MOULD PARTS OF SILICON NITRIDE AND METHOD FOR PRODUCING SUCH MOULD 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 open porosity between 40 and 60% by volume and where more than 50% of the pores in the surface of the mould parts have a size which is larger than the means size of the Si₃N₄ particles. The invention further relates to a method for producing the silicon nitride mould parts.