Chemical analytical instrumentation and advanced surface analysis techniques were combined with X-ray diffraction to investigate the chemistry and the crystal structure of the well-known Ga/In/WSe2self-lubricating compact. The data indicate that the active ingredients within the compact are the lamellar gallium and indium selenides formed during the cure of this material. These solid lubricants work in conjunction with the residual WSe2not yet reduced by the Ga/In during the cure cycle. The binder encapsulant holding the lubricative entities together is the residual Ga/In eutectic, partially reacted to substoichiometric selenides of mostly indium. The high-temperature, tribooxidative resistance of the compact is attributed to a protective mechanism, whereby the substoichiometric indium selenides preferentially oxidize. The oxide network becomes a diffusion shield to the encapsulated, lamellar ingredients. The practical use of the compact is limited by inherent thermodynamic instability problem at elevated temperatures, and the removal of the protective oxide layers by tribological action.Presented at the 39th Annual Meeting in Chicago, Illinois, May 7—10, 1984