Sintering behavior, dielectric and piezoelectric properties of sodium potassium niobate-based ceramics prepared by single step and two-step sintering

In this work (1–x) K0.48Na0.48Li0.04Nb0.96Ta0.04O3–xSrTiO3 (0.0≤x≤0.10) ceramics were fabricated via single step sintering (SSS) as well as two-step sintering (TSS) methods. Investigation of the sintering behavior of ceramics revealed that TSS could reduce sintering temperature effectively and it enhances densification. The relative densities of TSSed ceramics were about 3% higher than SSSed ones. Coexistence of orthorhombic and tetragonal symmetries in ceramic containing 1% SrTiO3, resulted in maximum piezoelectric constant compared to others. Higher density and lower alkali elements loss in TSSed ceramics improved dielectric and piezoelectric properties compared to SSSed ceramics. Piezoelectric constant of the 0.99KNNLT–0.01ST ceramic sintered via SSS and TSS was measured at 208 and 278 pC/N, respectively.