MANUFACTURING METHOD OF HOMOGENEOUS PREFORMS FOR SINTERED SILICON CARBIDES FROM POWDER WITH WIDE ARTICLE SIZE DISTRIBUTION

摘要

PURPOSE: Provided is a manufacturing method of high density preforms for sintered silicon carbides(SiC) which have no separation of particle sizes and no compaction defects by pressing powder with wide particle size distribution. CONSTITUTION: The preforms with homogeneous compaction are manufactured by the following steps of; (i) mixing SiC powder with wide particle size distribution, 1-20wt.%(based on the powder) of phenol resin, and alcohol(ethyl or butyl alcohol); (ii) dropping the mixed slurry into water or hardener-contained water(70-90deg.C), and mixing strongly for 5-30min to form granules; (iii) filtering and washing; (iv) drying granules at 70deg.C or lower; (v) feeding granules to a mold and pressing under pressure of 0.1-50MPa for 5-60min for homogeneously compacted preforms; and (vi) thermal treating the preforms at 400-1250deg.C in inert gas atmosphere or vacuum, which results in that carbon residue is obtained from decomposition of phenol resin and strength of preforms is increased by densification of carbon residue.