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Bending strength of commercially relevant lead‐free piezoceramics – 0.935Na0.5Bi0.5TiO3‐0.065BaTiO3 (NBT‐6.5BT) with and without acceptor Zn‐doping and 0.92(K0.5Na0.5)NbO3‐0.02(Bi0.5Li0.5)TiO3‐xBaZrO3; x = 0.06, 0.07 (KNN‐BZ100x) have been quantified using 4‐point bending tests and contrasted to that of commercial lead zirconate titanate (PZT, PIC151). The compressive and tensile strength probed using additional strain gauges under 4‐point bending indicate negligible non‐linear deformation, in stark contrast to that of commercial PIC151. The bending strength of KNN‐BZ100x is about 100 MPa, comparable to PIC151, while that of NBT‐6.5BT‐based materials is about twice that of PIC151 at ∼160 MPa. These results are rationalized based on the intrinsic characteristics of the lead‐free piezoceramics in terms of fracture toughness, coercive stress, and Young's modulus. Weibull statistics indicate a higher fracture probability for KNN‐based materials, with NBT‐6.5BT‐based materials featuring Weibull modulus twice that of KNN‐based materials. [ABSTRACT FROM AUTHOR]

A series of morphotropic phase boundary (MPB) compositions of (1–x)Na1/2Bi1/2TiO3‐xBaTiO3 (x = 0.05, 0.055, 0.06, 0.065, 0.07), with and without 0.5 mol% Zn‐doping was synthesized using the solid‐state route. The samples were characterized using X‐ray diffraction, dielectric analysis, and electromechanical measurements (piezoelectric d33 coefficient, coupling factor kp, mechanical quality factor Qm, and internal bias field Ebias). The increase in the ferroelectric‐relaxor transition temperature upon Zn‐doping was accompanied by a shift of the MPB toward the Na1/2Bi1/2TiO3‐rich side of the phase diagram. Higher tetragonal phase fraction and increased tetragonal distortion were noted for Zn‐doped (1 – x)Na1/2Bi1/2TiO3‐xBaTiO3. In addition, ferroelectric hardening and the presence of an internal bias field (Ebias) were observed for all doped compositions. The piezoelectric constant d33 and the coupling coefficient kp decreased by up to ∼30%, while a 4‐ to 6‐fold increase in Qm was observed for the doped compositions. Apart from establishing a structure–property correlation, these results highlight the chemically induced shift of the phase diagram upon doping, which is a crucial factor in material selection for optimal performance and commercialization. [ABSTRACT FROM AUTHOR]

A series of morphotropic phase boundary (MPB) compositions of (1–x)Na1/2Bi1/2TiO3‐xBaTiO3 (x = 0.05, 0.055, 0.06, 0.065, 0.07), with and without 0.5 mol% Zn‐doping was synthesized using the solid‐state route. The samples were characterized using X‐ray diffraction, dielectric analysis, and electromechanical measurements (piezoelectric d33 coefficient, coupling factor kp, mechanical quality factor Qm, and internal bias field Ebias). The increase in the ferroelectric‐relaxor transition temperature upon Zn‐doping was accompanied by a shift of the MPB toward the Na1/2Bi1/2TiO3‐rich side of the phase diagram. Higher tetragonal phase fraction and increased tetragonal distortion were noted for Zn‐doped (1 – x)Na1/2Bi1/2TiO3‐xBaTiO3. In addition, ferroelectric hardening and the presence of an internal bias field (Ebias) were observed for all doped compositions. The piezoelectric constant d33 and the coupling coefficient kp decreased by up to ∼30%, while a 4‐ to 6‐fold increase in Qm was observed for the doped compositions. Apart from establishing a structure–property correlation, these results highlight the chemically induced shift of the phase diagram upon doping, which is a crucial factor in material selection for optimal performance and commercialization. [ABSTRACT FROM AUTHOR]

Temperature dependent X-ray powder diffraction and dielectric studies have been carried out on tetragonal compositions of (1− x) PbTiO3-( x) BiMeO3; Me = Sc and Zn1/2 Ti1/2. The cubic and the tetragonal phases coexist over more than 100°C for 0.70 PbTiO3-0.3 Bi( Zn1/2 Ti1/2) O3 and 0.66 PbTiO3-0.34 BiScO3. The wide temperature range of phase coexistence is shown to be an intrinsic feature of the system, and is attributed to the increase in the degree of the covalent character of the ( Pb + Bi)- O bond with increasing concentration of Bi at the Pb-site. The d-values of the {111} planes of the coexisting phases are nearly identical, suggesting this plane to be the invariant plane for the martensitic type cubic-tetragonal transformation occurring in these systems. [ABSTRACT FROM AUTHOR]

Temperature dependent X-ray powder diffraction and dielectric studies have been carried out on tetragonal compositions of (1− x) PbTiO3-( x) BiMeO3; Me = Sc and Zn1/2 Ti1/2. The cubic and the tetragonal phases coexist over more than 100°C for 0.70 PbTiO3-0.3 Bi( Zn1/2 Ti1/2) O3 and 0.66 PbTiO3-0.34 BiScO3. The wide temperature range of phase coexistence is shown to be an intrinsic feature of the system, and is attributed to the increase in the degree of the covalent character of the ( Pb + Bi)- O bond with increasing concentration of Bi at the Pb-site. The d-values of the {111} planes of the coexisting phases are nearly identical, suggesting this plane to be the invariant plane for the martensitic type cubic-tetragonal transformation occurring in these systems. [ABSTRACT FROM AUTHOR]