95results about How to "Adjustable dielectric constant" patented technology

The invention relates to a low-loss microwave dielectric ceramic material and a preparation method thereof, which belongs to the technical field of an electronic information functional material and device. The low-loss microwave dielectric ceramic material comprises a main crystal phase and additives, wherein the main crystal phase comprises MgTiO3, Mg2SiO4 and CaTiO3, and the main crystal phase contains little Mg2TiO4; the additives comprise MnO2, Co2O3, CeO2 and Nb2O5; the loss of the material is detected to be low (Qxf falls in the range of 65000 to 85000GHz), the dielectric constant is adjustable (between 9 and 20), the frequency temperature coefficient is stable (within +/-10ppm/DEG C), the machinability is good, and the application requirement of a microwave communication industry can be met. The preparation method is a solid-phase sintering method and has the characteristics of simplicity, environmental friendliness and low cost, and is easy to control.

The invention is applicable to the field of wave-absorbing materials, and provides a graphene/ferroferric oxide composite wave-absorbing material and a preparation method thereof. The preparation method comprises the following steps: preparing a graphene oxide dispersion solution, a FeCl2 solution and a FeCl3 solution; mixing the three solutions, and stirring at 80-120 DEG C for 2-3 hours to obtain a graphene oxide/Fe3O4 dispersion solution; carrying out vacuum drying on the graphene oxide/Fe3O4 dispersion solution to obtain a graphene oxide/Fe3O4 aerogel; and heating the graphene oxide/Fe3O4 aerogel to obtain a graphene/Fe3O4 aerogel, and carrying out mechanical pelleting on the graphene/Fe3O4 aerogel to obtain the graphene/Fe3O4 composite material, wherein the graphene/Fe3O4 composite material is in a lamellar laminated structure. The graphene/Fe3O4 composite wave-absorbing material can absorb electromagnetic waves rather than reflect electromagnetic waves due to the electromagnetic performance matching characteristic, thereby lowering the secondary pollution of electromagnetic waves to the environment.

The invention relates to the field of wave absorbing materials, in particular to a composite wave absorbing material and a preparation method thereof. The composite wave absorbing material is characterized in that the surface of each of MXene layers is coated with a ferrite, and the different MXene layers and the ferrites on the surfaces of all the layers jointly form a sandwich structure. The composite wave absorbing material and the preparation method thereof provided by the invention have the benefits that MXene is prepared by adopting a chemical etching process, the ferrites prepared by adopting a hydrothermal preparation process are compounded with the MXene so as to grow in situ on the surface of MXene powder, the degree of integration between the ferrites and the MXene powder is high, and the coating is uniform and compact; the prepared MXene/ferrite composite wave absorbing material with the sandwich structure is light in density, high in strength, adjustable in dielectric constant and excellent in wave absorbing performance. In addition, the preparation method is simple, used equipment is simple, the process is stable, the production efficiency is high, the cost is reduced, the compactness and the uniformity of the material are good.

This invention relates to a method for preparing ceramic material with a sintering temperature below 950 deg.C. The ceramic material is composed of Ba1-xSrxTiO3 (x = 0.2 -0.6) 75.0-95.0 wt. %, MgO 0.15-15 wt. %, B2O3 0-1.0 wt. %, Li2CO3 3.0-10.0 wt. %. The method utilizes MgO and B2O3-Li2O sintering aid to dope and modify BST ceramic material, and the obtained ceramic material has such advantages as adjustable dielectric constant (100-2000) and low sintering temperature (850-950 deg.C). The ceramic material can be used in LTCC technique and microwave adjustable devices.

A SiO2 nanotube modified polyimide hybridized film with adjustable dielectric constant is prepared through proportionally adding SiO2 nanotubes to the solution of coupling agent, stirring while reaction, adding ODA monomer, ultrasonic dispersing, stirring while adding PMDA monomer, in-situ polymerizing reaction, coating it on glass plate, drying in the air, putting it in oven, and thermal iminating.

