56results about How to "Lower coercive field" patented technology

The polycomponent lead-free piezoelectric ceramic composition with excellent performance is one perovskite type environment consistency piezoelectric ceramic composition. The composition has the general expression of (1-e-f-g)(Bi1-uLu)1-w(Na1-x-yKxLiy)wTiO3+eBaTiO3+fSrTiO3+gCaTiO3+aMalphaObeta, where x is 0-1, y 0-0.5, u 0-0.12, (x+y) 0-1, e 0-1, f 0-1, g 0-1, (e+f+g) 0-1, w 0.3-0.7, L is RE elements La, Ce, Pr, Nd, Sm, etc.; MalphaObeta is doping oxide(s) in the content an of 0-10 %; M is +1~+6 valent element capable of forming solid oxide, such as Na, K, Li, Zn, Cr, etc. with alpha and beta being atom number. The piezoelectric ceramic composition has d33 up to 200 pC/N, kp up to 36.0 % and stable technological process, may be produced via traditional piezoelectric ceramic preparation process and industrial material, and is practical.

This invention discloses a method for preparing highly (111)-oriented PZT thin film. The method can solve the problems of complex process and low repeatability faced by sol-gel method. The method comprises: preparing PZT sol, depositing PZT thin film, pre-crystallizing PZT thin film, and crystallizing PZT thin film. The method is simple. The obtained PZT thin film has compact and smooth surface, uniform thickness, uniform grain sizes, high residual polarization value (43-60 muC/cm2), low coercive field (60-75 kV/cm), and high saturated polarization value.

The lead-free bismuth sodium lithium barium strontium titanate piezoelectric ceramic is one polycomponent perovskite type environment consistency piezoelectric ceramic composition. The composition has the general expression of (1-y-z-u)Bi1-w(Na1-xLix)wTiO3+yBaTiO3+zSrTiO3+uCaTiO3+aMalphaObeta, where x is 0-0.5, y 0-1, z 0-1, u 0-1, (y+z+u) 0-1, w 0.3-0.7; MalphaObeta is doping oxide(s) in the content an of 0-10 %; M is +1~+6 valent element capable of forming solid oxide, such as Na, K, Li, Ni, Zn, etc. with alpha and beta being atom number. The piezoelectric ceramic composition has d33 up to 200 pC/N, kp up to 35.0 % and stable technological process, may be produced via traditional piezoelectric ceramic preparation process and industrial material, and is practical.

The invention relates to lead-free piezoelectric ceramic and a preparation method thereof. The problems that the production technology is complex, sintering is difficult, piezoelectric ceramic is poor in performance and requirements in actual application are not met are solved. The method includes the steps that BaCO3 powder, ZrO2 powder and TiO2 powder are contained in a ball milling tank, ethyl alcohol is added to be ground, dried, tabletted and pre-sintered to synthesize BaZr0.055Ti0.945O3; ethyl alcohol is added to Bi2O3, Na2CO3, TiO2, MnO2 and BaZr0.055Ti0.945O3 to be ball-milled and dried, an adhesive is added, compaction and plastic removal are conducted, the mixture is buried with powder to be sintered, silver paste coating and forging are conducted, and a silver electrode is formed on the surface; then the product is placed in silicon oil, the electric field is polarized, and the lead-free piezoelectric ceramic material is obtained. The Mn-codoped Bi0.5Na0.5TiO3-BaZr0.055Ti0.945O3 lead-free piezoelectric ceramic is designed and synthesized for the first time, the coercive field and leakage current of piezoelectric ceramic are effectively reduced, polarizability is improved, performance is good, the method is simple, and production and preparation are easy.

The invention relates to a preparation method of potassium sodium niobate based piezoelectric ceramics, and belongs to the field of novel lead-free based functional ceramics. The method is characterized in that the solid solubility between potassium niobate and sodium niobate in the potassium sodium niobate based piezoelectric ceramics is increased to improve the electric properties of the potassium sodium niobate based piezoelectric ceramics; and the potassium sodium niobate based piezoelectric ceramics comprise the following raw materials in mol percentage: 48-52% of K2CO3, 48-52% of Na2CO3, 96-100% of Nb2O5 and 0-4% of Sb2O3. The method provided by the invention can effectively regulate and control the phase structure and the microscopic morphology of the potassium sodium niobate based piezoelectric ceramics, thereby improving the electric properties of the potassium sodium niobate based piezoelectric ceramics.

