Janecke prism

Fig. 9. The Janecke prism Si3N4-4(AlN)-4(YN)-2(Y203)-2(Al203)-3(Si02) with the ass plane (schematic)...

The extent of the glass-forming regions in various M-SiAlON systems (M = Mg, Y, Ca, Nd, etc.) has been studied (Hampshire etal., 1985) and represented using the Janecke prism, with compositions expressed in equivalents instead of atoms or gram-atoms. Thus, equivalent percentage (e/o) of cation M is given by ... 

Figure 21.1 shows the glass-forming region in the Y-Si-Al-O-N Janecke prism (Drew et al., 1981). The region is seen to expand initially as nitrogen is introduced and then diminishes above approximately 10 e/o N until the solubility limit for nitrogen is exceeded. 

Glass-forming region in the Y-Si-AI-O-N Janecke prism on cooling from 1700°C (after Drew ef a/., 1981). 

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. 

Y-Si-AI-O-N Janecke prism showing crystalline phases and solid solution ranges. 

Figure 11.25 Janecke prism (hexanary system Si3N4-Al203-Si02-AlN-YN-Y203) to visualize major crystalline phases (empty circles) and minor accessory phases (full circles). On the shaded plane Si2N20-Y40s-...

That is, the amounts of B and C are referred to a constant amount of A. It should be remembered that in the triangular diagram a line parallel to one of the sides indicates, at a given temperature, a constant amount of the component represented by the opposite corner of the triangle and hence, points in plane parallel to one face of a right prism, will indicate, for different temperatures, variation in the amounts of two components, but constancy in the amount of the third. See also Janecke, Z. anorgan, Ckem. 1906, 51, 132. 

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

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