US Patent 7402541 Silicon nitride compositions

The present invention provides silicon nitride with tungsten carbide additives in a sinterable material comprising silicon nitride and tungsten carbide, in which the silicon nitride content is a minimum of about 80% and wherein the total nitride component is about 28-40 w/w % N2, and further comprising about 1.5-3.5 w/w % Al, about 2-6 w/w % Y, about 1.5-7 w/w % W, and about 3-9 w/w % O2. which after sintering will produce ceramic bodies with a high degree of toughness suitable for armor applications.