New potassium-sodium niobate lead-free piezoceramic: Giant-d33 vs. sintering temperature

The objective of this work is to achieve a giant piezoelectric constant in (K, Na)NbO3-based lead-free ceramics, and then 0.96K(0.46)Na(0.54)Nb(0.95)Sb(0.05)O(3)-0.04Bi(0.5)(Na0.82K0.18)(0.5)ZrO3 lead-free piezoceramics were designed and prepared by optimizing the sintering temperature (T-S). The rhombohedral-tetragonal phase boundary is found in the ceramics sintered at 1070 similar to 1105 degrees C and is suppressed when sintered at low T-S of 1060 similar to 1065 degrees C. The threshold for T-S is 1070 degrees C in terms of their ferroelectric and piezoelectric properties owing to the difference in the phase boundary and the microstructure, and a large d(33) of 388 similar to 465 pC/N could be attained in a wide T-S range of 1070 similar to 1105 degrees C, benefiting their practical applications because of broad T-S. More interestingly, the ceramic sintered at 1075 degrees C has a giant d(33) of similar to 465 pC/N. We think that such a giant d(33) of this material system can benefit the development of (K, Na) NbO3-based piezoceramics. (C) 2014 AIP Publishing LLC.