The invention relates to a low-temperature co-fired ceramic dielectric material and a preparation method thereof. The LTCC dielectric material comprises an oxide dielectric material having a high sintering temperature and an oxide activator, and the LTCC dielectric material concretely comprises 1-20 wt% of the oxide activator, and the balance of the oxide dielectric material having the high sintering temperature; the oxide dielectric material with the high sintering temperature is an oxide of M, wherein M is at least one of Mg, Al, Ti, Ca, Zr, Nd, MgTi, MgAl, CaTi and NdAl; and the oxide activator comprises an oxide of A and an oxide of B, A is at least one of Zn, Cu, Mn, Sn, Fe, Co and Ni, B is at least one of V, Nb, Ta, Ti and Si, and the mass of the oxide of A is 10-100% of the total mass of the oxide activator.

The invention provides a low-temperature co-fired ceramic material emitting white light and a preparation method thereof. The ceramic material comprises the following components in percentage by mol: 10 to 20 percent of CaO, 20 to 30 percent of B2O3, 50 to 60 percent of SiO2, and 1 to 9 percent of optical activating agent ions. The invention also relates to the preparation method of the material, namely, a sol-gel method for preparing the low-temperature co-fired ceramic material emitting white light. The invention has the advantages that: 1, the preparation process is simple and advanced, the sintering temperature is low by adopting the Sol-gel method and is between 800 DEG C and 900 DEG C, the sintering shrink rate at the temperature is controllable between 13 percent and 17 percent, and a glass ceramic material has a flat and smooth surface, as well as higher strength; 2, the dielectric constant is adjustable between 4(1MHz) and 6 (1MHz), and the coefficient of dielectric loss is lower than 0.002; 3, the light emission intensity is high, the material can emit yellow and blue light under activation of ultraviolet light with the wavelength of between 320nm and 410nm, the white light obtained by mixing the blue light and the yellow light can be used for illuminating and displaying; and 4, based on the advantages, the low-temperature co-fired ceramic material can be applied to the fields of white light LED (Light Emitting Diode) lamps, integrated ceramic substrates and other electronic devices and semiconductors, as well as microelectronic packaging materials.

The invention provides a microwave dielectric ceramic material with an adjustable dielectric constant and a near-zero frequency temperature coefficient and a preparation method thereof. The microwave dielectric ceramic material includes a main crystal phase and a modification additive, and the structural formula of the main crystal phase is xAl ₂ o ₃ -yMg ₂ TiO ₄ ‑zCaTiO ₃ , wherein: x+y+z=1.0, 0.2≤x≤0.6, 0.3≤y≤0.75, 0.05≤z≤0.10; the modified additive is MnCO ₃ , SnO ₂ , Ga ₂ o ₃ Any one or a mixture of two or more of them. The microwave dielectric ceramic material of the present invention has the following advantages: 1) The dielectric constant is adjustable in a wide range, and εr is adjustable from 12 to 17; 2) It has low loss: Q*f≥60000GHz; 3) Near zero frequency The temperature coefficient τf is 0±5ppm/℃; 4) The raw materials are cheap and easy to obtain, non-toxic and environmentally friendly; 5) The preparation process is simple, no special equipment and harsh process conditions are required, it is suitable for industrial production, and can be widely used in various fields of microwave communication.

The invention discloses microwave dielectric ceramics and a polytetrafluoroethylene-ceramic composite substrate, and preparation methods thereof, and belongs to the field of organic/inorganic composite materials. A microwave dielectric ceramic material is represented by the general formula: Na[0.5-x-y]Li[x]K[y]Sm[0.5-m-n]Nd[m]Bi[n]TiO[3], wherein 0.3<=x<=0.5, 0<=y<=0.05, 0.3<=m<=0.5, and 0<=n<=0.05. The microwave dielectric ceramics have the advantages of high dielectric constant, low dielectric loss, adjustable dielectric constant and temperature coefficient and the like.

