14 results about "Ionic radius" patented technology

The invention provides piezoelectric ceramic which is obtained by replacing Bi < 3 + > in Bi4Ti3O12 with Nd < 3 + > and replacing Ti < 4 + > in Bi4Ti3O12 with W < 6 + >. The structural formula of the piezoelectric ceramic is Bi < 4-x > Nd < x > Ti < 2.925 > W < 0.075 > O < 12 >, wherein x is greater than or equal to 0.01 and less than or equal to 0.05. The invention also provides a preparation method and application of the piezoelectric ceramic. Nd < 3 + > with smaller ion radius is introduced to replace Bi < 3 + >, and W < 6 + > is combined to replace Ti < 4 + >, so that the crystal structure of the ceramic can be finely adjusted, and the electrical property of the ceramic can be improved. Nd doping has great influence on the microstructure and macroscopic performance of the ceramic. Preferably, when x is equal to 0.03, the piezoelectric ceramic with very high piezoelectric property and resistivity is obtained.

The invention discloses a medium-entropy high-temperature dielectric ceramic and a preparation method thereof, and belongs to the technical field of functional ceramics, the chemical general formula of the ceramic material is (RE1, RE2, RE3) 3Al5O12, RE1, RE2 and RE3 are three different trivalent rare earth ions, and the key characteristic is that the ion radiuses of the three rare earth ions respectively belong to a large range, a medium range and a small range. According to the design, controllable maximum lattice distortion is introduced, the ion and electron polarizability of the material is remarkably enhanced on the premise that a garnet single-phase structure is not damaged, so that the intrinsic dielectric constant of the material is improved, and the medium entropy design ensures excellent high-temperature phase stability and dielectric property temperature stability of the material. The prepared medium-entropy high-temperature dielectric wave-absorbing ceramic can work in a high-temperature environment of 0-800 DEG C, not only has the characteristics of low heat conductivity and high temperature resistance, but also has excellent wave-absorbing performance in an X wave band, the lowest reflection loss of the medium-entropy high-temperature dielectric wave-absorbing ceramic can reach-58 GHz, and the effective absorption bandwidth of the medium-entropy high-temperature dielectric wave-absorbing ceramic can reach 2.8 GHz.

The invention provides a two-dimensional CsxRb (1-x) PbBr3 single crystal nanosheet and a preparation method thereof. Aiming at the problems of volatility difference of CsBr and RbBr and mismatch of Cs < + > and Rb < + > ion radiuses, the invention develops a chemical vapor deposition process with partition temperature cooperative control and multi-parameter optimization, and realizes controllable preparation of high-quality single crystal nanosheets in a full-component range for the first time. The structure has a regular square shape, the transverse size reaches tens of microns, and the thickness is several nanometers. Under laser excitation, the PL spectrum of the sample proves the continuous adjustability of the components and band gaps. All the alloy nanosheets show excellent single-peak emission characteristics, the photoluminescence peak position of the alloy nanosheets can be continuously tuned to 525 nm (green light) of CsPbBr3 from 447 nm (blue light) of RbPbBr3, and it is indicated that the synthesized all-component alloy has extremely high crystal quality. The two-dimensional structure with precise and controllable energy band engineering shows a wide application prospect in the fields of basic physical research and high-performance nano optoelectronic devices.

The invention relates to a pulse power type ceramic capacitor with high breakdown field intensity, a high-entropy relaxation ceramic dielectric material for the pulse power type ceramic capacitor and a preparation method, the high-entropy relaxation ceramic dielectric material comprises the following chemical components: BaTiO3, (Ba0. 2Ca0. 2Sr0. 2Bi0. 2Li0. 2) (Me0. 1Ti0. 9) O3, Bi (In0. 2Fe0. 2Al0. 2Li0. 2Ta0. 2) O3, MnO2 and MgO, and Me is any one of Zr, Hf and Sn; according to the invention, an equimolar-ratio high-entropy component with relatively large ion radius difference is designed in combination with the electricity price conservation principle, and the entropy value of a ceramic configuration is increased to 1.6 R by an A-site disordered (Ba0. 2Ca0. 2Sr0. 2Bi0. 2Li0. 2) (Me0. 1Ti0. 9) O3 material component and a B-site disordered Bi (In0. 2Fe0. 2Al0. 2Li0. 2Ta0. 2) O3 material component; the high entropy of the A site and the B site enables the dielectric material to obtain excellent comprehensive performance such as high breakdown field strength and high stability.

