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.