High mechanical quality factor and piezoelectricity in potassium sodium niobate ceramics

Plenty of works have done to enhance the piezoelectricity of potassium-sodium niobate (KNN), aiming to replace lead-zirconate titanate (PZT) in the consideration of eco-friendly requirement. However so far, KNN ceramics with high piezoelectric performances tend to have a low mechanical quality factor (Qm), which could result in excessive dielectric loss, especially when working in high frequencies. Thus, increasing Qm is a crucial task in KNN-based ceramics. By constructing phase boundaries together with inducing oxygen vacancies, a new KNN ceramic system is built by using conventional solid-state method with high Qm (>250), high piezoelectric performance as well as outstanding temperature stability. Optimum overall properties of KNN-based ceramics can be as large as d33 = 231 pC/N, Qm = 355, TC = 366 degrees C. This work provides a deeper insight to KNN-based ceramics with high mechanical quality factor and makes a progress on the high frequency application of lead-free ceramics.

Automated summary

Research has been conducted to enhance the piezoelectricity of KNN ceramics as a more eco-friendly alternative to PZT. However, high-performance KNN ceramics often suffer from low mechanical quality factors, leading to excessive dielectric loss. This study successfully improves the mechanical quality factor of KNN ceramics by constructing phase boundaries and inducing oxygen vacancies, resulting in ceramics with high Qm, high piezoelectric performance, and outstanding temperature stability.