Development of high-temperature stable piezoelectric materials and electrodes

高温稳定压电材料及电极的开发

• 批准号: 5406737
• 负责人: Professor Dr.-Ing. Holger Fritze
• 金额: --
• 依托单位: Arbeitsbereich Sensorik von Hochtemperaturprozessen
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2006-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5406737?language=en
• 关键词: Development; temperature; stable; piezoelectric; materials

Electrical losses in piezoelectric materials and the stability of the electrodes were identified by our group as the limiting factors of piezoelectric devices in the temperature range up to 1300 °C. Highly attractive sensor and actuator applications are not feasible due to temperature limitations. The most promising high temperature piezoelectric materials are langasite (La3Ga5SiO14) and gallium orthophosphate (GaPO4) exhibiting a phase stability up to about 1470 °C and 930 °C, respectively. Our group is presently investigating the high temperature properties of langasite. Therefore, the emphasis of the proposed research is on the latter material. Despite the temperature limit of 930 °C, the study of gallium orthophosphate is justified by the extremely low electrical losses at temperatures up to 900 °C. The first part of the project includes the investigation of the piezoelectric behavior, of the microstructural and compositional changes during operation and of their correlation with the crystal growth conditions. The electrodes of resonant devices experience extremely high accelerations. They must represent a good compromise on high conductivity and low mass. The mechanical properties must be nearly gas atmosphere and temperature independent to avoid disturbances of the resonance behavior. Consequently, the demands on electrodes for resonant devices exceed those for common high temperature electrodes. Therefore, the objective of the second part of the project is the investigation and improvement of the electrode properties including chemical and thermal stability, electrical conductivity, adhesive strength as well as electrode oxidation and non-stoichiometry in the temperature range up to 1300 °C. Proposed starting materials are Pt-Rh alloys, TiN and La0.3Sr0.7CrO3.

压电材料中的电损耗和电极的稳定性被我们的小组确定为压电器件在高达1300 °C的温度范围内的限制因素。由于温度限制，高度吸引人的传感器和致动器应用是不可行的。最有前途的高温压电材料是硅酸镓镧（La 3Ga 5SiO 14）和正磷酸镓（GaPO 4），它们分别表现出高达约1470 °C和930 °C的相稳定性。我们小组目前正在研究硅酸镧镓的高温性能。因此，建议研究的重点是后者的材料。尽管温度限制为930 °C，但正磷酸镓的研究是合理的，因为在高达900 °C的温度下，其电损耗极低。该项目的第一部分包括压电行为的调查，在操作过程中的微观结构和成分的变化，以及它们与晶体生长条件的相关性。谐振装置的电极经历极高的加速度。它们必须代表高导电性和低质量的良好折衷。机械性能必须几乎与气体气氛和温度无关，以避免共振行为的干扰。因此，对用于谐振装置的电极的要求超过了对普通高温电极的要求。因此，该项目第二部分的目标是研究和改进电极性能，包括化学和热稳定性，导电性，粘合强度以及电极氧化和温度范围高达1300 °C的非化学计量比。拟定的起始材料为Pt-Rh合金、TiN和La0.3Sr0.7CrO3。