研究目的
Investigating the phase transition behavior of BaTiO3 nanopowders and the effects of coating with different shell materials on phase structure and dielectric properties in core-shell structured ceramics.
研究成果
The research demonstrates that internal stress from thermal expansion mismatch between core and shell suppresses the cubic to tetragonal phase transition in BaTiO3-based ceramics. Tailoring shell composition and core/shell ratio can reduce this stress, allowing phase transition and improved dielectric properties, with tetragonal core materials yielding higher dielectric constants.
研究不足
The study may have limitations in the scalability of synthesis methods, potential impurities in nanopowders, and the complexity of controlling internal stress precisely in core-shell structures. Optimization could involve exploring more shell compositions and advanced characterization techniques.
1：Experimental Design and Method Selection:
The study involved synthesizing BaTiO3 nanopowders using alkoxide-hydroxide and hydrothermal methods, coating them with 0.3BZT-0.7BT or 0.03Nb2O5-0.01Co2O3 via chemical coating methods, and sintering to form ceramics. The rationale was to investigate phase transitions and internal stress effects in core-shell structures.
2：3BZT-7BT or 03Nb2O5-01Co2O3 via chemical coating methods, and sintering to form ceramics. The rationale was to investigate phase transitions and internal stress effects in core-shell structures.
Sample Selection and Data Sources:
2. Sample Selection and Data Sources: BaTiO3 nanopowders were synthesized with specific methods; coated powders were prepared with varying shell compositions and ratios. Data came from XRD, Raman spectroscopy, SEM, TEM, thermal dilatometry, and dielectric measurements.
3：List of Experimental Equipment and Materials:
Equipment included X-ray diffractometer (X′Pert PRO, PANalytical), Raman microscope (InVia, RENISHAW), FESEM (Ultra Plus, Zeiss), TEM (JSM2010, JEOL), thermal dilatometer (Model402, Netzsch), LCR meter (HP 4284A, Polyk), and temperature-controlled chamber (EC1A, Polyk). Materials included barium hydroxide octahydrate, tetrabutyl titanate, zinc acetate dehydrate, barium acetate, bismuth nitrate, niobium hydroxide, cobalt nitrate, citric acid, and others as specified.
4：Experimental Procedures and Operational Workflow:
Synthesis of BT nanopowders, coating with shell materials, pellet pressing, sintering at 1150-1300°C, and characterization using XRD, Raman, SEM, TEM, thermal expansion, and dielectric property measurements.
5：Data Analysis Methods:
Rietveld refinements using GSAS software for XRD data, analysis of Raman spectra, and interpretation of dielectric and thermal expansion data.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
