TRIBOLOGICAL PROPERTIES OF TRANSITION-METAL CARBOSULFIDES AND CARBOSULFIDE-METAL COMPOSITES

Because of their layered structure featuring a sulfur atom double laye r bound by van der Waals forces, tantalum and niobium carbosulfides we re proposed as solid lubricants. Carbosulfides with high homogeneity a nd controlled purity have been prepared by combustion synthesis. By me ans of a two-line tribometer, the tribological properties of bulk Ta2S 2C, (Ta,Nb)(2)S2C and several intercalation compounds of Ta2S2C were i nvestigated and their performance compared with conventional solid lub ricants. Tantalum carbosulfide showed friction coefficients around 0.1 2, whereas the intercalation compounds and tantalum-niobium carbosulfi de showed higher values, but lower wear rates. For the preparation of Ta2S2C-metal composites, a copper/tin alloy was chosen. The tribologic al performance of such a composite is discussed and compared with a co pper/tin-tungsten, disulfide composite. (C) 1998 Elsevier Science S.A.