friction. These results are comp ared to results from previous simulations that examined the effects of chemically bound hydrocarbons on the friction between diamond surface s and to available experimental data.