10 results about "Relaxor ferroelectric" patented technology

The application discloses a self-supporting structure deep water transducer based on a relaxor ferroelectric single crystal, which comprises a certain number of transducer units, each of which comprises a piezoelectric element, a transition block, a curved shell, a force transmission plate and a radiation panel; the piezoelectric element adopts a relaxor ferroelectric single crystal element; the curved shell adopts a type VII bending-stretching transducer shell form with the long axis and the short axis vibrating in phase, one force transmission plate is added to the outside of the short axis of the shell, a certain number of transducer units are arranged in a certain rule, the radiation panel is connected to the transducer units through the force transmission plates at both ends of the transducer units, the transverse vibration of the single crystal element is amplified in displacement through the curved shell at the short axis of the shell, the vibration is transmitted to the radiation panel through the force transmission plate, the radiation panel is used for reducing the working frequency, unifying the vibration phase of the transducer units, directly facing the fluid to bear the hydrostatic pressure, and isolating the internal space from the external fluid; the static pressure of the external fluid acts on the radiation panel and then acts on the short axis of the shell through the force transmission plate.

The application discloses layered composite lead-free relaxor ferroelectric material and a preparation method thereof, and belongs to the technical field of piezoelectric ceramics, and overcomes the defects that the strain excited by the lead-free relaxor ferroelectric material in the prior art is small under a low driving electric field. The layered composite lead-free relaxor ferroelectric material comprises a first relaxor ferroelectric layer, a ferroelectric layer and a second relaxor ferroelectric layer arranged in sequence; and in the layered composite lead-free relaxor ferroelectric material, 0 < ferroelectric layer mass percentage < 30%. The application provides the layered composite lead-free relaxor ferroelectric material which has low driving electric field and large strain.

The application relates to the technical field of inorganic nonmetal functional ceramic materials, and discloses a polar vortex structure relaxor ferroelectric ceramic material and a preparation method and application thereof, the material is of a chemical formula (1-x)(0.7NaNbO3-0.3Sr 0.7 Bi 0.2 TiO3)-xCaSnO3, wherein 0<=x<=0.2, and a characteristic value is x=0.1. By adopting a step-by-step solid-phase reaction method, NaNbO3, Sr 0.7 Bi 0.2 TiO3 and CaSnO3 ceramic powders are pre-synthesized, then are ball-milled according to a stoichiometric ratio and are sintered into ceramics. The prepared ceramic material has a multi-phase coexistence, core-shell and polar vortex structure, and exhibits high saturation polarization intensity, low hysteresis, large breakdown field strength and excellent service stability, and has potential application in high-power pulse devices. The material is environment-friendly and simple in process, and is expected to provide a new technical path for design and preparation of high-performance and high-stability nonlinear dielectric energy storage materials.

This invention discloses a method for establishing a phase-field model of a polycrystalline phase relaxor ferroelectric, the method comprising the following steps: 1. Determining the free energy of the polycrystalline phase relaxor ferroelectric; 2. Determining the order parameter of the polycrystalline phase relaxor ferroelectric as spontaneous polarization. P i 3. Represent free energy as spontaneous polarization P i The invention employs several methods: 1) introducing ferroelectric-ferroelectric phase boundaries and random local electric fields; 2) solving the Ginzburg-Landau partial differential equations to obtain the spatial evolution of spontaneous polarization, thereby determining the domain structure of polycrystalline relaxed ferroelectrics and ultimately establishing a phase-field model for polycrystalline relaxed ferroelectrics. Based on a model ferroelectric system, this invention, by considering ferroelectric-ferroelectric phase boundaries and random local electric fields, reproduces the unique domain structure characteristics of polycrystalline relaxed ferroelectrics with the coexistence of multiple nanometer-sized ferroelectric phases, establishes a phase-field model for polycrystalline relaxed ferroelectrics, and improves the theoretical model of polycrystalline relaxed ferroelectrics, which is beneficial for guiding the design of novel high-performance ferroelectric materials.

