| Autor: |
Rabinal, MK, Rao, Ramesh N, Sangunni, KS, Gopal, ESR |
| Rok vydání: |
1994 |
| Předmět: |
|
| Zdroj: |
IndraStra Global. |
| ISSN: |
2381-3652 |
| Popis: |
Differential scanning calorimetric studies have been carried out on $Ge_xSe_{80-x}Pb_{20}$ (17⩽×⩽24) bulk glasses, which exhibit a change from p- to n-type conduction at x=21 at.%. All the samples show a single-stage crystallization followed by a single-stage glass transition. The dependence of glass transition temperature $(T_g)$ on composition shows a maximum at x=21 at.%. Structural relaxation around the glass transition has been studied by measuring $T_g$ as a function of heating rate $(\beta)$. Values of activation enthalpies $(E_g)$ of the glass transition for different samples reveal that chemical bond breaking in the process of structural relaxation at $T_g$ cannot be ignored. Crystallization kinetics have been analysed using the Kissinger method. The crystallization activation energy $(E_c)$ and the frequency factor $(C_0)$, calculated using the above method for different compositions, show anomalies at x=21 at.%. All the samples show the existence of two distinct melting points. The observed compositional dependence of $T_g$, $E_c$ and $C_0$ is discussed using the chemically ordered network model (34 refs.) |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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