PRODUIT A PARTICULES ORIENTEES

摘要

Fabricating a sintered product comprises: (a) preparing a slip comprising a set of ceramic particles suspended in a liquid phase; (b) optionally casting the slip in a mold and/or removing air bubbles present in the slip; (c) oriented freezing the slip to form a block of frozen slip and to form crystals of a solidified liquid phase separated by walls; (d) optionally demolding the block to obtain a macroporous preform; (e) removing the crystals of liquid phase of the block; (f) optionally debinding the preform; and (g) optionally sintering the preform to obtain the sintered product. Fabricating a sintered product comprises: (a) preparing a slip comprising a set of ceramic particles suspended in a liquid phase; (b) optionally casting the slip in a mold and/or removing air bubbles present in the slip; (c) oriented freezing the slip by movement of a solidification front at a speed, which is less than a speed of encapsulation of the ceramic particles, to form a block of frozen slip and to form crystals of a solidified liquid phase separated by walls having an average thickness that is = 1 of an average thickness of orientable ceramic particles (104); (d) optionally demolding the block by sublimation to obtain a macroporous preform; (e) removing the crystals of solidified liquid phase of the block; (f) optionally debinding the macroporous preform; (g) optionally sintering the macroporous preform to obtain a sintered product; and (h) optionally machining and/or impregnating the sintered product. The amount of set of ceramic particles is more than 4 vol.% and less than 50 vol.%. The set of ceramic particles comprises: a first particulate fraction constituted of orientable particles, preferably anisotropic particles having a median length, where the amount of ceramic particles is more than 1 vol.%; and a second particulate fraction having a median length, which is ten times less than the median length of the anisotropic particles, where the amount of ceramic particles is more than 5 vol.%. The amount of first and second particulate fractions is more than 80 vol.%. The ceramic particles are totally or partially replaced by equivalent amounts of precursors. An independent claim is included for the sintered product comprising macroscopic frustoconical tubular pores that extend parallel to each other in a longitudinal direction, where each pore is defined by walls comprising 50 vol.% of orientable ceramic particles and the walls between the pores comprise 5 vol.% of particles.