Ba 0.85 Ca 0.15 Zr 0.9 Ti 0.1 O 3 (BCZT) ceramics with various grain sizes were fabricated through solid-state method followed by different sintering temperatures. The influences of grain size and phase structure on the electric properties and energy storage performance were systematically investigated. The remnant polarization and quasi-static piezoelectric constant of BCZT samples increase gradually as grain size increases, and the samples with the grain size of 44.37 µm exhibit excellent ferroelectricity and piezoelectricity (2 P r = 25.4 µC/cm 2 , d 33 = 513 pC/N). Although the energy storage density of BCZT samples with the grain size of 8.28–44.37 µm is relative lower, all the ceramic samples have higher energy storage efficiency (82–87.4%). There is the maximum energy storage density in phase transition temperature of tetragonal–cubic phase for all BCZT ceramics and the maximum energy storage density first increases and then decreases with the increase of grain size. But the energy storage density of BCZT ceramics near room temperature decreases with increasing of grain size. The smaller grain size is beneficial to improve the room temperature energy storage density of BCZT samples and is disadvantageous to obtaining superior ferroelectric and piezoelectric properties.
Improving fracture toughness, electrical conductivity, and biocompatibility has consistently presented challenges in the development of artificial bone replacement materials. This paper presents a new strategy for creating high-performance, multifunctional composite ceramic materials by doping graphene oxide (GO), which is known to induce osteoblast differentiation and enhance cell adhesion and proliferation into barium calcium zirconate titanate (BCZT) ceramics that already exhibit good mechanical properties, piezoelectric effects, and low cytotoxicity. Using fast hot-pressed sintering under vacuum conditions, (1 −x)(Ba0.85Ca0.15Zr0.1Ti0.9)O3−xGO (0.2 mol% ≤x≤ 0.5 mol%) composite piezoelectric ceramics were successfully synthesized. Experimental results revealed that these composite ceramics exhibited high piezoelectric properties (d33= 18 pC/N,kp= 62%) and microhardness (173.76 HV0.5), meeting the standards for artificial bone substitutes. Furthermore, the incorporation of graphene oxide significantly reduced the water contact angle and enhanced their wettability. Cell viability tests using Cell Counting Kit-8, alkaline phosphatase staining, and DAPI staining demonstrated that the GO/BCZT composite ceramics were non-cytotoxic and effectively promoted cell proliferation and growth, indicating excellent biocompatibility. Consequently, with their superior mechanical properties, piezoelectric performance, and biocompatibility, GO/BCZT composite ceramics show extensive potential for application in bone defect repair.
Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 (BCZT) ceramics were successfully synthesized by controlling the cooling rate during the sintering, and their microstructure and electrical properties were systematically analyzed. The results indicate that all BCZT ceramics show the coexistence of orthorhombic (O) and tetragonal (T) phases near room temperature. As a result of the interaction of grain size and densification , the remnant polarization, dielectric constant, and piezoelectric constant increase firstly and then decrease with the rise of cooling rate. The piezoelectric responses of BCZT ceramics are improved by optimizing the cooling process. BCZT ceramics prepared by the cooling rate with 4 °C/min have high dielectric constant ( ε m = 23879), high remnant polarization (2 P r = 30.26 μC/cm 2 ), and excellent piezoelectric responses ( d 33 = 551.1 pC/N and d 33 * = 630 pm/V), which is due to the coexistence of O-T phase, larger grain size, and superior densification. These findings demonstrate that excellent piezoelectric properties for BCZT ceramics can be achieved by optimizing the cooling rate during the sintering process .
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