New Bismuth Sodium Titanate Based Ceramics and Their Applications

Ferroelectric materials are widely investigated due to their excellent properties and versatile applications. At present, the dominant materials are lead-containing materials, such as Pb (Zr,Ti)O3 solid solutions. However, the use of lead gives rise to environmental concerns, which is the driving force for the development of alternative lead-free ferroelectric materials. (Bi0.5Na0.5)TiO3-based ceramics are considered to be one of the most promising lead-free materials to replace lead-containing ferroelectric ceramics due to their excellent ferroelectric properties, relaxation characteristics, and high Curie point. After decades of efforts, great progress has been made in the phase structure characterization and properties improvement of BNT based ceramics. However, most of the studies on BNT system mainly focuses on its piezoelectric properties and application of piezoelectric sensors and strain actuators, little attention is paid to its ferroelectric properties and related applications. In this chapter, new BNT-based ceramics via composition modification and special focuses on the ferroelectric properties, phase transition behaviors under external fields and related applications, such as application in energy storage, pulsed power supply and pyroelectric detection were proposed

E -tunable magnetic susceptibility and reversible magnetization switching in YIG/Pt/PMN-PZT/Pt heterostructure by low electric and magnetic fields

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Pressure driven depolarization behavior of Bi 0.5 Na 0.5 TiO 3 based lead-free ceramics

Pressure driven depolarization behavior has been widely investigated for its scientific significance and practical applications. However, previous related studies were all based on lead-containing ferroelectric (FE) materials leading to detrimental environmental concerns. In the present work, we report the pressure driven depolarization behavior in Bi-based lead-free 0.97[(1-x)Bi0.5Na0.5TiO3-xBiAlO3)]-0.03K0.5Na0.5NbO3 (BNT-x) ceramics. Particularly, with increasing hydrostatic pressure from 0 MPa to 495 MPa, the remanent polarization of BNT-0.04 decreases from 30.7 µC/cm2 to 8.2 µC/cm2, reducing &$8764;73% of its initial value. The observed depolarization phenomenon is associated with the pressure induced polar FE-nonpolar relaxor phase transition. The results reveal BNT based ceramics as promising lead free candidates for mechanical-electrical energy conversion applications based on the pressure driven depolarization behavior.This work was supported by Chinese Academy of Sciences Research Equipment Development Project (No. YZ201332), National Program on Key Basic Research Project (973 Program) (No. 2012CB619406), Shanghai International Science and Technology Cooperation Project (No. 13520700700), and international partnership project of Chinese Academy of Science. Zhen Liu also acknowledges the support of Shanghai Sailing Program (No. 17YF1429700)

Giant power output in lead-free ferroelectrics by shock-induced phase transition

The force-electric effect in ferroelectrics is characterized by the release of bound charge during pressure/shock-induced depolarization. In contrast to other electrical energy storage systems, the charge-storage/release by the force-electric effect of ferroelectrics is determined by polarization switching or polar-nonpolar phase transition. This offers a further set of options for materials design in the realm of energy conversion, especially for the high power density applications. Here, we report that a ferroelectric ceramic, N a 0.5 B i 0.5 Ti O 3 (NBT), can generate a high power output ( 3.04 × 10 8 W / kg ) under shock compression, which is one of the highest values achieved by the force-electric effect. The in situ synchrotron x-ray diffraction studies reveal that this power output mainly arises from a polar-nonpolar phase transition (rhombohedral-orthorhombic). First-principles calculations show that this is a first-order phase transition that undergoes two-step structure changes. These results extend the application of the force-electric effect and are a key step in understanding the phase transition behaviors of NBT under high pressure

Experimental Study on the Brittle-Ductile Response of a Heterogeneous Soft Coal Rock Mass under Multifactor Coupling

