Structural Studies on High Temperature Inorganic Materials
Grant-in-Aid for Overseas Scientific Survey.
|Allocation Type||Single-year Grants|
|Research Institution||Hokkaido University|
YOKOKAWA Toshio Hokkaido University . Professor, 理学部, 教授 (60000783)
MASSIOT D. フランス国立研究機構, 高温物理学研究所(CNRSーCRPHT), 主任研究員
GERVAIS Monique CNRS, CRPHT . Chief Researcher, 高温物理学研究所(CNRSーCRPHT), 主任研究員
GERVAIS F. フランス国立研究機構, 高温物理学研究所(CNRSーCRPHT), 次長
COUTURES J.P フランス国立研究機構, 高温物理学研究所(CNRSーCRPHT), 所長
SHIMOKAWA Shigezou Hokkaido University . Associate Professor, 工学部, 助教授 (70001302)
KAWASAKI Shinji Hokkaido University . Instructor, 理学部, 助手 (40241294)
MAEKAWA Hideki Hokkaido University . Instructor, 理学部, 助手 (60238847)
MASSIOT Dominique CNRS, CRPHT . Chief Researcher
GERVAIS Froncois CNRS, CRPHT . Vice Director
COUTURES Jean-Pierre CNRS, CRPHT . Director
|Project Fiscal Year
Completed(Fiscal Year 1993)
|Keywords||High Temperature Inorgainc Chemistry / High Temperature NMR Spectroscopy / High Temperature IR / VIS Spectroscopy / Molten Oxides / Magma / Glasses / Silicates|
It was aimed at the present study to clarify the atomistic structures of high temperature materials, especially amorphous states including glassy and molten states, with the aids of various experimental methods. The development of apparatus for those studies was also subsidiarily tried. Test of the high temperature probe for NMR which have been developed in the both laboratories was one of the important issues. Here are described the final three themes and their present situations.
1. The local structure around Na^+ ion in sodium bearing silicate melt
^<23>Na NMR spectra in sodium silicate and aluminosilicate were observed up to 1700ﾟC. The composition dependence of ^<23>Na chemical shift was obtained. From the comparison of chemical shifts with that of crystals, number of the nearest order around Na ion was seven.
2. IR/Visible absorption spectroscopy of iron bearing silicate glasses
It was aimed to observe extra absorption than ordinary d-d transition. A couple of preliminary test shows
that at Fe_3O_4 content of as high as 10 mole%, absorption was observed at the visible range.
3. Order-disorder dynamics of Spinel(MgAl_2O_4)
It is known that Mg(at tetrahedral site at the ordered spinel) and Al(at octahedral site) tend to mix at high temperature. In previous works, only the quenched samples have been studied. In the present work, the direct measurement at high temperatures was carried out. The mixing was observed to start at around 700ﾟC. A sharp peak at the position of tetrahedral Al was found above 1400ﾟC implying very rapid chemical exchange.
On the other hand, room temperature MAS-NMR of natural spinels which have been heated for various time intervals and then quenched, made it possible to evaluate the amount of Al at tetrahedral site as a function of the intervals.
It may be worthy of note that in addition to the themes above mentioned, ^<17>O NMR of water containing high temperature-high pressure quenched albeit glass was initiated.
In view of limited research periods, our visit to CNRS (Orleans) was just a initiation and inspiration of our project and future prospects are more important. Counter visit of French group to Japan by French project is highly desirable for that purpose. Less
Research Output (10results)