Y-Si-Al-O-N system

Redington Keely W, Redington M, Hampshire S (2000) Liquid Formation in the Y-Si-Al-O-N System. In Hampshire S, Pomeroy MJ (eds) Nitrides and Oxinitrides. Mater Sci Forum 325-326. Trans Tech Publications Ltd, Switzerland, p 237... 

Many studies of crystallisation of oxynitride glasses have concentrated on the Y-Si-Al-O-N system. Thompson (1989) outlined the various crystalline phases that exist in this system as shown in the Janecke prism in Fig. 21.2. 

This phase is one of the best examples of a nitrogen glass ceramic, and is also the best documented as regards composition and structure. It occurs at compositions of the type Ln3Si3Al30i2N2, and even though it has been prepared in the Y—Si—Al—O—N system, it is much more readily prepared in rare earth systems of low atomic number (typically La, Ce, and Nd). The structure is well established [59] Figure 5.23 shows the... 

Figure 7. Janecke s triangular prism for the Y-Si-Al-O-N system showing all known phases [24]...

Fig. 8. Outline representation of the Y-Si-Al-O-N system. Glass-forming region within the yttrium-sialon triangular prism on cooling from 1700°C (Drew et al. 1981).

Crystallisation to form composites in the Ln-Si-O-N and Ln-Si-Al-O-N systems has been reported. The disilicate, metasilicate, N-apatite and N-wollastonite phases found in the Y-Si-O-N system (see Fig. 21.2) also exist in the Ln-Si-O-N systems (Leng-Ward and Lewis, 1990 Mandal etal., 1992a Sun etal., 1995 Liddell et al., 1998). 

Loehman reported on the formation of oxynitride glasses in the system Y-Si-Al-O-N. The silica-rich glasses contained up to 7% nitrogen. The changes in thermal expansion coefficient and the glass transition temperature are tabulated below. 

The extent of the glass forming regions in various M-Si-Al-O-N systems (M = Mg, Y, Ca, etc.) has been studied previously and represented using the Janecke prism with compositions... 

In order to obtain a single phase disilicate, partial substitution of Y by a rare earth ion such as La in the Y-Si-Al-O-N glass can be made so that the average ionic radius of the mixed modifier system is compatible with obtaining a single disilicate polymorph. 

The first paper on the fabrication and characterisation of carbon fibre-reinforced glass matrix composites was published in 1969 [1], Major developments in these composite systems were carried out during the 70s and 80s, especially in USA, England and Germany [2,29,30,32,46], There are still considerable research efforts worldwide in this area [6,43, 47-54], A recent development is the use of nitride glass matrices, for example Y-Si-Al-O-N glass [42],... 

Y-Si-Al-O-N has been studied the most extensively of the a-sialon systems (Huang et al. 1983, Stutz et al. 1986, Slasor and Thompson 1987). In this case 0.33 < 1 (Y)... 

Later, it was realized that oxynitride glasses, which revealed themselves to be more resistant to high temperatures than the corresponding non-nitrided glasses, were of interest in their own right. Various systems, in particular the Y-Si-Al-O-N quinary system, were extensively investigated with the preparation and study of properties of a wide variety of bulk glass compositions. 

Si3N4-Si02-AlN-Al203-YN-Y203 system determined by Naik and Tien [J] and Sun et al. [4]. Sixty-eight compatibility tetrahedrons in the Si-Al-Y-N-O system have been established by these authors. 

Fig. 22. Subsolidus phase relations in the Si,Al,Y/N, O system showing a series of compatibility tetrahedrons formed by a -sialon, j3 -SiA ON, and AIN polytypoids [34].

G. Petzow, L. J. Gauckler, T. Y. Tien, and S. Boskovic, b-Si3N4 solid solutions formation by reaction sintering in the system Si, Al/N, O. In Factors in Densification and Sintering of Oxide and Non-Oxide Ceramics (S. Somiya and S. Saito, eds.), pp. 28-39. Gakujutsu Bunken Fukyu-Kai, Tokyo, 1979. 

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