Si/B/C/N/Al precursor-derived ceramics: Synthesis, high temperature behaviour and oxidation resistance

• Published in: Journal of the European Ceramic Society Vol. 24; no. 12; pp. 3409 - 3417
• Main Authors: Müller, A., Gerstel, P., Butchereit, E., Nickel, K.G., Aldinger, F.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 2004; Elsevier
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Chemical industry and chemicals; Exact sciences and technology; Miscellaneous; Oxidation; Precursor-derived ceramics; Precursors-organic; Si–B–C–N–Al; Synthesis; Technical ceramics; Oxidation; Precursor-derived ceramics; Precursors-organic; Synthesis; Si–B–C–N–Al; Hydrogen; Thermogravimetry; Organometallic compound; Organic polymers; Nitrogen; Experimental study; Carbon; X ray diffraction; Precursor; Thermal stability; Boron; Oxidation stability; Chemical preparation; Multiple system; Technical ceramics; Silicon; Manufacturing; Raman spectrum
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2003.10.018

The Si/B/C/N/H polymer T2(1), [B(C 2H 4Si(CH 3)NH) 3] n , was reacted with different amounts of H 3Al·NMe 3 to produce three organometallic precursors for Si/B/C/N/Al ceramics. These precursors were transformed into ceramic materials by thermolysis at 1400 °C. The ceramic yield varied from 63% for the Al-poor polymer (3.6 wt.% Al) to 71% for the Al-rich precursor (9.2 wt.% Al). The as-thermolysed ceramics contained nano-sized SiC crystals. Heat treatment at 1800 °C led to the formation of a microstructure composed of crystalline SiC, Si 3N 4, AlN(+SiC) and a BNC x phase. At 2000 °C, nitrogen-containing phases (partly) decomposed in a nitrogen or argon atmosphere. The high temperature stability was not clearly related to the aluminium concentration within the samples. The oxidation behaviour was analysed at 1100, 1300, and 1500 °C. The addition of aluminium significantly improved the oxide scale quality with respect to adhesion, cracking and bubble formation compared to Al-free Si(/B)/C/N ceramics. Scale growth rates on Si/B/C/N/Al ceramics at 1500 °C were comparable with CVD–SiC and CVD–Si 3N 4, which makes these materials promising candidates for high-temperature applications in oxidizing environments.