The present invention discloses a low dielectric polyimide fiber and a preparation method thereof, and belongs to the field of functional organic fibers. The fiber is prepared as follows: a copolymer polyamide acid spinning solution is prepared by condensation polymerization of hexafluorodianhydride (6FDA) and other dianhydride diamine; wet or dry-wet spinning process is used for spinning, poly amidoacid as-spun fiber is obtained by solidification and water washing; and the low dielectric polyimide fiber is prepared by thermal imidization and drawing processing of the fiber by gradient temperature, the tensile strength is up to 2.46GPa, initial modulus reaches 82.5GPa, and dielectric constant is as low as 2.55. The present invention provides a preparation method of the low dielectric polyimide fiber, has the characteristics of simple preparation method, low equipment requirements, extensive sources of raw materials, and continuous spinning production, and is suitable for industrial promotion.

The invention relates to a microwave dielectric material and provides a preparation method for a high-dielectric high temperature-resistant microwave dielectric composite material, which belongs to the field of manufacturing technology for composite materials. The objective of the invention is to overcome the technical problem of low ceramic solid phase content in traditional preparation methods. The preparation method comprises the following steps: 1, surface modification of a ceramic filling material in virtue of a silane coupling agent; 2, mixing of ceramic powder with resin powder; and 3, compression molding. The composite material prepared in the invention has the characteristics of a high dielectric constant, low loss, high temperature resistance, high thermal conductivity, a small thermal expansion coefficient, simplicity and environmental protection. The preparation method provided by the invention is used for preparation of the high-dielectric high temperature-resistant microwave dielectric composite material.

The invention discloses a microwave medium ceramic material and a preparation method thereof, and belongs to the field of electronic ceramics and manufacturing of the electronic ceramics. The preparation method of the ceramic material provided by the invention comprises the following steps of performing ball milling mixing, granulation, shaping, rubber discharging and sintering on 96.4 to 97.6 mass percent of (CaLiSm)TiO3 system ceramics and 2.4 to 3.6 mass percent of doping agents to prepare the microwave medium ceramic material using CaTiO3 as a main crystal phase. A quality factor is not obviously reduced; meanwhile, regulating a frequency temperature coefficient to a value near zero is realized; a dielectric constant is adjustable; the lithium volatilization in the ceramic material is inhibited; the crystal particle abnormal increase phenomenon is relieved; the structure compactness of the ceramic material is improved. Meanwhile, the ceramic material provided by the invention has the advantages that the process is simple; the sintering temperature range is wide; good process adaptability is realized; the industrial production is easy; the requirements in microwave communication industry can be favorably met.

This invention relates to a method for preparing nanopowder-modified lead zirconate titanate piezoelectric ceramic. The method pre-sinters the raw materials without nanopowder, and then adds TiO2 and/or ZrO2 nanopowder as a substitute for micropowder into the pre-sintered raw materials, which can reduce pre-sintering temperature by 100-300 deg.C and final-sintering temperature by 50-100 deg.C, and can adjust the crystalline and properties of pre-sintered sample as well as the electrical properties of the sintered piezoelectric ceramic. Nanopowder-modified piezoelectric ceramic sintered at 1150 deg.C has a Curie point increased by 50-100 deg.C. Besides, the piezoelectric ceramic has excellent impact stability (TC = 350-400 deg.C; epsiv = 350-900; KP = 0.42-0.65), stable process and good repeatability. The piezoelectric ceramic can be used to produce ceramic frequency discriminator and ceramic filter.

The invention discloses a high-performance microwave dielectric ceramics and a preparation method thereof. The principal crystalline phase is (1-x)CaTiO3-x(LayNd(1-y))GaO3, CaCO3, TiO2, La2O3, Ga2O3 and Nd2O3 are taken as raw materials, and the modified doping agent comprises BaCO3 and SrCO3. The (1-x)CaTiO3-x(LayNd(1-y))GaO3 microwave dielectric ceramics is prepared according to the traditional solid-phase reaction method. The provided microwave dielectric ceramic material has excellent microwave dielectric performance, the relative dielectric constant epsilon r is adjustable between 40 and 45, Q*f is 40000-45000GHz, the resonant frequency temperature coefficient can be continuously adjusted, and the microwave dielectric ceramics can be widely applied to preparing dielectric resonators, filters, duplexers and other microwave devices in the modern communication base station.

