Cordierite matrix composites

Table 3.16 Properties of Ba-osumilite and Ba-stuffed cordierite matrix composites containing 30 wt% No. 1 whiskers10...

Variation of properties of Ba-stuffed cordierite matrix composite with temperature (reproduced by permission of Am. Ceram. Soc. Bull.) . 

C. Kaya, F. Kaya, A. R. Boccaccini, Fabrication of Stainless-Steel Fibre-Reinforced Cordierite Matrix Composites of Tubular Shape Using Electrophoretic Deposition, J. Am. Ceram. Soc. 85, 2575-2577 (2002). 

Cordierite glass, matrix for ceramic-matrix composites, 5 553t... 

The first composite system is a barium osumilite composition reinforced with 30 wt% (25 vol%) No. 1 whiskers. The second composite system evaluated is a barium-stuffed cordierite matrix 30 wt% No. 1 whisker composite. The room-temperature properties of these two composites are given in Table 3.16. 

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... 

The cordierite and spinel matrix composites both showed strength improvements over the monolithics that were retained up to 1000°C. Measurements on the spinel matrix composite showed a significant decrease at 1200°C. 

Table 2.5 Summary of elevated temperature mechanical properties for zirconia, cordierite, and spinel matrix composites...

Honeycomb monoliths are obtained by extruding a paste made by catalytic material, whereas plate catalysts are made by depositing the catalytic material onto a stainless steel net or a perforated metal plate. Composite ceramic monolith catalysts, consisting of a monolith matrix made of cordierite coated with metal oxide SCR material, are also offered. However, they may suffer adhesion problems in the presence of dust and their use may be preferably limited to clean environment. Coated metal monoliths are constructed of thin metal foil and are characterized by large cell densities. In view of this, they are used exclusively in dust-free applications. 

---