Oxidation protection of C/C–SiC composites by an electrophoretically deposited mullite precursor: Cyclic thermogravimetric analysis

• Published in: Journal of the European Ceramic Society 2007, Vol.27 (2), p.1299-1302
• Main Authors: Damjanović, T., Argirusis, Chr, Jokanović, B., Borchardt, G., Moritz, K., Müller, E., Herbig, R., Weiss, R.
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Cermets, ceramic and refractory composites; Chemical industry and chemicals; Composites; Cross-disciplinary physics: materials science; rheology; Electrophoretic deposition; Exact sciences and technology; Materials science; Mullite; Other materials; Physics; Sol–Gel Synthesis; Specific materials; Structural ceramics; Technical ceramics
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2006.04.026

Sufficiently thick and homogeneous layers which transform into mullite at T ≥ 1000 °C were synthesized by means of sol–gel technology and electrophoretically deposited onto the surface of C/C–Si–SiC composites. The protectiveness of the deposited mullite layers was isothermally tested in air in the temperature range 1200 ≤ T ≤ 1550 °C for up to 200 h. At temperatures above 1600 °C, the protectiveness of the deposited layer is reduced due to the existence of a liquid phase and the formation of CO bubbles above the cracks in the SiC layer. In order to prolong the protectiveness of our mullite layers at higher temperatures an additional layer from a suspension of mullite precursor with 5 wt.% of Al 2O 3 powder was deposited. The protectiveness of the obtained mullite and mullite/Al 2O 3 multilayer systems were also tested under cyclic conditions. These experiments yielded encouraging results, which will have to be confirmed at higher temperatures.