Abstract: A biocompatible prosthetic device comprising a metal alloy substrate, an intermediate layer of a high-temperature polymer which is strongly bonded thereto, and an exterior coating of dense vapor-deposited carbon. The carbon layer is thromboresistant and strongly adheres to the intermediate layer which in turn strongly adheres to the metal alloy. The polymer may be the reaction product of pyromelletic dianhydride and a diaminodiphenyl ether, and the carbon may be deposited under high vacuum conditions from a suitably heated carbon source, e.g., by ion-plating or vacuum vapor deposition.