Process for preparing silicon, aluminium and magnesium nitrides and oxynitrides with a fibrous morphology based on vermiculite

摘要

Process for preparing silicon, aluminium and magnesium nitrides and oxynitrides with a fibrous morphology based on vermiculite. The subject-matter of the invention is a process for the preparation of a ceramic raw material. In this process the organic molecule of acrylonitrile is intercalated with a phyllosilicate (vermiculite) into which n-butylammonium chloride has previously been intercalated. The intercalated monomer can polymerize between the layers of the phyllosilicate in order to produce a mineral-butyl ammonia polyacrylonitrile phyllosilicate complex. Once the polymer has entered the interlaminar space this precursor is subjected to carbothermic reduction in a flow of nitrogen, producing a ceramic raw material containing silicon, aluminium and magnesium nitrides and oxynitrides (B-sialon, B-silicon nitride, and silicon and magnesium nitride) having a fibrous morphology. The products obtained by the method according to the invention have applications as starting materials for the synthesis of advanced ceramic materials with high thermal and mechanical performance.