After a gas drainage event causes different degrees of initial porosity in the coal seam, the heterogeneity of the coal mass becomes much more obvious. In this paper, soft coal testing samples with different degrees of heterogeneity were prepared first by a new special experimental research method using hydrogen peroxide in an alkaline medium to generate oxygen. Then, a series of mechanical tests on the soft coal mass samples were carried out under multiple factor coupling conditions of different heterogeneities and confining pressures. The results show that with a low strength, the ductility failure characteristic and a kind of rheology similar to that for soft rock flow were reflected for the soft coal; i.e., the stress-strain curve of the coal mass had no apparent peak strain and residual strength. An interesting phenomenon was found in the test process: there was an upwardly convex critical phase, called the brittle-ductile failure transition critical phase, for the heterogeneous soft coal mass between the initial elastic compression phase and the ductile failure transition phase in the stress-strain curve of the coal mass. An evolution of the brittle-ductile modulus coefficient of the soft coal was developed to analyze the effect of the internal factor (degree of heterogeneity) and external factors (confining pressure) on the transition state of the brittle-ductile failure of soft coal. Further analysis shows that the internal factor (heterogeneity) was also one of the essential factors causing the brittle-ductile transition of soft coal

Electric field tunable thermal stability of energy storage properties of PLZST antiferroelectric ceramics

The electrical hysteresis behaviors and energy storage performance of Pb0.97La0.02(Zr0.58Sn0.335Ti0.085)O3 antiferroelectric (AFE) ceramics were studied under the combined effects of electric field and temperature. It was observed that the temperature dependence of recoverable energy density (Wre) of AFE ceramics depends critically on the applied electric field. While Wre at lower electric fields (8 kV/mm) demonstrates decreasing dependence. There exists an appropriate electric field (8 kV/mm) under which the AFE ceramics exhibit nearly temperature‐independent Wre (the variation is less than 0.5% per 10°C). The underlying physical principles were also discussed in this study. These results indicate that the temperature dependence of Wre of AFE materials can be tuned through selecting appropriate electric fields and provide an avenue to obtain thermal stable energy storage capacitors, which should be of great interest to modern energy storage community.National Nature Science Foundation of China, Grant/Award Number: No. 51202273; NSAF, Grant/Award Number: U1330128; Chinese Academy of Sciences Research Equipment Development Project, Grant/Award Number: No. YZ201332; Shanghai Sailing Program, Grant/Award Number: 17YF1429700

J. Appl. Phys.

The dynamic hysteresis of Nb-doped Pb(ZrxTi1-x)O-3 (PZT, 0.40 <= x <= 0.60) ceramics with different phase structures was investigated as functions of frequency f and electric field amplitude E-0. When E-0 grows over similar to 1.5 times of coercive field E-c, all the loops become well saturated and their scaling relations of hysteresis area < A > against f and E-0 can be expressed with an identical form as < A > proportional to f(0.01)E(0)(0.10) for either tetragonal phase or morphotropic phase, which is in good agreement with our previous result of rhombohedral PZT [Chen et al., J. Appl. Phys. 114, 244101 (2013)]. The results indicate that ferroelectrics with fairly distinct domain structures could have similar dynamic hysteresis and scaling behavior at high-E-0 region. (C) 2014 AIP Publishing LLC.The dynamic hysteresis of Nb-doped Pb(ZrxTi1-x)O-3 (PZT, 0.40 against f and E-0 can be expressed with an identical form as proportional to f(0.01)E(0)(0.10) for either tetragonal phase or morphotropic phase, which is in good agreement with our previous result of rhombohedral PZT [Chen et al., J. Appl. Phys. 114, 244101 (2013)]. The results indicate that ferroelectrics with fairly distinct domain structures could have similar dynamic hysteresis and scaling behavior at high-E-0 region. (C) 2014 AIP Publishing LLC

Identical scaling behavior of saturated dynamic hysteresis in rhombohedral lead zirconate titanate bulk ceramics

The scaling behaviors of dynamic hysteresis were investigated in serial rhombohedral Nb-doped Pb(Zr1-xTix)O-3 (PZT) bulk ceramics as a function of frequency (f) and field amplitude (E-0). Three distinct regions were plotted including linear loops, minor loops, and saturated loops with an increase of E-0. When the external fields were over similar to 1.5 times of coercive field (E-c), the scaling relations of saturated loops for these PZT ceramics could be expressed with an identical form as hysteresis area proportional to f(0.01)E(0)(0.10), which indicated that similar ferroelectric systems with different compositions could display a uniform scaling law under high-E-0 and low-f regions. (C) 2013 AIP Publishing LLC