Effects of MnO₂ addition on the electrical properties of lead-free textured potassium sodium niobate-based ceramics

Abstract

In our previous work, we developed lead-free potassium sodium niobate-based textured ceramics with a piezoelectric response (d₃₃*) of 505 pm/V and superior thermal stabilities. However, the dielectric loss of the ceramics is 3.5% at 1 kHz which is higher than the PZT-based ceramics. To solve this problem, MnO₂ was introduced into the KNLN-BZ-BNT ceramics in this work. It is found that the introduction of MnO₂ does not affect the crystalline phase nor grain size. In addition, the effect of MnO₂ of less than 2.0% on the texture degree is insignificant. The 0.5% and 1.0% MnO₂ modified samples show similar electrical properties and thermal stability as the one without MnO₂. The addition of MnO₂ can reduce the dielectric loss. Compared to the ceramic with 0.5% MnO₂ addition, the 1.0% MnO₂-added KNLN-BZ-BNT ceramic possesses a better performance.

Keywords:

• Lead-free piezoelectric KNN-based ceramics
• large piezoelectric strain
• thermal stability
• dielectric properties
• MnO₂ addition

Additional information

Funding

This research was supported by the National Natural Science Foundation of China (Grant nos. 51332003, 51202184, 51602247 and 91323303), the “111 Project” of China (grant no. B14040), the NSF Research Project of Shaanxi Province of China (No. 2017JQ6003), and the Fundamental Research Funds for the Central Universities of China.