Uniaxial hot-pressing in bellows containers

The fabrication of dense SYNROC from a low density powder precursor can be carried out routinely by using a new modification of uniaxial hot pressing. Stainless-steel containers with a bellows configuration are used to contain the precursor powder. After heating to a uniform temperature of 1050-11500C a single uniaxial load (up to 20 MPa) is applied, causing the bellows to collapse uniformly. No external die or confining pressure is required. A ''pancake'' of fully dense SYNROC ceramic, completely encased by the collapsed bellows, is fabricated during this hot-pressing operation. Numerous 10-cm-diameter SYNROC pancakes have been produced in this manner. The same configuration has been used to compact zircaloy cladding hull fragments into dense metal monoliths. The process has been successfully scaled up to produce 31-kg pancakes of SYNROC, 37 cm in diameter