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

Abstract 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 ∼792°C) Aurivillius‐type sodium bismuth niobate, Na 0.5 Bi 2.5 Nb 2 O 9 (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 ∼ 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 δ = 2.5% (@ 100 kHz) and high dc electrical resistivity ρ of 7.5 MΩ cm at 500°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.