Preparation of Si/C/Al/N ceramics by pyrolysis of polyaluminasilazanes

✍ Scribed by Bruno Boury; Dietmar Seyferth

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 107 KB
• Volume: 13
• Category: Article
• ISSN: 0268-2605
• DOI: 10.1002/(sici)1099-0739(199906)13:6<431::aid-aoc856>3.0.co;2-r

✦ Synopsis

Polyaluminasilazanes were prepared quantitatively by reaction of oligosilazanes (RSi(H)NH) n (R = Me, Et) with various amounts of either trimethylaluminum, (CH 3 ) 3 Al, or dimethylaluminum amide, (CH 3 ) 2 AlNH 2 . The products were characterized by 1 H, 29 Si and 27 Al NMR and IR spectroscopy. Alkylation of the Si-H groups was observed when trimethylaluminum was used. Their pyrolysis was carried out under argon or ammonia. Ceramic residues were obtained in high yield and were characterized by elemental analysis and X-ray powder diffraction. Formation of mixed ceramics containing silicon nitride, silicon carbide and/or aluminum nitride was observed depending on the precursor and the experimental procedure that was used. The thermal decomposition of the polyaluminasilazane between 50 and 700 °C was investigated by IR analysis of the gas evolved during the pyrolysis. Molecular aluminasilazanes were studied as model compounds.