1990 Fiscal Year Final Research Report Summary
Studies on the Change of Physical Properties of Glassy Slags Near Glass Transition. Region.
| Project/Area Number |
63470048
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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 |
金属精錬・金属化学
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| Research Institution | Tohoku University |
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Principal Investigator |
SHIRAISHI Yutaka Tohoku University, Research Inst. of Mineral Dressing and Metallurgy, Prof., 選紘製錬研究所, 教授 (00006024)
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| Co-Investigator(Kenkyū-buntansha) |
OGAWA Hiroshi Tohoku University, Research Inst. of Mineral Dressing and Metallurgy, Assistant, 選紘製錬研究所, 助手 (40194443)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Borosilicate / Oxynitride / Viscosity / Glass Solder / Joining of Ceramics / Devirifying Heat Treatment / MD Simulation |
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| Research Abstract |
In order to apply a glass transition behavior to an estimation of the properties at higher temperatures, the followings were carried out : 1. Viscosity measurement over a wide temperature range, 2. Devitrification of glass solder after joining of cermics by a suitable heat treatment in which the temperatures were determined by glass transition and crystallization temperatures, 3. Molecular dynamic simulation for shear viscosity of molten silicates. Obtained results are summarized as follows :
1. The viscosity of borosilicate and oxynitride systems were measured by a parallel plate viscometer (measuring range 10^<10> - 10^5 poise) and a rotating crucible viscometer (10^3 - 10^0 poise). The viscosity range corresponds to the temperatures from 700 - 1600 ^0C, i. e. from glassy to molten states. Mechanism of viscous flow is quite different but Fulcher funtion could be applied well to interpolate the viscosity in the mid range of both states. However, it can not be found the correlation between Tg and Fulcher constant To.
2. MgO- and CaO-Al_2O_3-SiO_2 system containing nucreating reagent were used as a glass solder for joining of ceramics. Measured Tg and Tc were used to determined the heat treatment temperatures at which nucreation and crystal growth proceed. After devitrification of solder glass, higher strength of joining were achieved, more than 200 MPa.
3. Molecular dynamic simulation was applied to a viscosity calculation of molten sodium silicate system. Qualitative reproduction were obtained both for temperature and compositional dependence of viscosity. However, it seems to be very hard to reproduce a quantitative result for the transport behavior of such a highly networked systems owing the limitation of capacity of caculater nowadays.
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