研究目的
To study the effect of KNbO3 incorporation on the structure, thermal, optical, and physical properties of gallate-based glasses, specifically in the system (100-x)(69GaO3/2-11LaO3/2-20KO1/2) – x KNbO3, and to determine the solubility limit of niobium oxide in these glasses.
研究成果
The incorporation of KNbO3 up to 14 mol.% in gallate glasses facilitates glass formation and increases refractive index due to niobium's high polarizability, while maintaining a broad IR transmission window. The glass network consists of tetrahedral GaO4 and octahedral NbO6 units, with K+ and La3+ ions providing charge compensation. However, higher concentrations lead to phase separation and reduced thermal stability. These findings highlight the potential for optical applications but indicate limitations in niobium solubility and thermal properties.
研究不足
The study is limited to specific glass compositions and may not generalize to other systems. The thermal stability decreases with higher KNbO3 content, and phase separation occurs above 14 mol.%, restricting practical applications. High-temperature viscosity behavior and crystallization mechanisms require further investigation. The use of small batch sizes and specific synthesis conditions may affect scalability.
1：Experimental Design and Method Selection:
The study uses a traditional melt and quenching technique to synthesize glasses with varying KNbO3 content. Thermal, optical, and structural properties are characterized using differential scanning calorimetry (DSC), thermomechanical analysis (TMA), viscosity measurements, refractive index measurements, UV-Vis-NIR and IR spectroscopy, and Raman spectroscopy to investigate the structure-properties relationship.
2：Sample Selection and Data Sources:
Glass samples are prepared with x = 0, 5, 10, 14, 17, and 20 mol.% KNbO3. Nominal compositions are verified by electron probe micro-analysis (EPMA).
3：Nominal compositions are verified by electron probe micro-analysis (EPMA).
List of Experimental Equipment and Materials:
3. List of Experimental Equipment and Materials: Equipment includes a platinum-gold crucible for melting, Mettler Toledo XSE204 densimeter for density measurements, Netzsch DSC/DTA Pegasus 404F3 for thermal analysis, Netzsch TMA 402 F1 for TEC measurements, Theta US parallel-plate viscometer for viscosity, Metricon 2010/M for refractive index, Agilent Cary 50 for UV-Vis-NIR spectra, Bruker Equinox 55 for FTIR spectra, and Renishaw inVia Raman spectrometer for structural analysis. Materials include Ga2O3, La2O3, K2CO3, and KNbO3 powders.
4：Experimental Procedures and Operational Workflow:
Powders are mixed, melted at 1400°C for 1 hour, cast into a preheated mold, annealed, cut, and polished. Measurements are conducted as per standard protocols for each characterization technique.
5：Data Analysis Methods:
Data are analyzed using Gaussian peak fitting for Raman spectra, slope calculations for TEC, and conversion to linear absorption coefficients for optical spectra. Statistical errors are provided for measurements.
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