Phase transitional behavior and electrical properties of (1 − x)(K0.475Na0.48Li0.05)Nb0.95Sb0.05O3–xCaZrO3 lead-free ceramics

•A new (K,Na)NbO3-based lead-free piezoelectric ceramic system was projected.•Constructing both R–O and O–T phase boundaries at near room temperature.•The phase boundary results in a significantly enhanced piezoelectric activity.•The phase transitional behavior of the ceramics was explicitly demonstrated.

Lead-free piezoelectric ceramics (1−x)(1−x)(K0.475Na0.48Li0.05)Nb0.95Sb0.05O3–xCaZrO3 with perovskite structure were prepared by conventional ceramic sintering technique, and the effects of the CaZrO3 content on the phase transitions, dielectric and piezoelectric properties of the ceramics were investigated. With the increase of CaZrO3, the crystal structure of the ceramics transformed from the orthorhombic–tetragonal phase coexistence to the coexistence of rhombohedral and orthorhombic phases at x=0.01x=0.01. Furthermore, both the rhombohedral–orthorhombic and orthorhombic–tetragonal phase transitions of the ceramics were found adjusted to be near room temperature with x=0.005x=0.005, which results in a significantly enhanced piezoelectric activity.