High‐purity stoichiometric Si3N4 ceramics through trimethylsilyl‐substituted polysilazanes

Abstract Trimethylsilyl‐substituted polysilazanes were designed and successfully synthesized. They were used to fabricate high‐purity stoichiometric Si 3 N 4 ceramics through pyrolysis process. Trimethylsilyl groups improved the stability of polysilazanes and easily escaped during pyrolysis, which effectively reduced oxygen and carbon content in the final polymer‐derived Si 3 N 4 . The C content of Si 3 N 4 ceramic was below 0.06 wt%, and the O content was below 1.2 wt%. The Si 3 N 4 ceramics remained amorphous up to 1400°C, yet they were completely transformed into α‐Si 3 N 4 at 1500°C. Synergistic effect from low oxygen and carbon content contributed to highly stable amorphous state of Si 3 N 4 till high temperatures. This amorphous Si 3 N 4 ceramics could be used in cutting‐edge technology where high purity is compulsory.