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Journal of the Korean Ceramic Society 1995;32(11): 1269. |
| $GeO_2$의 첨가가 $PbO-Bi_2O_3-Ga_2O_3$ 유리의 안정화에 미치는 영향 |
| 최용규, 허종, 류선윤1 |
포항공과대학교 재료금속공학과, 비정질 무기재료 연구실
1선문대학교 재료공학과 |
| Effects of $GeO_2$ Addition on the Stabilities of $PbO-Bi_2O_3-Ga_2O_3$ Glasses |
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| ABSTRACT |
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Effects of GeO2 addition on the thermal and structural stabilities of PbO-Bi2O3-Ga2O3 glasses were studied. Thermal stabilities, as assessed by the weighted thermal stability factors [(Tx-Tg)/Tg], increased with GeO2 concentraton from 0.097 to 0.210 with the addition of 20 mol% GeO2. Increasing GeO2 content resulted in the decrease of apparent density, molar volume, refractive index and thermal expansion. On the other hand, IR transmission cut-off (λT=50%) moved from 6.73${mu}{textrm}{m}$ for the ternary PbO-Bi2O3-Ga2O3 glass to shorter wavelength side, 5.98${mu}{textrm}{m}$ for a glass containing 20mol% GeO2. There were little change with GeO2 content, however, in the activation energies for the viscous flow of approximately 140 kcal/mole within the temperature interval of 300~50$0^{circ}C$. Addition of GeO2 to PbO-Bi2O3-Ga2O3 glasses enhanced the thermal and structural stabilities significantly at the expense of their infrared transmittance. An appropriate compsomise between these two opposite trends should be made following the specifications of the final applications. |
| Key words:
Heavy metal oxide glasses, $GeO2$, IR transmission, Thermal stability |
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