Shape forming of ceramic powders by manipulating the interparticle pair potential

New forming technologies have been developed for advanced ceramic powders b y manipulating the potential between particles using either the electrostat ic or the steric method. The important aspect in either case is the develop ment of a short-range repulsive potential, which is summed with the pervasi ve attractive van der Waals potential to produce an interparticle pair pote ntial characterized by a well in which particles sit at an equilibrium sepa ration distance. This interparticle potential makes it more difficult to pu sh the particles into contact during consolidation, and it controls the flo w behavior of the consolidated body. Flow stresses in the range of 0.1 MPa impart clay-like behavior and opportunities for pressure forming. Much smal ler flow stresses allow shape forming via Colloidal IsoPressing, where weak ly attractive particles are forced into contact within a rubber mold to pro duce an elastic body that can be removed from the mold without shape distor tion. In these approaches, strength degrading inclusions can be removed pri or to consolidation by passing the powder, formulated as a dispersed slurry , through a filter to produce more reliable ceramic components. (C) 2001 Pu blished by Elsevier Science Ltd.