Wear testing of hard coatings: more than wear rate?

The present paper describes how in depth analysis and modelling of wear data obtained from uni- and bidirectional wear tests were used to determine criteria for the selection of materials for tribological applications. Different wear modes in unidirectional ball on disc tests were linked to a load to roughness dependence between body and counterbody. The displacement of the ball is described using a particle flux model and the wear rate in bidirectional fretting tests i.s discussed, including a new concept based on dissipated frictional energy. The merits of the various approaches used to measure wear in tribological systems are also discussed.status: publishe

Proton formation and diffusion in amorphous SiN_x:H

ABSTRACTIn this work the release of atomic hydrogen from SiNx:H films is investigated. Thermal treatment as well as UV-illumination induces the formation of H2, increasing the tensile stress in the film. N-rich SiNx:H films release hydrogen only by UV-illumination, indicating involvement of charge trapping. Ab initio calculations show a possible reaction path for the release and diffusion of protons that also explain the diffusion of hydrogen into Si substrates.</jats:p

High-precision low-damage grinding of polycrystalline SIC

Spherical grinding was conducted with a ductile regime mode using a CNC grinding machine and a metal-bond diamond tool with a grit size of 25 mum. The ductile grinding process generated silicon carbide spherical surfaces with surface roughness o