Influence of Structural Phase Transitions on the Mechanical Behavior of Lead-Free Potassium Sodium Niobate Piezoceramics

• Applicants: Professor Dr.-Ing. Jürgen Rödel; Professor Dr. Kyle Grant Webber
• Subject Area: Synthesis and Properties of Functional Materials
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 392442956

A growing critical environmental issue exists related to the increasing use of toxic lead-based piezoelectric ceramics for various sensor and actuator applications. There have been substantial scientific and industrial efforts towards the development of lead-free alternatives, which have led to the identification of various potential material systems. Polycrystalline (KxNa1- x)NbO3 (KNN) remains one of the most promising candidates, with a high Curie point, stable electromechanical response over a wide usable temperature range, high acoustic vibration velocities, and low density. Despite the numerous advancements in tailoring the electromechanical properties, there has been very little work on understanding the mechanical response, in particular the fracture behavior, which is crucial for reliable commercial implementation. During operation piezoelectric ceramics are often exposed to high operating temperatures and large compressive stress, used to reduce cracking. Therefore, the aim of this project is to use combined and complementary experimental techniques and expertise in Germany and China to characterize the temperature-dependent mechanical properties and in situ stress-dependent crystal structure of KNN with various advanced novel measurement techniques.

• DFG Programme: Research Grants
• International Connection: China
• Partner Organisation: National Natural Science Foundation of China
• Cooperation Partners: Professor Jing-Feng Li, Ph.D.; Professor Ke Wang, Ph.D.