Enhanced piezoelectric properties and electrical resistivity in CaHfO3 modified BiFeO3BaTiO3 lead-free piezoceramics

Significant impact of TiO2 purity on the phase structure and electrical properties of BiFeO3–BaTiO3 lead‐free piezoelectric ceramics

“…The XRD patterns of 0.7BF-0.3BT ceramics are shown in Figure 1A, revealing a typical ABO 3 perovskite structure composed of cubic (C, Pm 3m) and rhombohedral (R, R3c) phases for all compositions. All ceramics contain a slight fraction of the impurity of Bi 25 FeO 40 , which is a common secondary phase. 35 As shown in the magnified image on the right side of Figure 1A, there is a weak split peak in the (1 1 1) diffraction peak near 39 • in the BF-BT_1 sample and (1 1 1) diffraction peak splitting enhancement of BF-BT_2, BF-BT_3, and BF-BT_4, which indicates the coexistence of R-and C-phases at room temperature.…”

“…However, excessive t d or T S contributed to the volatilization of Bi 2 O 3 to deteriorate piezoelectric properties 13,14 . Furthermore, numerous reports have shown that the substitution of other ions (A‐site: La 15 and Nd 16,17 ; B‐site: Al, 18 Ga, 4 Co, 19 Mg 1/2 Ti 1/2 , 20 Mg 2/3 Nb 1/3 , 21 Zn 1/2 Ti 1/2 , 22 Zn 2/3 Nb 1/3 , 23 and Ni 1/2 Ti 1/2 24 ; A‐ and B‐site: CaHfO 3 25 ) for A/B sites can reduce oxygen vacancies ($$V_O^{ \cdot \cdot }$$) and improve the electrical resistance of BF–BT‐based ceramics.…”

Bismuth Ferrite-Based Lead-Free High-Entropy Piezoelectric Ceramics

“…(1– x )­BiFeO 3 – x (Ba 0.2 Sr 0.2 Ca 0.2 Bi 0.2 Na 0.2 )­TiO 3 (BF– x BSCBNT, x = 0.15–0.50) lead-free ceramics were prepared by a solid-state reaction, using Na 2 CO 3 (99.98%, Aladdin), Bi 2 O 3 (99.9%, Aladdin), TiO 2 (99%, Aladdin), SrCO 3 (99.95%, SINOPHARM), BaCO 3 (99.9%, SINOPHARM), Fe 2 O 3 (99.9%, Aladdin), and CaCO 3 (99.99%, Aladdin) as raw materials. The appropriate amount of starting compound was ball milled with ZrO 2 balls in ethanol for 24 h. After drying, the mixture was calcined at 700–750 °C for 3 h. The calcined powder was mixed with 0.1 wt % MnO 2 (>99%) and then ball milled in ethanol for a second time for 24 h. The addition of MnO 2 is expected to reduce the leakage current in BF-based piezoceramics and enhance the resistivity. , After drying, the binder (PVB) was dripped into the dried powder for granulation, and then the powder was pressed into green pellets of 10 mm in diameter and ∼1 mm in thickness using a pressure of 127 MPa. After the binder was removed at 600 °C, the pellets were sintered at 960–1080 °C for 3 h to obtain ceramics.…”

Improved piezoelectric properties in Bi(Mg2/3Nb1/3)O3‐modified BiFeO3–BaTiO3 lead‐free piezoelectric ceramics

“…The presence of inhomogeneous element distributions in the core-shell microstructure can be attributed to the microsegregation of elements formed during the slow cooling process of sintering, as well as the immiscibility of the dominantly ionically bonded BT and covalently bonded BF. 2,20,36,43,51,[55][56][57][58][59][60][61] The temperature-dependent relative permittivity (ε r ) and dielectric loss (tanδ) for the BF-0.30BT-xBMN and BF-yBT-0.03BMN ceramics are plotted in Figure 3A,B, respectively. The measurements were carried out in the range of room temperature to 600 • C at a frequency of 10 kHz.…”