New coating materials for artificial heart valves

Amorphous hydrogenated silicon carbide films (a-SiC:H) prepared by plasma-activated chemical vapor deposition (PACVD) were experimentally evaluated. Depending on the ratio of silicon to carbon, bandgap energies up to 2.3 eV and dark conductivities between 10^-9 and 10^-8 (Ω cm)^-1 at 37°C were obtained. Doping with phosphorus led to an increase in conductivity up to 10^-3 (Ω-cm)^-1. Additionally, the deposited layers showed a microhardness of 10 GPa or more, which results in a high wear resistance. These findings demonstrate that a-SiC:H films with a silicon content of about 80% do match the electronic as well as the mechanical requirements for improved hemocompatibility in contrast to carbons