The friction which occurs when two diamond (111) hydrogen-terminated surfaces are placed in sliding contact is investigated for sliding in different crystallographic directions, as a function of applied load, temperature, and sliding velocity. We find a directional dependence to the friction coefficient, μ; that for certain crystallographic sliding directions μ increases with increasing load and as the temperature decreases; and that for the sliding speeds investigated here, μ is approximately independent of sliding velocity. We also found that the sliding velocity may become a factor for very slow, experimentally achievable sliding velocities when sliding in the [112¯] direction but not for sliding in the [11¯0] direction.

• Received 6 August 1992

DOI:https://doi.org/10.1103/PhysRevB.46.9700