The invention discloses a high Curie temperature lead-free SNKBT piezoelectric ceramic with a chemical formula of Sr0.9(Na0.5-xKxBi0.5)0.1Bi4Ti4O15, wherein x equals o 0.12-0.32wt.%. The method comprises the steps of: preparing ingredients of Na2CO3, K2CO3, SrCO3, material TiO2, and Bi2O3 according to their stoichiometric ratio, carrying out ball milling for 4h, drying, sieving, and synthesizing at 850 DEG C; then conducting secondary ball milling, drying, sieving, and adding 7wt.% of PVA water solution for granulation, and molding into a blank; discharging rubber, sintering the blank at 1100 DEG C for, then coating a layer of silver on the upper and lower surfaces of the piezoelectric ceramic, carrying out sintering permeation, and polarizing in silicone oil of 170 DEG C under the electric field strength of 10KV / mm for 5-10min so as to produce the high Curie temperature lead-free SNKBT piezoelectric ceramic. The invention overcomes the shortcomings of doping of other elements and large amount of replacement to obtain high voltage characteristic in the preparation process; and the system reduces the coercive field and low voltage characteristic of the electrical ceramic caused by inadequate polarization, improves the preparation process, and improves the piezoelectric properties.

The invention relates to a ferro-electricity film capacitor of ferro-electricity and relative preparation, wherein said film capacitor is formed by silicon substrate, silica dioxide baffle layer, titania adhesive layer, low electrode metal layer, low buffer layer, ferro-electricity film layer, up buffer layer, and up electrode metal layer; the adhesive layer is 10-30nm thick; the low electrode metal layer is 100nm-300nm; the low buffer layer is 5-20nm thick; the ferro-electricity is 200-500nm thick; the up buffer layer is 100-200nm thick; the up electrode metal layer is 80-150nm thick. The inventive capacitor has low fatigue speed, low drain current. The invention uses magnetic control splash method to layer-to-layer splash production, while the product has better property, with single direction.

The invention discloses a multiferroic liquid. The multiferroic liquid is a stable suspension liquid obtained by uniform dispersion of multiferroic nano-particles in a uniform mixed solution of a base liquid and a surfactant. The preparation method of the multiferroic liquid comprises pouring dry multiferroic nano-particles into a mixed solution of a base liquid and a surfactant in a container, sealing the container, putting the sealed container into a shaking table and carrying out shaking to obtain a stable multiferroic liquid. Compared with the solid multiferroic material, the multiferroic liquid has ferroelectricity, magnetism, fluidity, unique magneto-optic effect and optical direfringence effect, electric field (magnetic field) sensibility, and strong magnetoelectric effect. Through application of a small electric field (magnetic field), ferroelectricity and magnetism of the multiferroic liquid can be adjusted and controlled. Multiferroic nano-particles of the multiferroic liquid can easily rotate in the electric field (magnetic field) so that an electric domain direction is completely along an electric field direction. The multiferroic liquid provides a novel research direction of a multiferroic material and has a good application prospect.

The invention relates to a B-site Mn and Cu codoped high remanent polarization BiFeO3 film and a preparation method, the method comprises the following steps: dissolving bismuth nitrate, ferric nitrate, manganese acetate and cupric nitrate according to mol ratio of 1.05: [(0.92-0.98)-x]: (0.02-0.08):x in a mixed liquor of ethylene glycol monomethyl ether and acetic anhydride, then uniformly stirring to obtain a BiFeO3 precursor; wherein total metal ion concentration of the BiFeO3 precursor is 0.1-0.5mol/L, X is 0.01-0.03; performing spin coating of the BiFeO3 precursor on a FTO/glass substrate to prepare a wet membrane, baking the wet membrane to obtain a dry membrane, then annealing at 550 DEG C to obtain the crystalline state BiFeO3 film; cooling the crystalline state BiFeO3 film, and repeatedly making the crystalline state BiFeO3 film to reach a required thickness to obtain the B-site Mn and Cu codoped high remanent polarization BiFeO3 film. According to the invention, a sol gel technology is employed, the equipment requirement is simple, the film is prepared on large surface and surfaces with irregular shapes, the chemical component is accurate and controllable, and the regulation and control to its crystal structure can be carried out by codoping thereby the ferroelectric performance of the film is greatly increased.

