METHOD OF FABRICATING HOT PRESSED SILICON NITRIDE BILLETS

摘要

A method is disclosed of making a plurality of dimensionally accurate hot pressed ceramic bodies. A plurality of Si3N4 billets, having a thickness to width ratio of 1:3 to 1:40 are stacked in a hot pressing assembly (40-41-42-43). The billets are arranged in groups of progressively decreasing number so that (a) for a billet group (10-11-12-13-14) residing in a zone of compression (15) that will experience the least movement along the pressing direction, the stacked number of billets is greatest within such group, and (b) for a billet group residing in a zone of compression (22) that will experience the most movement along the pressure direction, the stacked number of billets (21) within such group is the lowest, each group being separated from adjacent groups by an inert rigid spacer.