Transition Metal Ions and Heterogeneous Nucleation in Glass. Technical Report No. 2. A Magnetic Study of the Catalysed Crystallisation of a CaO-MgO-Al2O3-SiO2 Glass Using Fe2O3.
Abstract
Magnetization measurements have been made on (mole %) 28.9 CaO14.3 MgO-11.4 Al2O3-40.4 SiO2 glass containing 5 mole % Fe2O3 from 300 K to 50 mK. Electron paramagnetic resonance measurements were also made on these specimens at 300K. A qualitative elucidation of the mechanism of catalyzed crystallization has been obtained namely (1) that clusters of Fe ions already exist in quenched glass (2) on nucleation at lower temperatures the clusters clump together with little evidence of crystallinity (3) on nucleation at higher temperatures the clusters clump together with evidence of crystallinity (4) the Fe(2+)/Fe(3+) ratio decreases with increasing nucleation temperature, and this oxidation state probably sets the crystalline phase observed after crystallization (5) on crystallization, Fe3O4 or gamma Fe2O3 or MgFeAlO4 form, depending upon the temperature of nucleation (6) the catalyzed crystallization of the major phase is apparently by the epitaxial growth around small crystallites of the above magnetic phases.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1975
- Accession Number
- ADA006636
Entities
People
- Deug W. Moon
- Joseph C. Williams
- Kyung J. Kim
- Robert K. Maccrone
Organizations
- Rensselaer Polytechnic Institute