The invention relates to a method for forming an optical waveguide quantum chip on gradual periodically polarized lithium tantalate by a proton exchange method, and belongs to the field of optoelectronic device preparation methods. The method comprises the following steps: a gradual periodically polarized lithium tantalate is cleaned; a titanium film and a chromium film are sequentially plated on the surface of the substrate; a mask sample for proton exchange is form by performing ultraviolet light etching on the surface of the chromium film; the obtained sample is subjected to proton exchange at 200-300 DEG C so as to form a strip optical waveguide; the two end surfaces perpendicular to the optical waveguide are optically ground and polished; the optical waveguide performance of the waveguide is tested by a light passing experiment; and the two polished end surfaces are coupled by optical fiber end surfaces and cured by UV glue, and the two ends of the optical fiber jumper are used as input and output ends respectively so as to prepare the optical quantum chip. The optical waveguide chip with high performance, low transmission loss, micron scale and good crystal nonlinearity can be prepared and the crystal nonlinearity tuning range is wide.

The invention discloses a lead-free ceramic dielectric material with high field-induced strain and high energy storage density. The composition is represented as a general formula: [(Bi0.95La0.05)0.5Na0.5](1-x-y)(Bi0.5K0.5)x(Ba0.85Sr0.10Mg0.05)yTi(1-u-v)Cu(A(1/2)B(1/2))vO3, wherein A represents a trivalent metal element and is selected from one or two of Al, Fe, Cr, Mn, Co, Y and Ga; B represents a pentavalent metal element and is selected from one or two of Nb, Sb, Ta and V; C represents a tetravalent metal element and is selected from one of Zr, Mn, Hf and Sn; x, y, u and v represent mole fraction, x is larger than or equal to 0.005 and smaller than or equal to 0.2, y is larger than or equal to 0.005 and smaller than or equal to 0.2, the sum of x and y is smaller than or equal to 0.3, u is larger than or equal to 0.005 and smaller than or equal to 0.3, v is larger than or equal to 0.005 and smaller than or equal to 0.3, and the sum of u and v is smaller than or equal to 0.4. Cold isostatic pressing is adopted, uniform and compact ceramic texture can be acquired, and a preparation process is simple, stable and suitable for industrial popularization and application; the ceramic with high field-induced strain and high energy storage density has excellent energy storage density, energy storage efficiency and high-field strain, the energy storage density can be 1.2 J/cm<3>, the energy storage efficiency can be 59%, the high-field strain can be 0.28%, and the ceramic is environment-friendly, low in energy consumption and good in practicability.

The invention relates to a ferrite soft magnetic material and provides an inverse spinel zinc ferrite with high saturation magnetic susceptibility, resistivity, Curie temperature and resistance, a low coercive field and excellent properties and a preparation method thereof. The inverse spinel zinc ferrite has a chemical formula of ZnFe2O4 and a structural formula of (Zn0.5Fe0.5)[Zn0.5Fe1.5]O4. The preparation method comprises the following steps: mixing zinc sulfate hetahydrate with ferric sulfate and adding lithium chloride so as to obtain a mixture of zinc sulfate hetahydrate, ferric sulfate and lithium chloride; putting the mixture in a high temperature furnace for reaction; cooling and rinsing a resultant; dispersing the resultant in ethanol and separating magnetic products with a magnet so as to obtain zinc ferrite powder; and carrying out compression molding on the zinc ferrite powder with a binder after ball milling so as to obtain the inverse spinel zinc ferrite.

The invention provides a Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film and a preparation method thereof. The method comprises the following steps: preparing a Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 precursor solution from bismuth nitrate, praseodymium nitrate, hydrogen nitrate AE, ferric nitrate and manganous nitrate, wherein AE is Sr, Ca or Ba, and x=0.02-0.05; spinning the precursor solution on a substrate; and then spinning, drying and annealing, so as to obtain the Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film. The Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film is simple in demands on equipment; the experiment condition is easy to achieve; the doping amount is easy to control; the ferroelectric property of the film can be greatly improved; and the prepared Bi[0.85-x]Pr0.15AExFe0.97Mn0.03O3 ferroelectric film is good in uniformity, low in leakage current, and low in coercive field, and has relatively high remanent polarization.

