MODIFICATION OF THE MECHANICAL SURFACE-PROPERTIES AND TRIBOCHEMISTRY OF STRUCTURAL CERAMICS BY ION-BEAM TECHNIQUES

The main problems for broader application of fine ceramics are the hig h cost for production and finishing, the sensitivity to fracture and a n unsatisfactory tribological behaviour. Additionally, in recent years , environmental considerations played an increasing role in the discus sion concerning the performance of wear partners in tribological syste ms using environmentally friendly lubricants. To meet these future dem ands, either the system temperatures will have to be lowered or novel surface-modified materials will have to be developed for use in tribol ogically sensitive regions of machines. Ion beam techniques can contri bute to the improvement in the properties of the near-surface region o f these materials. In this work, implantation of titanium and argon io ns in polycrystalline Si3N4 is shown to have a considerable influence on the flexural strength, friction, wear and hardness of ceramics whic h can be applied as automotive and other engineering components. Polyc rystalline Si3N4 samples in rolling contact exhibited after titanium i mplantation a 10-50 times lower wear rate under unlubricated condition s, even under high loads.