High reduction of diamond friction by oxygen containing liquids

The influence of the environment on the tribological properties of diamond has been studied by investigating the effect on the friction coefficient of oxygen containing liquids introduced at the interface of contact. A diamon d stylus was allowed to perform reciprocating movement on a diamond surface under different loads and sliding velocities. A droplet of the chosen liqu id was introduced at the interface and the changes in the friction coeffici ent were recorded. All the liquids tested reduced the value of the friction coefficient significantly, by an extent which depended on the chemical com position of the liquid, the load and the sliding velocity. An interpretatio n of our results is given in terms of the reduction of adhesion due to the adsorption of these liquids on the surface, and of the possibility of graph itisation occurring on the surface during sliding. (C) 2000 Elsevier Scienc e S.A. All rights reserved.