The invention relates to a ceramic composite with a bismuth layer structure with good comprehensive performance in high-temperature piezoelectricity, dielectric and so on. The chemical formula of the ceramic composite is (Sr2-xCax)1-yMyBi4Ti5O18, wherein M can be one or more of Mn, Ba, Ce, Pb and other elements; x is more than or equal to 0 and is less than or equal to 2, and y is more than or equal to 0 and is less than or equal to 1. The composite has good performance when x is equal to 1 and y is equal to 0, and the Curie temperature is more than or equal to 570 DEG C. At room temperature, piezoelectric constant d33 is more than or equal to 22pC.N<-1>; d33 is more than 17pC.N<-1> at a temperature of 550 DEG C, and 80 percent of the piezoelectric activity is still maintained. From room temperature to 550 DEG C, the dielectric loss of the composite in 100 kHz is less than or equal to 0.07, and the dielectric loss of the composite in 1MHz is less than or equal to 0.02, and the specific inductive capacity-temperature coefficient is small. The ceramic composite can fulfill the application in steel, chemical engineering, energy, aerospace engineering and other industrial fields.

The invention provides a ternary nano leadless piezoelectric ceramic material. General chemical formula of the ternary nano leadless piezoelectric ceramic material is (1-x)Na<0.5>Bi<0.5>TiO<3>-xNa<0.5>Bi<0.5>NbO<3>+yM, wherein M is used for representing a metallic element, x and y are used for representing mass contents, and 0<x<1, 0.0005<y<0.01. The invention also provides a method used for preparing the ternary nano leadless piezoelectric ceramic material via sol-gel method. Compared with existing technology, the ternary nano leadless piezoelectric ceramic material prepared via the method is small in particle size, narrow in particle size distribution range, uniform in composition, and high in piezoelectric activity; induction of impurities is difficult to happen in grinding processes; purity is high; sintering temperature is low; energy is saved; and compactness of ceramic powder after sintering is excellent. The preparation method is simple; processes are stable; industrialized degree is high; economic benefits are excellent; and application value is high.

The invention provides a HoSrMnZn co-doped bismuth ferrite multiferroic film and a preparation method thereof. According to the invention, bismuth nitrate, holmium nitrate, strontium nitrate, ferric nitrate, manganese acetate and zinc nitrate are used as raw materials (wherein bismuth nitrate is 5% excess in amount), ethylene glycol monomethyl ether and acetic anhydride are used as solvents, and a spin-coating process and a layer-upon-layer annealing process are employed to prepare a Bi<0.89>Ho<0.08>Sr<0.03>Fe<0.97-x>Mn<0.03>Zn<x>O<3> multiferroic film, i.e., the HoSrMnZn co-doped bismuth ferrite multiferroic film. According to the invention, a sol-gel process is employed, and the spin-coating and layer-upon-layer annealing processes are utilized; requirements on equipment are simple; experimental conditions are easy to realize; the preparation method is suitable for preparation of films on large surfaces and surfaces with irregular shapes and allows chemical components to be accurate and controllable; and the prepared HoSrMnZn co-doped bismuth ferrite multiferroic film has good uniformity and improves the multiferroic performance of a BiFeO3 film.

The invention discloses a MnxGey crystal with an orthogonal structure and a preparation method of the MnxGey crystal, and belongs to the field of preparation and application of magnetic materials, and the cell parameter of the crystal is that the space group of the crystal is Cmmm. According to the preparation method, elemental metal elements manganese and germanium are used as raw materials, the orthorhombic-phase MnxGey single crystal is finally prepared through the technological processes of raw material mixing, briquetting, assembling, high-temperature and high-pressure synthesis and cooling pressure relief, x is 1-2, y is 8-9, the preparation method is simple, the preparation period is short, and it is proved that the MnxGey crystal is single-phase and free of impurities and twin crystals. In addition, the single crystal material has a small coercive field, can be used as a soft magnetic material for increasing the magnetic flux density in a weak magnetic field, has the Curie temperature up to 322K and the magnetization intensity up to 10-30emu/g, has the advantages of high initial magnetic conductivity and maximum magnetic conductivity, has technical parameters applied to the soft magnetic material, and is suitable for being applied to low-frequency electromagnetic elements.