On the Coexistence of Chemically Similar Stable and Metastable Phases in the BeO–MgO–Al2O3–SiO2 System
- Resource Type
- Original Paper
- Authors
- Mikhailov, M. A.; Mamontova, S. G.; Zelentcov, S. Z.; Demina, T. V.; Belozerova, O. Yu.; Bogdanova, L. A.
- Source
- Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques. 12(4):756-760
- Subject
- beryllian indialite
phase with β-quartz structure
khmaralite
spinel
silicate melt
phase portrait
metastable phases
X-ray amorphous phases
sol–gel precursor
- Language
- English
- ISSN
- 1027-4510
1819-7094
The joint crystallization of the stable phase (a number of solid solutions of chromium-containing beryllian indialite) and metastable phases (crystalline modifications) of the compound with β-quartz structure (Si0.64Al0.28Mg0.21Be0.09)IVO2 ~ Mg1.89Be0.81Al2.52Si5.76O18 admixed with Cr2O3 phases of khmaralite Mg1.21Cr0.01Be0.46Al1.78Si3.38O20 and spinel {(Mg0.95Be0.045Si0.005)IV(Al1.31Cr0.67Mg0.02)VI}O4 is performed using melted chromium–beryllian indialite preliminarily obtained by solid-phase synthesis as a precursor. Simultaneously, the residual X-ray amorphous melt of composition Mg1.83Cr0.01Be1.04Al2.64Si5.57O18 is hardened. Thus, a reconstructive transition from the beryllian indialite melt to a phase with the β-quartz structure is implemented, and the chemical similarity of these compounds is demonstrated. The rate of change in the crystallization isotherm of 2°С/h and increased heat outflow through the highly heat-conducting walls of the Pt–Rh crucible (taper) contribute to this process.