Hans-Joachim Scheibe

Deposition of superhard amorphous carbon films by pulsed arc sources

Hydrogen-free amorphous carbon films with hardness comparable to crystalline superhard materials have been deposited by special pulsed arc techniques. With the combination of very high hardness, high smoothness, and low adhesion activity to other materials which are in contact with them, these films show superior behavior in wear and slide applications. The influence of plasma and deposition conditions on these film properties and the choice of optimum conditions are discussed.

Nanostructured Carbon Films

By periodic variation of the deposition conditions nanometer multilayers of amorphous carbon films of varying density are deposited. Such carbon-carbon multilayers can be used for the preparation of X-ray mirrors of extreme irradiation stability and the optimization of tribological carbon coatings. Combining these techniques with concepts demonstrated in the preparation of fullerenes and nanotubes leads to graphitic films of very high hardness. Potential applications involve such different fields as field emission cathodes for flat panel displays and low-friction wear-protecting films.

Large area deposition of superhard films

During the 1990s, the Laser-Arc technology for the deposition of superhard amorphous carbon films (Diamor®) was developed at the Fraunhofer Institute for Material and Beam Technology. This technology has now been scaled up by a factor of 4 compared to existing devices and integrated in an industrial large-volume vacuum arc coater. Initial results demonstrate the possibility of depositing well adherent Diamor® films with a thickness of more than 2 microns and a hardness above 4000 HV on larger parts and tools. This opens up a wide field of industrial applications.