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Ternary system piezoelectric ceramics 0.7PbZrxTi1−xO3-0.3Pb(Zn1/3Nb2/3)O3 (abbreviated as 0.7PZTx-0.3PZN) were prepared by a traditional solid-phase process. With the increase in Zr content, the electrical properties of the ceramics were significantly improved, and this result could be attributed to the change in the ceramic phase structure. The relationship between the change in Zr content and the ceramic phase structure and properties was investigated in detail by component modulation. X-ray diffraction (XRD) analyses showed that the phase structure of the ceramics undergoes a transition from the coexistence of tetragonal (T) and rhombohedral (R) phases to the predominance of rhombohedral (R) phases as the Zr content x increases. The phase structure of the ceramics at x = 0.49 is closer to the morphotropic phase boundary (MPB), with about 32% of the T-phase and 68% of the R-phase, and possesses good electrical properties: d33 = 483 pC/N, kp = 0.69, εr = 2171.7, tanδ = 0.016, Tc = 292.5°C, Pr = 35.9 μC/cm2, Ec = 7.7 kV/mm. Constructing the MPB of 0.7PZT-0.3PZN piezoelectric ceramics by varying the Zr content can be effective in improving the electrical properties and understanding more broadly how the change in Zr/Ti composition affects the piezoelectric behavior. [ABSTRACT FROM AUTHOR]

xPb(Zn1/3Nb2/3)O3–(1−x)Pb(Zr0.52Ti0.48)O3 (xPZN–PZT) ternary piezoelectric ceramics with different PZN content were prepared by the traditional solid-state reaction method. The effect of relaxor ferroelectric PZN content on the phase structure, dielectric, piezoelectric and ferroelectric properties of xPZN–PZT ceramics has been systematically investigated. The XRD and SEM analysis results showed a slight increase in grain size with the increase in PZN content. The 0.2PZN–PZT ceramic samples have good grain size and exhibit the optimum properties: Tc = 318 °C, d33 = 347 pC/N, kp = 0.617, εr = 1232, tanδ = 3.0%, Pr = 37.9 µC/cm2, Ec = 6.6 kV/mm, respectively. Furthermore, all these results suggest that 0.2PZN–PZT can maintain a balance between the Curie temperature and piezoelectric properties. That is, it still has optimum electrical properties at high Curie temperatures. Enhanced piezoelectric ceramics properties could be attributed to its dielectric relaxor behavior. [ABSTRACT FROM AUTHOR]

Ba0.85Ca0.15Zr0.1Ti0.9O3-x wt% CuO (BCZT-xCu) lead-free piezoelectric ceramics were designed and synthesized using a traditional solid-state reaction method to improve both the relaxor behavior and the electrical properties of BCZT lead-free piezoelectric ceramics. The Cu2+ diffuses into the BCZT lattice and forms ABO3 perovskite solid solution. Additionally, X-ray diffraction patterns and Raman spectra reveal that the introduction of CuO causes phase transition from the O-T phase coexistence to the O phase in BCZT-xCu. SEM displays that BCZT-xCu has a well microstructure at CuO doping amount between 0.5 wt% and 1 wt%. With the increasing CuO content, the orthorhombic-tetragonal (TO-T) phase transition shifted towards higher temperature, while Curie temperature (Tc) shifted towards lower temperature. Moreover, the dielectric diffusivity γ increases from 1.63 to 1.92 as x increases. Results indicate that optimal electrical properties, namely d33 = 315 pC/N, kp = 34%, εr = 3213, tanδ = 2.71%, Pr = 7.45 µC/cm2 and Ec = 2.75 kV/cm are achieved in the 1 wt% CuO added ceramic sintered at 1250°C for 2 h. [ABSTRACT FROM AUTHOR]

BaTiO nanoparticles were prepared for the first time employing a solvothermal process from the synthetic precursors of KTiO nano-whiskers. The obtained samples were characterized by X-ray diffraction, transmission electron microscopy, selected area electron diffraction, and high-resolution transmission electron microscopy, etc. The results indicate that well-crystallized single-phase BaTiO nanoparticles are synthesized using KTiO as precursors under solvothermal conditions at as low as 0.9 M. The solvothermal method facilitates the crystallinity and formation of the BaTiO nanoparticles. However, the K ions cannot be completely replaced by Ba by the hydrothermal method even at 10 M due to its unique and extremely stable 'tunnel' structure. The solvothermal method provides new avenues for the ion-exchange synthesis of a variety of other perovskite-type materials such as MTiO (M = Pb, Sr, Ca, etc.). [ABSTRACT FROM AUTHOR]

0.55BaSrTiO-0.45MgO composite ceramics (BST-MgO, x = 0.5-0.65) co-modified with CuO and MnO were prepared by conventional soild state reaction method. The microstructure, phase and morphology were investigated. The results showed the formation of the perovskite BST phase and MgO phase. The dielectric constant ( ε) and tunability ( T) of the ceramic samples increased with increasing Ba content. The dielectric loss (tan δ) and figure of merit achieved their minimum and maximum at x = 0.6, respectively. The obtained ceramic sample with x = 0.6 exhibited favorable properties, which are listed as follows: ε = 190, tan δ = 0.22 %, T = 16 %, E = 5.6 kV/cm and FOM = 72.7. [ABSTRACT FROM AUTHOR]

