The invention relates to a method for preparing a SiBCN-containing thermally-polymerisable
ceramic precursor. The method comprises the steps of enabling vinyl
dichlorosilane and hexamethyldisilazane, which are in a certain ratio, to react at a certain temperature, adding a certain amount of NaBH4
reducer into the
reaction product for reduction after reaction is complete, then, adding dimethyl vinyl
chlorosilane into the reduced
reaction product to continue reaction, heating up the
reaction product to distill off a
solvent and some unreacted
raw material molecules, finally, adding a
solvent n-
hexane into the reaction product to wash the reaction product, thereby obtaining a colorless
viscous liquid product, i.e., the soluble and fusible SiBCN
ceramic precursor. According to the synthesis method, the operation is simple and convenient, experimental conditions are easily controlled, experimental steps are reduced, the cost is low, the prepared SiBCN
ceramic precursor is soluble and fusible, has good processability, is good in fluidity and can be subjected to thermal
polymerization directly, the yield of the prepared product can reach 60% the input amount of
chlorosilane, and the yield of sintered ceramics can reach 64%.