The invention provides a method for reducing YBCO nanowire warping voltage through ion irradiation, and belongs to the technical field of single photon detection. According to the method, a focused ion beam (FIB) is adopted to carry out helium (He) ion beam local periodic irradiation, an extra pinning center is introduced into the ultrathin YBCO nanowire, the movement of vortex in the nanowire is limited, the distribution uniformity of vortex pinning points is improved, and the warping voltage before voltage jump of the YBCO nanowire can be effectively reduced; meanwhile, the ion radius of He ions is small, the diffusion range of the He ions in the ultra-thin YBCO nanowire is smaller, and the influence of ion diffusion on the superconducting performance of the ultra-thin YBCO nanowire can be effectively reduced.

An alumina composition contains alumina particles and oxide particles composed of an oxide other than alumina. The oxide particles are composed of an oxide that contains cations having an ionic radius in hexacoordination of 0.41-1.2Å. The cumulative 50% particle diameter D50 from the fine-particle side of the volume-based cumulative particle size distribution is 5.0 μm or less, and the D50 of the alumina particles is 0.40 μm or less.

A solid ion conductor compound represented by Formula 1, an electrochemical cell including the same, and a method of preparing the solid ion conductor compound. The solid ion conductor is a compound of Formula 1LiaMbZrcXdTe  Formula 1wherein in Formula 1, 1<a<3.5, 0<b<1.5, 0<c<1.5, 0<d<7, 0≤e<1, 0<b / d<0.03, and 0.05<c / d<0.18,M is at least one monovalent metal element other than lithium, andT is a metal element different from M, a transition metal element, a post-transition metal element, a metalloid element, or a combination thereof,wherein an ionic radius of M satisfies 90 pm<Mr≤180 pm, wherein Mr is an ionic radius of M, and X is at least one halogen.

A fluorophosphate glass which essentially contains P, Al, K, Cu, F, and R (R is one or more elements selected from among Li, Na, Rb, and Cs), has an Al < 3 + > content of 2-20% by mass, and has an expected value of an ion radius of an alkali metal component containing K and R of 80 picometers or more and less than 133 picometers.

The invention provides a novel rare earth doped high-entropy oxide hydrogen isotope permeation resistant coating and a preparation method thereof. The coating is composed of Al, Ti, Cr, Zr, O and at least one rare earth element, through design, the ion radius difference between metal cations is larger than or equal to 10%, the electronegativity difference between the metal cations is larger than or equal to 10%, the special 4f electron configuration of the rare earth element and the lattice distortion effect of a high-entropy system are introduced, and rich and diversified hydrogen isotope capture sites are constructed in the coating. The coating is prepared by adopting a sol-gel method and comprises the steps of preparing a liquid precursor, performing dip-coating to form a film, performing preheating treatment, performing repeated coating, performing final annealing and the like. The method is simple in process and controllable in component, and a compact and uniform amorphous composite structure can be formed at a relatively low temperature. The coating provided by the invention has excellent hydrogen isotope permeation resistance, has a permeation reduction factor (PRF) of more than 2000, and is suitable for nuclear fusion reactors, hydrogen energy storage and transportation equipment and other fields with extremely high hydrogen resistance requirements.

