This research analyzes the methods for producing silicon nitride and the properties of initial powders. The main methods for obtaining materials based on silicon nitride are described. Liquid-phase sintering and hot pressing were used to develop dense materials based on silicon nitride. As a sintering additive, 3 – 10 wt.% and 5 – 20 wt.% of yttrium-aluminum garnet were used for hot-pressed and sintered materials, respectively. The mechanical properties (modulus of elasticity, bending strength, fracture resistance, and Vickers hardness) of sintered and hot-pressed materials have been studied. Maximum properties were obtained with sintered materials containing 15% oxides and hot-pressed materials containing 10% oxides.