1988 Fiscal Year Final Research Report Summary
Effects of Thermal History on the Nucleation in Silicate Melts
| Project/Area Number |
61470052
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
鉱物学(含岩石・鉱床学)
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| Research Institution | Kyushu University |
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Principal Investigator |
AOKI Yoshikazu Faculty of Science, Kyushu University, 理学部, 助教授 (00037277)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIDA Kiyotaka College of General Education, Kyushu University, 教養部, 助手 (60108602)
UEHARA Seiichiro Faculty of Science, Kyushu University, 理学部, 助手 (70158773)
NAKAMUTA Yoshihiro Faculty of Science, Kyushu University, 理学部, 助手 (80128058)
FUKUOKA Masato Faculty of Science, Kyushu University, 理学部, 助手 (70117232)
MOTOMURA Yoshinobu Faculty of Science, Kyushu University, 理学部, 助手 (20037237)
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| Project Period (FY) |
1986 – 1988
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| Keywords | diopside / anorthite / NMR / trimethylsilylation / metastable phase / silicate anion |
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| Research Abstract |
1. ^<29>Si MASS NMR spectroscopy of glasses with diopside composition indicates that all Si are tetrahedrally coordinated to oxygen. Estimates of the average Si-O bond length and average Si-O-Si bond angle determined from empirical correlations of ^<29>Si chemical shift with bond length and angle indicate that these parameters are 1.63^゜_ and 130゜C respectively.
2. The improved trimethylsilylation method reveals that poly-silicate anions present along with a small amount of monomer, dimer, and three-chain in diopside glass.
3. The crystallization kinetics of quenched and annealed glasses with diopside composition were investigated by DTA. X-ray diffretion confirmed that diopside and mixture of diopside and Mg-wollastonite crystallized from quenched and annealed glasses, respectively. The effective activation energy of crystallization of quenched and annealed glasses was derived from DTA curves obtained at various heating rates.
4. The kinetics of crystal nucleation in anorthite melt have been betermined over the range of supercooling between 250゜and 625゜C. Two metastable phases, P2_1 and C2, first nucleate heterogeneously at supercoolings of from 270゜ to 620゜C, depending on the duration. both phases are suddenly transformed to the stable phase, l1^^-, at supercoolings of from 350゜ to 450゜C after the duration of 100 min.
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Research Products
(2 results)
