Silicon nitride-based material, the production and utilization thereof in microwave processes

摘要

The invention relates to a material based on silicon nitride (Si3N4) and characterized in that it contains 0.1 to 40 weight percent free silicon and in that it has a porosity of up to 50 percent by volume. The oxygen and carbon content and the content of other impurities is preferably less than 3 percent by weight. The material may contain secondary crystalline phases such as SiC, TiN, TiCN, TiC, ZrN and/or ZrC. Different production methods of said material are also disclosed. Recycled Si3N4 is preferably used as starting material. The material according to the invention is particularly useful as combustion adjuvant in microwave sintering operations. The free Si content and the utilizability of the material can be restored by effecting a regeneration process.