High temperature-stabile silicon boron carbide nitride ceramics comprised of silylalkyl borazines, method for the production thereof, and their use

Silylalkylborazine of formula (X):

• in which R1 each independently denotes hydrogen, halogen, a hydrocarbon residue with 1 to 20 C atoms, N(R′)(R″) or OR′, in which R′ and R″ each independently represent hydrogen or a hydrocarbon residue with 1 to 20 C atoms and R2 and R3 each independently denote hydrogen, halogen, N(R′)(R″) or OR′ in which R′ and R″ each independently represent hydrogen or a hydrocarbon residue with 1 to 20 C atoms and R4 each independently denote hydrogen, halogen, N(R′)(R″) or OR′ in which R′ and R″ each independently represent hydrogen, or a hydrocarbon residue with 1 to 10 C atoms or Sn(R*)3 or Si(R*)3 in which R* each independently denote R2 or a hydrocarbon residue with 1 to 20 C atoms.