Ceramics in PMN-PZT system with formula xPb(MgNb)O-(1 − x)Pb(ZrTi)O (where x = 0.32, 0.35, 0.38, 0.41) were prepared by the conventional oxide-mixed method. The phase diagram, composition dependent ferroelectric, dielectric, field-induced strain and piezoelectric properties were systematically investigated. X-ray diffraction analysis indicated that as-prepared ceramics were of pure perovskite phase and the possible morphotropic phase boundary (MPB) between the tetragonal and pseudo-cubic phase compositions were located near the PMN content of x = 0.38, confirmed by their corresponding ferroelectric, dielectric, field-induced strain and piezoelectric properties. The composition with x = 0.38 possessed the optimum electrical properties since its composition locate close to the MPB where exist multiple polarization directions facilitates domain reorientation and consequently enables the superior electrical properties. The room temperature dielectric permittivity ε, tangent loss tan δ, piezoelectric coefficient d, electromechanical coupling factor kp, remnant polarization P, hysteresis loop squareness R and longitudinal strain of 0.38PMN-0.62PZT ceramics are 2441, 2.08 %, 662 pC/N, 63.5 %, 37.2 μC/cm, 1.51 and 1.9 ‰, respectively, which mean it has a great promise for actuator applications. [ABSTRACT FROM AUTHOR]

0.55Pb(NiNb)O-0.135PbZrO-0.315PbTiO (PNN-PZ-PT) ternary piezoelectric ceramics with excess 1.0 wt.% PbO were synthesized by the conventional solid-state reaction method at 1175-1300 °C for 2 h, respectively. The influence of sintering temperature ( T) on microstructure, piezoelectric, dielectric, and ferroelectric properties were systematically investigated. The results of XRD and Raman scattering spectra demonstrated that a typical perovskite structure with mainly rhombohedral symmetry near the MPB region were obtained for all the samples. The tetragonal phase content was increased slightly with the increase of sintering temperature. In addition, with increasing T the average grain size increases while the density decreases were also found. The results of electrical measurements confirmed that piezoelectric constant, dielectric constant, remnant polarization were firstly increased and then decreased with the increase of sintering temperature. The optimum and remarkable enhanced electrical properties of d = 1070 pC/N, k = 0.69, ε = 8710, tanδ = 0.026, P = 24.08 μC/cm, and E = 3.2 kV/cm were obtained for the sample sintered at 1250 °C for 2 h. Meanwhile, the sample exhibits a typical relaxor ferroelectric behavior with the maximum dielectric constant ε =24541 at Curie temperature T = 113.3 °C at 1 kHz. [ABSTRACT FROM AUTHOR]

KNaNbO- x ZnO (KNN- xZn) lead-free ceramics have been prepared using the conventional sintering technique and the effects of ZnO addition on the phase structure and piezoelectric properties of the ceramics have been studied. Our results reveal that a small amount of ZnO can improve the density of the ceramics effectively. Because of the high density and ZnO doping effects, the piezoelectric and dielectric properties of the ceramics are improved considerably. The good piezoelectric and dielectric properties of d = 114 pC/N, k = 0.36, ε = 395, and Q = 68 were obtained for the KNN ceramics doped with 1 mol% ZnO. Therefore, the KNN-1.0 mol%Zn ceramics is a good candidate for lead-free piezoelectric application. [ABSTRACT FROM AUTHOR]

Zirconia ceramics are widely used in aerospace, precision machinery, electronics, and biomedical fields because of their high temperature resistance, wear resistance, strong electromagnetic response, and biocompatibility. Nevertheless, high brittleness and low shear strength seriously hinder the large-scale application of zirconia ceramics in industrial production. This paper mainly reviews the research advances on primary machining technologies of zirconia ceramics from two aspects. One aspect is traditional machining of zirconia ceramics, which primarily focuses on the issues such as tool wear, machined surface quality, and cutting force in milling and grinding of zirconia ceramics. And the other aspect is non-traditional machining of zirconia ceramics, which primarily focuses on material removal rate and machined surface quality of zirconia ceramics using the electrical discharge machining (EDM) by assisting electrode method. The machinability and machining quality of zirconia composite ceramics by EDM with the adding conductive phase method have also been analyzed. Furthermore, for the auxiliary machining methods, the effects of ultrasonic vibration-assisted machining (UVAM) and laser-assisted machining (LAM) of zirconia ceramics are comparatively analyzed and elaborated. Subsequently, the research progress of traditional and non-traditional machining of zirconia ceramics is summarized and discussed. Finally, different machining methods of zirconia ceramics were prospected, and their future development trends were discussed, which provides a reference for further improving the machining efficiency and accuracy of zirconia ceramics. [ABSTRACT FROM AUTHOR]