This invention relates to the field of relaxor ferroelectric ceramic dielectric energy storage materials, specifically to a sodium bismuth titanate-based relaxor ferroelectric ceramic and its preparation method, wherein the chemical composition of the sodium bismuth titanate-based relaxor ferroelectric ceramic is (1-x)BNLT. ‑x BAN, of which BNLT is 0.9Bi 0.5 Na 0.5 TiO3-0.1Bi 0.5 Li 0.5 TiO3, BAN is BaAl 0.5 Nb 0.5 The value of O3 and x ranges from 0.06 to 0.18. When x = 0.15, the ceramic exhibits excellent performance with a recoverable energy storage density (Wrec) of not less than 14.0 J / cm³ and an energy storage efficiency (η) of not less than 84% under an electric field of 775 kV / cm. This invention employs a solid-state reaction sintering process, which is simple to prepare and low in cost, making it suitable for high-performance energy storage capacitors in pulsed power systems.

This invention relates to the field of dielectric energy storage ceramic materials, specifically to a CaTiO3-based relaxor ferroelectric ceramic material and its preparation method. The general chemical formula of the CaTiO3-based composite relaxor ferroelectric ceramic material is: (1-x)Ca 0.5 Bi 0.25 Na 0.25 TiO3-xBaZrO3, where 0 < x ≤ 0.30, is produced by solid-state reaction method, in which Bi2O3, Na2CO3, CaCO3, TiO2, BaCO3, and ZrO2 are stoichiometrically proportioned, followed by wet ball milling, pre-calcination, granulation, tableting, debinding, and sintering. This invention, by constructing a relaxor ferroelectric heterojunction, synergistically optimizes the breakdown field strength, polarization intensity, and dielectric loss, solving the problems of polarization saturation and low energy storage efficiency in traditional ferroelectrics.

This invention discloses an A-site doped lead-free ceramic material, its preparation method, and its applications, relating to the field of dielectric ceramics technology. This invention simultaneously introduces multiple cations such as Sr, Ca, Bi, and Na into the A-site (Ba) of a barium titanate (BaTiO3) matrix to construct a high-entropy doped structure, effectively controlling lattice distortion and local polarization behavior, thereby obtaining excellent relaxor ferroelectric properties and high breakdown field strength. The material is prepared using an electrospinning combined with heat treatment process to form a nanofiber structure with a beaded morphology, significantly inhibiting abnormal grain growth, increasing density, and reducing defect concentration. The resulting ceramic exhibits high energy density, high energy storage efficiency, and excellent cycle stability over a wide temperature range. It is also free of toxic elements such as lead, making it environmentally friendly and suitable for high-temperature, high-power electronic devices in new energy vehicles, 5G communications, aerospace, and other fields, providing a reliable technical solution for developing next-generation high-performance lead-free energy storage capacitors.

The application discloses a high-performance relaxor ferroelectric single crystal and a preparation method and application thereof, and belongs to the technical field of piezoelectric materials. Based on a TSSG method, through the synergistic effect of a bottom oxygen feeding technology and component regulation, a technical problem that a piezoelectric charge coefficient d 33 and a piezoelectric voltage coefficient g 33 are difficult to be considered simultaneously in the existing relaxor ferroelectric single crystal is successfully solved. The bottom oxygen feeding technology effectively inhibits Pb element volatilization and compensates oxygen vacancies, greatly reduces the defect density and the content of impurities in the crystal, and eliminates the pinning effect of defect dipoles on domain switching. In combination with accurate construction of a morphotropic phase boundary, the single crystal can fully release the polarization deflection advantage caused by the coexistence of multiple phases. The prepared PYN-PMN-PT relaxor ferroelectric single crystal realizes the coexistence of high piezoelectric response and excellent piezoelectric voltage coefficient, and significantly improves the quality factor of the material.

The application discloses a sodium bismuth titanate-based relaxor ferroelectric material with high electro-strain, low hysteresis and high temperature stability and a preparation method thereof, and belongs to the technical field of functional materials. (0.47‑x) Li x / 2 K x / 2 Bi 0.47 Ba 0.06 TiO3, wherein 0.06<=x<=0.10. The material has high electro-strain, low hysteresis and high temperature stability, and is suitable for micro displacement devices. The preparation method comprises the following steps: weighing raw materials according to stoichiometric ratios, ball milling, drying, grinding, calcining, ball milling again, drying and grinding again; adding a binder to granulate and sinter to obtain ceramic sheets; and polishing the ceramic sheets and electroplating silver on surfaces of the ceramic sheets. The method is simple, low in cost and suitable for large-scale production.