The Effect of Bi_0.5Li_0.5ZrO₃-SrSnO₃ Composite Doping on the Construction of Polymorphic Phase Boundaries and Enhanced Electrical Properties of K_0.45Na_0.55Nb_0.965Sb_0.035O₃ Piezoelectric Ceramics

In this experiment, a new lead-free piezoelectric ceramics (1−x)K0.45Na0.55Nb0.965Sb0.035O3−x(0.9Bi0.5Li0.5ZrO3−0.1SrSnO3) were prepared by the conventional solid-phase method, and the effects of the doping amount of 0.9Bi0.5Li0.5ZrO3−0.1SrSnO3 on the K0.45Na0.55Nb0.965Sb0.035O3 ceramics on the crystal structure, microstructure, microscopic structure and electrical properties. All the doping ions entered the KNN lattice and formed a dense solid solution with a single-phase structure, and the phase structure of the ceramics coexisted from orthorhombic (O) to orthorhombic-tetragonal (O-T) phases in the range of 0 ≤ x ≤ 0.03, and transitioned to rhombohedral-tetragonal (R-T) phase coexistence when 0.035 ≤ x ≤ 0.05. The electrical properties of the ceramics were analyzed and the polymorphic phase boundary (PPB) region was obtained at x = 0.035 and had the best overall properties: d 33 = 324pC/N, k p = 49%, ε r = 1479, tanδ = 3.21%, P r = 31.98 μC/cm2, E c = 16.83 kV cm−1 and T C = 293°C. By The microstructural analysis of the ceramics showed that the appropriate amount of compound doping of the second element enhances the denseness of the ceramics as well as makes the grains uniformly distributed. These results indicate that the ceramics of this system have great prospects for future applications in the field of lead-free piezoelectric ceramics.