研究目的
To design a new type of Mg and K codoped BST powders, prepare them by a sol-gel method, and study the effect of doped concentration on the dielectric properties, including comparisons with pure, Mg doped, and K doped BST powders.
研究成果
Mg and K codoping effectively reduces dielectric constants and losses in BST powders, with specific compositions (e.g., 2% Mg, 2% Mg 2% K, 2% Mg 5% K) showing low and stable properties suitable for tunable microwave applications. The dielectric properties are influenced by crystallization, doping mechanisms, and morphology.
研究不足
The study is limited to powder form and specific doping concentrations; results may not directly apply to films or other forms. The mechanisms for some behaviors, like the dielectric constant of 20% K doped powder, require further study. The method may have scalability or reproducibility issues in industrial applications.
1:Experimental Design and Method Selection:
BST powders were prepared using a sol-gel method, chosen for its cost-effectiveness and convenience. The method involved preparing precursor solutions and sols, drying to form xerogels, milling, and heat treatment at 900°C for 4 hours. XRD and SEM were used for structural and morphological analysis, and dielectric properties were measured using an impedance analyzer.
2:Sample Selection and Data Sources:
Samples included pure BST, Mg doped (2%), K doped (2% to 20%), and Mg-K codoped (2% Mg with 2% to 20% K) powders. Data were obtained from laboratory-prepared samples.
3:List of Experimental Equipment and Materials:
Equipment included a magnetic stirrer, muffle furnace, SEM, XRD, and E4991A impedance analyzer. Materials included glacial acetic acid, barium acetate, strontium acetate, ethylene glycol methyl ether, butyl titanate ester, acetylacetone, magnesium acetate, potassium precursor (implied), paraffin, and crucibles.
4:Experimental Procedures and Operational Workflow:
Steps involved heating and stirring glacial acetic acid, adding acetates and titanate, adding solvents and complexing agents, mixing doped solutions ultrasonically, drying at 110°C, milling, sintering at 900°C, pressing into discs with paraffin, and measuring dielectric properties from 50 MHz to 1 GHz.
5:Data Analysis Methods:
XRD patterns were analyzed for phase structure, lattice parameters, and grain sizes using FWHM. SEM images were used for morphological observation. Dielectric constant and loss were measured and analyzed for stability and values.
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