Friction coefficient of diamond under conditions compatible with microelectromechanical systems applications

Abstract

Because of its good tribological properties, diamond has been suggested to solve the known reliability issues in silicon MEMS components submitted to frictional contacts. An evaluation of self-mating diamond friction under a low load, representative of a number of MEMS applications, was undertaken. Results have shown that initial friction coefficients of 0.02–0.05 can be achieved, as reported in the literature. However, continuation of the test for an extended period of time invariably led to a strong increase of the friction coefficient. This phenomenon has been observed with different types of diamonds (mono-, micro-, or nano-crystalline), suggesting that it is a general behavior for diamond under our experimental conditions. A micro structuration of the surface prevented this phenomenon by limiting the increase of the contact area resulting from wear.