| Project/Area Number |
09650741
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | Kumamoto Institute of Technology |
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Principal Investigator |
KODAMA Masao Kumamoto Institute of Technology Faculty of Engineering, Department of Applied Chemistry Professor, 工学部, 教授 (50111050)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Keywords | Glass / Alkali metal germanates / Alkali metal borates / Velocity of sound / Elastic constants / Glass transition / Thermal analysis / ゲルマニウム酸塩異常 |
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| Research Abstract |
[Objective] Alkali borate glasses and alkali germanate glasses exhibit peculiar properties termed borate anomalies and germanate anomalies, respectively. The purpose of the present research is to elucidate similarities and differences between alkali borate glasses and alkali germanate glasses from the velocity of soud and elastic properties of these glasses.
[Experimental] For the binary alkali metal germanate glasses xM_2O(1 - x)GeO_2 where M = Li, Na, K, Rb and Cs, the density and the velocity of sound were determined. (1) A powder synthesized chemically from alkali metal hydroxide and quartz-type germanium dioxide was fused in a platinum crucible at temperatures from 1100 to 1450ﾟC for 2 h and then the liquid was poured into a graphite mold to form a cylindrical bulk glass. (2) The contents of alkali metal and germanium dioxide were determined by a potentiometric titrimetry. (3) The glass transition temperature and the change in heat capacity at the glass transition were determined by a differential scanning calorimeter. (4) The density was measured
by a hydrostatic weighing method. (5) The ultrasonic velocity was measured at a frequency of 10 MHz by means of the pulse-echo overlap method.
[Results and Discussion] The velocity of sound and the elastic constants of alkali germanate glasses wed single maxima at the composition of x = 0.15-0.20. This behavior is different from the behavior of alkali borate glasses : (1) the velocity in lithium borate glasses increases monotonically with an increase in the content of lithium oxide, (2) the velocity in sodium and potassium borate glasses shows a single maximum, (3) the velocity in rubidium and caesium borate glasses exhibits a maximum, a minimum and another maximum in succession. Since the papers for germanate glasses are in preparation, the papers for borate glasses are given in References.
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