Composites mullite matrix

T. N. Tiegs, P. F. Becher, and P. Angelini, Microstructures and Properties of SiC Whisker-Reinforced Mullite Composites, in Mullite and Mullite Matrix Composites, Ceramic Transactions, Vol. 6, eds. S. Somiya, R. F. Davis, and J. A. Pask, American Ceramic Society, Westerville, OH, 1990, pp. 463-472. 

A.T. Hunt, CCVD Processing of Lanthanum Phosphate and Beta-Alumina Fiber Coatings for Mullite Matrix Composites, Contract DM19561712, NSF SBIR Phase 1 Grant, 1996. 

Domier of Germany developed oxide fiber-reinforced mullite matrix composite systems in the 1980s. The system was based on SMs Nextel 312 fibers and slurry impregnation of a mullite matrix. This composite demonstrated modest levels of strength (120 MPa [17.4 ksi]) and low failure strain (0.2 to 0.3 percent). Several hot gas exhaust nozzles for Dormer s turboprop airerafl were successfully deployed and continue to be used in regular service. 

DAVID WILSON is a research specialist with 3M and has more than 10 years of research and development experience in the synthesis of new ceramic fibers using sol-gel techniques and is the inventor of the Nextel 610 and Nextel 720 ceramic fibers. His experience includes the development of novel fiber precursor formulations, continuous fiber processing, and characterization of ceramic fibers at room and elevated temperatures. Current research activities include preceramic polymer-derived SiC fibers and MOCVD coating and composite fabrication for the Mullite Matrix Composite Consortium Program. Mr. Wilson holds four patents and is the author of several publications. 

C. Kaya, E. G. Butler, A. Selcuk, A. R. Boccaccini, and M. H. Lewis, Mullite (Nextel 720) fibre-reinforced mullite matrix composites exhibiting favourable thermomechancial properties, J. Eur. Ceram. Soc., 22 2333-2342 (2002). 

Y. Hirata, S. Matsushita, Y. Ishihara, H. Katsuki, Colloidal processing and mechanical properties of whisker-reinforced mullite matrix composites, 7. Am. Ceram. Soc. 74 2438-2442(1991). 

H. Schneider, M. Schmiicker, J. Goring, B. Kanka, J. She, P. Mechnich, Porous alumino silicate fiber/mullite matrix composites Fabrication and properties, in Innovative Processing and Synthesis of Ceramics, Glasses, and Composites IV (N. P. Bansal and J. P. Singh, Editors), Ceram. Trans. 115,415-434 (2000), Am. Ceram. Soc., Westerville, OH. 

Mullite and Mullite Matrix Composites, vol. 68 (eds R.F. Davies and JA. Pask), American Ceramic Society, Ohio. 

SOM 90] SOMIYA S. (ed.), Mullite and mullite matrix composites , Ceram. Trans. 6, The... 

Kanka, B and Schneider, H., "Aluminosilicate fiber/mullite matrix composites with favorable high-temperature properties." Journal of the European Ceramic SocietylO.S (2000) 619-623. 

Ha. J.S. and Chawla, K.K. (1993). Effect of SiC/BN double coating on fiber pullout on mullite fiber/ mullitc matrix composites. J. Mater. Sci. Lett. 12, 84-86. 

Most structural PMCs consist of a relatively soft matrix, such as a thermosetting plastic of polyester, phenolic, or epoxy, sometimes referred to as resin-matrix composites. Some typical polymers used as matrices in PMCs are listed in Table 1.28. The list of metals used in MMCs is much shorter. Aluminum, magnesium, titanium, and iron- and nickel-based alloys are the most common (see Table 1.29). These metals are typically utilized due to their combination of low density and good mechanical properties. Matrix materials for CMCs generally fall into fonr categories glass ceramics like lithium aluminosilicate oxide ceramics like aluminnm oxide (alnmina) and mullite nitride ceramics such as silicon nitride and carbide ceramics such as silicon carbide. 

Whereas the ambient mechanical properties have been studied extensively, the high temperature properties of mullite and mullite/zirconia matrix composites have been examined by only a few studies.18 30,32 34... 

As mentioned previously, the main body of research on whisker-reinforced composites was concerned with alumina, mullite, and silicon nitride matrix materials. None the less, selected work examined zirconia, cordierite, and spinel as matrix materials.16-18 The high temperature strength behavior reported for these composites is summarized in Table 2.5. As shown, the zirconia matrix composites exhibited decreases in room temperature strength with the addition of SiC whiskers. However, the retained strength at 1000°C, was significantly improved for the whisker composites over the monolithic. Claussen and co-workers attributed this behavior to loss of transformation toughening at elevated temperatures for the zirconia monolith, whereas the whisker-reinforcement contribution did not decrease at the higher temperature.17,18... 

FIGURE 12.12 Examples of FGM CMCs (left) the combination of NLM Nicalon SiC fiber reinforced zirconia (in white) and mullite (in black) matrices (right) a Nasicon matrix reinforced with mullite (Nextel) and SiC (NLMTM) fibers (see the sketch). (Reprinted from Colomban, R, Process for fabricating a ceramic matrix composite incorporating woven fibers and materials with different compositions and properties in the same composite, Mater. TechnoL, 10, 89, 1995. With permission.)... 

FIGURE 12.17 Spectral in-line scan (2 pm step) of a composite cross section. Spectra were recorded from one NLM202 fiber to another, through the aluminosilicate + (Zr02 Ge02) tailored interface and the mullite matrix. (Reprinted from Colomban, R, Raman microspectrometry and imaging of ceramic fibers in CMCs and MMCs, 103, 517, 2000. With permission from The American Ceramic Society.)... 

Mouchon, E., and Colomban, R, Microwave absorbent preparation, mechanical properties and RF/microwave conductivity of SiC (and/or mullite) fibres reinforced NASICON matrix composites, J. Mater. ScL, 31, 323, 1996. 

Colomban, P., Bruneton, E., Lagrange, J.L., Mouchon, E., Sol-gel mullite matrix-SiC and -mullite 2D woven fabrics composites with or without zirconia containing interphase. Elaboration and properties, J. Eur. Ceram. Soc., 16, 301, 1996. 

At the DLR Institute of Materials Research an all-oxide CMC (WHIPOX = wound highly porous oxide) consisting of alumina fibres Nextel 610 or mullite based fibre (Nextel 720, both 3M) and an alumina or mullite matrix, respectively, has been developed in recent years [1,2]. Mullite-based CMCs typically offer higher creep stability than alumina-based composites but display lower thermal conductivity. Lower thermal stability of alumina-based materials, however, can be accepted, since service temperature is significantly lower for these materials as a result of the better cooling efficiency. Therefore material development was focused on alumina... 

E. Mouchon, and P. H, Colomban, Microwave Absorbent Preparation, Mechanical Properties and r. f-microwave Conductivity of SiC (and/or mullite) Fibre Reinforced Nasicon Matrix Composites, J. Mater Sc/., 31(2), 323-334 (1996),... 

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