The invention relates to the technical field of solid electrolyte and electrochemical separation, in particular to a medium-entropy proton conductor electrolyte material and a preparation method and application thereof. The chemical formula of the medium-entropy proton conductor is BaCe < 0.65 > Zr < 0.07 > Y < 0.07 > Y < 0.07 > Ta < 0.07 > M < 0.07 > O < 3 > delta, M is one or more than two elements of Sm, Eu, Gd, Nd or Sc, and delta represents oxygen vacancy concentration. A medium-entropy solid solution is formed by introducing various B-site doping with different ion radiuses and electronegativity, so that remarkable lattice distortion and local disorder can be generated, oxygen hole ordering is inhibited, and proton embedding and migration channels are optimized; the result shows that the proton conductivity is remarkably improved, and the dynamic difference between hydrogen (H) and deuterium (D) in the migration process is amplified, so that high-selectivity hydrogen isotope separation is realized under PCEC electrolysis operation.

The application provides a praseodymium-yttrium co-doped M-type hexagonal ferrite material and a preparation method and application thereof. z Fe 12‑x‑ y Pr x Y y O 19 , wherein 0.05<=x<=2.0, 0.05<=y<=1.5, 0.9<=z<=1.4, and x / y>1 / 7. The praseodymium and yttrium are doped into the M-type hexagonal ferrite, the characteristics of variable valence and large ion radius of praseodymium are utilized, and the Fe-deficient 3+ and Sr-rich 2+ environments are combined, so that Pr 4+ is formed, thereby reducing the grain size and forming a polyhedral aggregate, and meanwhile, the praseodymium-yttrium doping forms multiple impurities, interfaces are formed between the impurities and the main phase, and the interface polarization is promoted. The conversion of Pr 3+ to Pr 4+ is beneficial to the formation of oxygen vacancies and Fe 2+ , thereby significantly improving the dielectric properties of the material and enhancing the microwave absorption performance, and the material can be applied as a wave-absorbing material.

A fluorophosphate glass essentially contains each component of P, Al, K, Cu, F, and R, where R is one or more selected from Li, Na, Rb, and Cs. A content of Al3+ is 2% to 20% in terms of mass %, and an expected value of an ionic radius of an alkali metal component composed of K and R is 80 pm to less than 133 pm.

The invention discloses an energy storage device and a preparation method thereof. The energy storage device includes a ceramic matrix material and at least two doped ions, the ceramic matrix material including a plurality of lattice sites. The at least two types of doped ions are doped at different crystal lattice sites, and the difference value between the ion radius of the at least two types of doped ions and the ion radius of Ti < 4 + > is at least 5 angstroms. Thus, doped ions can cause serious lattice distortion to a perovskite crystal structure, so that an original long-range ordered ferroelectric structure of a ceramic matrix is damaged, polar nano micro-regions (PNRs) are formed, and due to the fact that lattice distortion of different degrees exists in the PNRs, Curie temperatures of different PNRs are often different. Therefore, the dielectric frequency dispersion temperature peak of the ceramic formed by the doped ions and the ceramic matrix material is broadened and even disappears, and the dielectric bias stability of the BNT ceramic is improved, so that the energy storage temperature stability of the BNT ceramic is improved.

The invention discloses a method for improving frequency temperature stability of microwave dielectric ceramic. According to the method, copper molybdate (CuMoO4) is taken as a base material, and through an entropy engineering strategy, two or more metal ions with the radius and coordination number similar to those of Cu < 2 + > ions are introduced into the A site of CuMoO4 for multi-component co-doping. The invention aims to increase the configuration entropy of a system, optimize the lattice stability of the material and effectively inhibit lattice parameter fluctuation caused by temperature change, so that the resonant frequency temperature coefficient of the copper molybdate-based microwave dielectric ceramic material is optimized, and meanwhile, the excellent dielectric constant and high quality factor of the copper molybdate-based microwave dielectric ceramic material are maintained. The prepared material has a low dielectric constant, a high quality factor and excellent frequency temperature coefficient stability, is expected to be used as an ideal substrate material of low temperature co-fired ceramic (LTCC), and has a wide application prospect in the fields of integrated circuits, radio frequency components, electronic packaging and the like.