Polysilazanes, processes for their preparation, ceramic materials which contain silicon nitride and can be prepared from them, and preparation thereof

摘要

The invention relates to novel polysilazanes, their preparation, their further processing to ceramic material containing silicon nitride and this material itself. To prepare the polysilazanes, Si,Si'-diorganyl-N-alkyl-tetrachloro-disilazanes of the formula RSiCl2-NR'-SiCl2R are reacted with ammonia. The polysilazanes can then be pyrolyzed to ceramic material containing silicon nitride. The polysilazanes according to the invention dissolve in the customary aprotic solvents.