Supercritical fluctuations in the B2O3PbOAl2O3 system
1971; Elsevier BV; Volume: 5; Issue: 5 Linguagem: Inglês
10.1016/0022-3093(71)90042-1
ISSN1873-4812
Autores Tópico(s)High-pressure geophysics and materials
ResumoA small-angle X-ray diffraction study of the supercritical region of the B2O3PbOAl2O3 immiscibility surface is presented. This is the first time that diffraction methods have been applied to the study of critical opalescence in a system of oxides at high temperatures. Debye's theory is shown to be applicable and, from the spectra correlation lengths and the range of molecular interactions l is calculated. The topography of the supercritical region is determined and the relationship between l and the main interatomic distances in the melt discussed. The spectra of supercritical fluctuations in the liquid are compared to the spectra of vitreous specimens obtained by quench. This permits the quality of the quench to be assessed and an accurate determination made of the initial condition for the study of spinodal decomposition in the miscibility gap.
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