Development of perovskite-type ceramics and device structures for electrocaloric applications

开发用于电热应用的钙钛矿型陶瓷和器件结构

• 批准号: 226707148
• 负责人: Dr.-Ing. Sylvia Gebhardt
• 金额: --
• 依托单位: Fraunhofer-Institut für Keramische Technologien und Systeme (IKTS)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/226707148?language=en
• 关键词: Development; perovskite; type; ceramics; device

This proposal is part of the topical key area dealing with the development of electrocaloric materials for ferroic cooling systems. Specific emphasis is given to the implementation of known and novel electro-ceramic materials into future device structures by using ceramic processes. Two different perovskite-type formulations will be considered: first PMN-PT and secondly BaTiO3. For both compositions, electrocaloric effect has been reported in literature. Modifications of chemical composition in correlation to the specific technology requirements and performance of elements are done as part of own research. In order to limit the operation voltage, reduced thickness of the refrigerant material is necessary. Complimentary to the thin film approach we here consider ceramic powder technologies, which allow for high volume refrigerants. To achieve film thicknesses of 5-50 µm multilayer technology will be applied to build electrocaloric (EC) elements. Influence of multilayer structure (geometrical size, thickness and number of layers; material and thickness of inner electrodes) on dielectric, ferroelectric and electrocaloric properties will be investigated in detail. The development of device structures will be accompanied by a productive and hierarchical structured characterization methodology for measurement of dielectric and ferroelectric properties. Besides, measuring set-up for direct determination of EC effect on large components (< 500 mm2) will be developed. Exchange of test samples and comparison of measurement results contribute to the development of guidelines for reliable measurements and characterization of electrocaloric materials within SPP 1599. The cooling performance of prepared device structures will be systematically characterized aiming at knowledge gain on the correlation between chemical composition, microstructure, device design and operational modes. In view of the development of electrocaloric cooling systems in the consortium, experimental investigations of rate dependent heat release and heat adsorption in dependence of the applied voltage signal will be performed. Results will be compared to simulated data using coupled electrical and thermal analysis. Kinetic approaches are proved to see if they are useful for simplified cooling systems without mechanical switches. Suitable application areas will be identified. In cooperation with project partners of the SPP consortium EC cooling elements in form of ceramic multilayer structures will be integrated into cooling systems. Therefore, we will consider key problems of performance increase and stability under practical operation conditions in experimental studies. Materials, device design and operation modes are tailored to increase cooling efficiency.

本提案是处理用于铁冷却系统的电热材料发展的专题关键领域的一部分。特别强调的是通过使用陶瓷工艺将已知的和新颖的电陶瓷材料实现到未来的器件结构中。将考虑两种不同的钙钛矿型配方：第一种是PMN-PT，第二种是BaTiO3。对于这两种组合物，已有文献报道电热效应。根据特定的技术要求和元素的性能对化学成分进行修改，作为自己研究的一部分。为了限制工作电压，必须减小制冷剂材料的厚度。与薄膜方法互补，我们在这里考虑陶瓷粉末技术，它允许大容量制冷剂。为了实现5-50µm的薄膜厚度，将应用多层技术来构建电热（EC）元件。多层结构（几何尺寸、厚度和层数；内电极的材料和厚度）对介电、铁电和电热性能的影响将被详细研究。器件结构的发展将伴随着一种用于测量介电和铁电性质的生产性和分层结构表征方法。此外，将开发用于直接测定大组分（< 500 mm2） EC效应的测量装置。测试样品的交换和测量结果的比较有助于制定spp1599中可靠测量和表征电热材料的指南。针对化学成分、微观结构、器件设计和操作模式之间的关系，将系统地表征所制备器件结构的冷却性能。鉴于该联盟的电热冷却系统的发展，实验研究速率依赖的热释放和热吸附依赖于施加的电压信号将进行。结果将与使用耦合电和热分析的模拟数据进行比较。动力学方法被证明是否适用于没有机械开关的简化冷却系统。确定合适的应用领域。与SPP财团的项目伙伴合作，欧共体的多层陶瓷结构冷却元件将集成到冷却系统中。因此，我们将在实验研究中考虑实际操作条件下性能提高和稳定性的关键问题。材料，设备设计和操作模式量身定制，以提高冷却效率。