Surface Structuring of a/b-SiAlON Ceramics by Plasma-Etching
*a, S. Holzer a, R. Oberacker a, M.J. Hoffmann a, C. Ziebert b
for Ceramics in Mechanical Engineering, University of
76131 Karlsruhe, Germany
for Materials Research I, Forschungszentrum Karlsruhe
Germany : email@example.com
The plasma-etching technique with a reactive gas is a common practice to investigate the microstructure of Si3N4. In this case the b-grains show a greater etching rate than the grain boundary glassy phase, so that they are preferentially dissolved and the microstructure is revealed.
In this study it was tried to transfer this effect to sialon ceramics but with the aim to create a height-relief in the surface with the function of micro lubrication pockets for the application in lubricated gliding systems.
During this study the effects of plasma etching on sialon ceramics by CF4/O2 were investigated. It was shown that b-grains exhibit a higher etching rate than the grain boundary glassy phase or the a-grains, generating pockets in a range of few µm. According to this, the bearing ratio of such a surface can be adjusted by the relation of quantity of a/b-sialon and the depth of the lubrication pockets by etching parameters like in this case the dwell time.
Therefore sialon samples with different a/b-ratio were produced and subsequently etched under different conditions.
The so created surfaces were characterized by
A FM analysis. Certain selected
compositions and etching conditions have been applied
on samples which were investigated in tribological measurements in self-mated