研究目的
To study the thermal properties of a series of high-purity zinc-tellurite glasses for fiber-optic applications, including heat capacity, thermal conductivity, density, and coefficient of thermal expansion, and to determine standard thermodynamic functions using a model-statistical approach.
研究成果
The study successfully determined thermal properties and standard thermodynamic functions for zinc-tellurite glasses using DSC and a model-statistical approach. Key findings include heat capacity decrease with increasing ZnO, unchanged glass transition temperature, and increased crystallization resistance at 12.5% ZnO. The data support improving glass production for fiber-optic applications, with potential for extrapolation to other compositions and temperatures.
研究不足
The study is limited to specific glass compositions and temperature ranges. The techniques may have errors, e.g., ±0.2 K for temperature, ±1% for enthalpy, ±3% for heat capacity. The model relies on extrapolation and assumptions, which may not capture all material behaviors. Application is constrained to crucible methods for glass production.
1：Experimental Design and Method Selection:
The study used differential scanning calorimetry (DSC) to measure heat capacity and transitions, pycnometric and Archimedes methods for density, dilatometry for thermal expansion, and a comparative method for thermal conductivity. A model-statistical approach was applied for data processing.
2：Sample Selection and Data Sources:
High-purity glasses with compositions (TeO2)(0.86-x)(ZnO)x(La2O3)0.04(Na2O)0.1 (x = 0.1, 0.125, 0.17, 0.2 mole fractions) were synthesized using oxides melted in platinum crucibles in a sealed silica chamber with purified oxygen.
3：86-x)(ZnO)x(La2O3)04(Na2O)1 (x = 1, 125, 17, 2 mole fractions) were synthesized using oxides melted in platinum crucibles in a sealed silica chamber with purified oxygen.
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: Equipment includes Netzsch STA 409 PC Luxx and DSC 404 F1 Pegasus calorimeters, platinum crucibles, silica glass molds, pycnometers, dilatometer, and heat conductivity meter. Materials include high-purity TeO2, ZnO, La2O3, Na2CO3, Al2O3 reference sample, distilled water, indium, and tin.
4：Experimental Procedures and Operational Workflow:
Glasses were synthesized at 1073 K, cast into molds, annealed, and polished. DSC measurements were performed at heating rates of 2.5, 5, and 10 K/min in argon flow. Density was measured using pycnometric and Archimedes methods. Thermal expansion was measured with a dilatometer. Thermal conductivity was measured using DSC with metal melting and a comparative heat flux method.
5：5, 5, and 10 K/min in argon flow. Density was measured using pycnometric and Archimedes methods. Thermal expansion was measured with a dilatometer. Thermal conductivity was measured using DSC with metal melting and a comparative heat flux method.
Data Analysis Methods:
5. Data Analysis Methods: Data were processed using nonlinear regression for model parameters, with software like NETZSCH Proteus?. Thermodynamic functions were calculated based on statistical models.
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