PROCESS FOR MANUFACTURING A SINTERED STRUCTURAL CERAMIC PART OF ALUMINUM NITRIDE

摘要

The invention process is comprised of the following steps: a) preparation of a homogeneous mixture of boron nitride BN, aluminum, and a binder in the form of a liquid or paste, which will solidify by means of a chemical reaction and/or the drying of a thinner, the boron nitride and the aluminum being in powder form; b) forming of said mixture by mold casting, followed by pressing and heating at a temperature not higher than approximately 70 DEG C, in order to harden the binder and obtain a sold raw mix which can be handled; c) elimination of the binder by heating at a temperature of about 300 DEG C; d) impregnation of the pores of the raw mix by immersion in a bath of aluminum or aluminum alloy in molten state, separation of the impregnated preform from the bath, and cooling; e) machining of the Al-BN composite preform to obtain the final dimensions of the desired part; f) sintering and reaction at a temperature of between 900 and 1000 DEG C in order to form an aluminum nitride-based ceramic object; g) thermal treatment at a temperature of between 1100 and 1250 DEG C to produce the migration of the residual aluminum from the pores of the part, and the mechanical elimination of the aluminum collected on the surface after possible cooling.