| Popis: |
Some new methods of prepearing ceramic precursors - polycarbosilanes (PCS), having alternate silicon and carbon atoms in main skeleton, as well as modified PCS with hetero-atoms (B, Ti, Zr, Fe, Co, Ni, Cr) have been developed. Therewith into the main polymer chain links are introduced, containing metal-oxygen bonds, fragments of dicarbollylic, metal cenous and other complex compounds. Obtained products differ by alloying additives content, softening temperature, molecular mass, solubility, mouldability, cross-linking (oxidizability) and thermochemical treatment conditions. For increasing of structure uniformity and consequently ceramic phase density during PCS thermochemical treatment optimum selection of alloying components and their distribution in polymer molecules were studied. Synthesized products have been tested in the field of high temperature strength materials creation including coreless SiC fibres, reactive-sintered ceramics, SiC/SiC fibrous composits. Obtained polymers are tested as impregnating additives for porous materials, protective coatings and ultradispersed SiC powders. |
