Spark plasma sintering of sodium bismuth niobate that exhibits superior piezoelectric performance

High-performance piezoelectric ceramic materials are required for piezoelectric sensors under harsh conditions in nuclear power plants, aeronautics, and aerospace. In this work, a lead-free high-Curie-temperature (T-C similar to 792 degrees C) Aurivillius-type sodium bismuth niobate, Na0.5Bi2.5Nb2O9 (NBN), was fabricated through spark plasma sintering (SPS). The textured NBN ceramics with a high orientation factor of 83% exhibit significantly enhanced piezoelectric performance with a piezoelectric constant d(33) of 31.2 pC/N, three times higher than that of nontextured NBN (d(33) similar to 11.6 pC/N). More importantly, the textured NBN ceramics maintain excellent electrical properties at high temperature, with a high in situ d(33) of 35.9 pC/N, very low dielectric loss tan delta = 2.5% (@ 100 kHz) and high dc electrical resistivity rho of 7.5 M Omega cm at 500 degrees C. These results suggest that the textured NBN ceramics are good high-temperature piezoelectric ceramic materials, and have promising applications in the field of high-temperature piezoelectric sensors.