MOULD PARTS OF SILICON NITRIDE AND METHOD FOR PRODUCING SUCHMOULD PARTS

摘要

The present invention relates to silicon nitride mould parts, particularly crucibles for use in connection with directional solidification and pulling of silicon single crystals. The mould parts consist of Si3N4 having a total ope n porosity between 40 and 60% by volume and where more than 50% of the pores i n the surface of the mould parts have a size which is larger than the means si ze of the Si3N4 particles. The invention further relates to a method for producing the silicon nitride mould parts.