Composite ceramic materials for applications in engineering at high temperature and under severe conditions of thermal shock and a process for their production.

摘要

Ceramic composite materials for ingineering applications at high temperature and under severe conditions of thermal shock and a process for their production. The formulated and granulated composite material of the invention is prepared and thus composed of an appropriate mixture formed by an Si3N4 matrix (80-95% by weight), BN (3-15%) and sintering additives, TiB2, Y2O3, Al2O3 and ZrSiO4 (10-20%). This formulated mixture, which is shaped by conventional ceramic techniques, gives rise, by sintering, via an optimized thermal cycle in three steps located between 1,300 and 1,400 DEG C between 1,500 and 1,700 DEG C, and between 1,750 and 1,825 DEG C, to ceramic parts which as a whole combine high strength at room temperature with high resistance to thermal shock and high toughness and are suitable for applications in engineering at high temperature and under severe conditions of thermal shock.