Ceramic product with oriented particles and method for the production thereof

Process for manufacturing a product, optionally sintered, said process comprising the following steps:

• a) preparing a slip comprising an ensemble of ceramic particles in suspension in a liquid phase, the ensemble of ceramic particles representing more than 4% and less than 50% of the volume of the slip and comprising:
• a first particulate fraction consisting of orientable, particles having a median length L′50 and representing more than 1% of the ceramic particles, in percentage by volume based on the ensemble of ceramic particles;
• and
• a second particulate fraction having a median length D50 at least ten times less than L′50 and representing more than 1% the ceramic particles in percentage by volume based on the ensemble of ceramic particles;
• the first and second particulate fractions together representing more than 80% of the ensemble of ceramic particles, in percentage by volume,
• (b) optionally, pouring the slip into a mould and/or removing air bubbles contained in the slip,
• (c) oriented freezing of the slip by displacement of a solidification front so as to form a block of frozen slip, the velocity Vp of the solidification front being less than the velocity of encapsulation of the ceramic particles Vc and adjusted so as to form crystals of solidified liquid phase separated by walls with an average thickness “e” greater than or equal to the average thickness of the orientable ceramic particles W150;
• (d) optionally, removing said block from the mould,
• (e) removal of the crystals of solidified liquid phase from said block, optionally removed from the mould so as to obtain a macroporous preform,
• (f) optionally, removal of binder from the macroporous preform obtained at the end of step e),
• (g) optionally, sintering the macroporous preform so as to obtain a sintered product;
• (h) optionally, machining and/or impregnation of said sintered product;
• the ceramic particles being replaceable, partially or completely, with equivalent amounts of precursors that are transformed into ceramic particles so as to obtain, said ensemble of ceramic particles, and/or
• the ceramic particles being replaceable, partially or completely, with equivalent amounts of particles of the same shape of a ceramic precursor that is transformed into ceramic in step f) or g).