【摘要】 采用固相反应法,选取不同压坯成型压力(11~800 MPa)制备了CaCu3Ti4O12陶瓷系列样品。利用X射线衍射、Raman光谱以及扫描电子显微镜研究了成型压力对体系晶体结构和微观形貌的影响,并利用内部阻挡层电容器模型解释了成型压力改变所引起的微观结构变化对体系电性能的影响机理。结果表明在所选成型压力范围内体系未发生结构相变,但其微观形貌却明显受到成型压力的影响;当成型压力大于600 MPa时,样品中大晶粒的出现会提高其介电常数;而成型压力为200 MPa时,样品晶界处肖特基势垒的提高可改善其压敏性能。更多还原

【Abstract】 CaCu3Ti4O12 ceramics were synthesized by solid-state reaction method with different forming pressures(11-800 MPa). The effects of forming pressure on the crystal structure and micro-morphology of samples were studied by X-ray diffraction(XRD), Raman spectroscopy and scanning electron microscopy. The mechanism of the effects of microstructure changes caused by the change of forming pressure on the electrical properties of samples was discussed by the model of internal barriers layer capacitor. The experimental results reveal that no phase transition is observed for all samples, while the micro-morphologies are greatly influenced by the forming pressure. It is believed that the larger grains existed in the samples formed with larger pressure(p>600 MPa) could enhance their permittivities, and the higher Schottky barriers in the sample formed at 200 MPa improve its non-ohmic properties.更多还原