Textured Ba0.96Ca0.04Ti1−xHfxO3-5BT Ceramics for Multilayer Actuators

BaTiO3-based ceramics are regarded as one of the promising lead-free alternatives to PZT-based ceramics, and their property enhancement remains one of the most important research directions. This study presents Ba0.96Ca0.04Ti1−xHfxO3-5BT (x = 0.05, 0.07, 0.08, 0.09, 0.10) ceramics with enhanced piezoelectric properties using a crystallographic texture strategy. Highly textured Ba0.96Ca0.04Ti1−xHfxO3-5BT ceramics were successfully prepared by the templated grain growth method, and the effects of Hf content in matrix on the phase structure, morphology, and properties of the textured ceramics were investigated. The textured Ba0.96Ca0.04Ti0.93Hf0.07O3-5BT samples achieved a piezoelectric coefficient d33 of 580 pC/N, an electromechanical coupling factor kt of 0.62, and a high unipolar normalized strain Smax/Emax of 1390 pm/V (measured at 10 kV/cm), together with a strain hysteresis Hs as low as 3.7% under 30 kV/cm, demonstrating excellent piezoelectric properties and favorable strain hysteresis. The excellent comprehensive performance can be attributed to the high-quality preferred orientation and the orthorhombic and tetragonal phase coexistence. Moreover, the multilayer textured Ba0.96Ca0.04Ti0.93Hf0.07O3-5BT ceramics were fabricated by internal electrode co-firing method. The multilayer samples with 10 layers produced a displacement of 581 nm under a driving voltage of 250 V. This study demonstrates that textured BCTH-5BT ceramics can serve as promising eco-friendly lead-free candidates for potential piezoelectric actuation applications.