Glass-Forming Region

1 shows the glass-forming region of the GeS2-Sb2S3-PbS system. 

Glass forming region Very stable glass region Sub stable glass region 

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Vassilev V, Tomova K, Parvanova V (2009) The glass-forming region in the system GeSe2-PbSe-PbTe. Mater Chem Phys 114 874-878... 

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). 

Figure 2.13 The glass-forming region in relation to the phase diagram for the system Pb0-V205 (After Rawson, 1956).

Figure 6.22. (a) Glass forming region in the system Li2S-P2S5-Lil. (b) Influence of composition (mole% Lil) on the conduetivity (After Malugani et al., 1983). 

Figure 6.23. Glass forming region in the ternary system Li2S (Lil)2 B2S3. ( ) transparent glasses, (o) opaque glasses. (After, Burckhardt et al., 1984)...

Figure 6.28. Glass forming region and iso-Tg ( C) curves for the system Li20 AI2O3 Nb20s (o) glassy, ( ) crystalline (After Tatsumisago, 1985)...

Fig. ). Glass forming regions of (a) ZrE j-BaF LaPj system (Lucas 1987) and (b) ZnF2-Cdp2-BaF2 system (Matecki et al. 1982b).

The observed relationship between the average heats of atomization and the physical properties of vitreous materials is obviously very useful in designing new materials with the desired plgrsical properties within the glass-forming region of a system. 

The elastic constants and Tg for glassy GeSc2 can be calculated by extrapolating their concentration dependences in the glass-forming region of the Se-Ge system to the composition GeSc2. The concentration dependences of the elastic constants and Tg for systems in which the aforementioned compounds are formed were considered in [1,2, 8] and need not be discussed here. 

A composition such as Ln2Si2A104N3 is dose to the limit of Al-substitution in the melilite structure, and in the low-Z rare earth systems. This composition is also close to the limit of nitrogen substitution in the liquid (and hence glass-forming) region in these systems. 

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