Osumilite

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. 

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

Property Ba-osumilite matrix Ba-stuffed cordierite matrix... 

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

Goldman, D. S. Rossman, G. R. (1978) The site distribution of iron and anomalous biaxiality in osumilite. Amer. Mineral., 63,490-8. 

Zeolites do not represent an easily definable group of crystalline aluminosilicates. There are obvious borderline cases like some sodalite-type species which have been included in this survey. On the other hand, nepheline hydrate, the scapolites, osumilite (12), and buddingtonite, an ammonium feldspar with zeolitic water (17), have not been considered here. 

Barium Osumilite. A glass-ceramic formulation BaMg2Al3(Si9Al303o) patented by J. J. Brennan et al (U.S. Pat 4589900,1986, used as the foundation material for composites. 

OstwaM Ripening. Grain growth due to differential dissolution between particles of different sizes and shapes. Solute dissolves at sharp corners, or from small particles, and tends to reprecipitate on coarser, larger or rounder particles, which grow at the expense of fine particles. Osumilite - see barium osumilite. Outside Vapour - phase Oxidation (MCVD, OVPO and VAD). See optical fibres. 

It must be noted, however, that other crystal phases apart from the P-quartz solid solution are also involved in the crystal phase formation of primary crystal phases up to a-cordierite. These crystal phases render the solid-state reaction highly complex. Hence, several unknown crystal phases with flat, almost two-dimensional habits were observed and could not be identified as Mg-petalite or osumilite as shown by Schreyer and Schairer (1961). 

Schreyer W. and Schairer J.F., "Metastable Osumilite-and Petalite-Type Phases in the System Mg0-Al203-Si02, Am, Min., 47, 90-104 (1962). 

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