The invention discloses a ceramic adapter plate structure, which comprises a ceramic substrate, a first surface insulating layer, a second surface insulating layer and a conductive through hole, wherein the first surface insulating layer is arranged at the first side of the ceramic substrate; the second surface insulating layer is arranged at the second side, opposite to the first side, of the ceramic substrate; and the conductive through hole is arranged in the ceramic substrate and penetrates through the ceramic substrate.

The invention relates to a low-temperature-sintered temperature-stable composite microwave dielectric ceramic and a preparation method thereof. The composite microwave dielectric ceramic comprises the following components: a low-temperature-sintered microwave dielectric ceramic material with a negative resonant frequency temperature coefficient and a low-temperature-sintered microwave dielectric ceramic material with a positive resonant frequency temperature coefficient. According to the invention, the low-temperature-sintered microwave dielectric ceramic material with a negative resonant frequency temperature coefficient or the low-temperature-sintered microwave dielectric ceramic material with the positive resonant frequency temperature coefficient is used as a main material, a low-temperature-sintered microwave dielectric ceramic material with the same structure and an opposite resonant frequency temperature coefficient is added as an adjusting material through a two-phase compounding method, and compounding is conducted to form a multiphase ceramic material or a solid solution so as to obtain a low-temperature-sintered microwave dielectric ceramic material having a nearly-zero resonance frequency temperature coefficient. The problems that existing microwave dielectric ceramic is high in sintering temperature, and the temperature coefficient of resonance frequency changes greatly along with temperature are solved. The microwave dielectric ceramic material has a wide application scope in the LTCC low-temperature-sintered microwave dielectric ceramic materials.

The invention provides microwave dielectric ceramics of a perovskite structure and a preparation method thereof. The chemical composition of the ceramics is (1-x)Ca1-z(Li0.5Sm0.5)zTiO3-xLa1-ySmyAlO3,wherein x is greater than or equal to 0.1 and less than or equal to 0.6, y is greater than or equal to 0 and less than or equal to 1, and z is greater than or equal to 0 and less than or equal to 0.4.The preparation method comprises the following steps that 1) a calcium source, a lithium source, a samarium source and a titanium source are mixed and are subjected to primary crushing, and roastingis carried out so as to obtain Ca1-z(Li0.5Sm0.5)zTiO3; and 2) the Ca1-z(Li0.5Sm0.5)zTiO3, an aluminum source and a rare-earth metal source are mixed and then are subjected to primary crushing, roasting is carried out, secondary crushing and pressing are carried out, and sintering is carried out to form the ceramics so as to obtain the ceramics. According to the ceramics, the relative dielectric constant is adjustable, the loss is low, and the temperature coefficient of resonant frequency is adjustable.

The present invention discloses a low-temperature sintering moderate permittivity Li-Nb-Ti-based microwave dielectric ceramic material and a preparation method thereof. The material is prepared from a lithium niobium titanium-based material and a glass burning reducing agent accounting for 0.5 to 6.0 wt% of a principal crystalline phase by solid-phase reaction, the lithium niobium titanium based material composition is LiaNbbTicO3, wherein a is greater than 1.2 and less than 1.4, b is greater than 0.3 and less than 0.4, and c is greater than0.5 and less than 0.7. The glass burning reducing agent is prepared from the raw materials comprising lithium carbonate (Li2CO3), zinc oxide (ZnO), aluminum oxide (Al2O3), silicon dioxide (SiO2), diboron trioxide (B2O3) and a trace additive component. The low-temperature sintering LTCC (low temperature co-fired ceramic) microwave dielectric ceramic prepared by the method is good in sintering at 850-900 DEG C, high in moderate dielectric constant (epsilon r of 45 to 50) and quality factor Q * f (greater than or equal to 8000GHz), can be used in manufacturing of low-temperature co-fired ceramic systems (LTCC), multilayer dielectric resonators, microwave antennas, filters and other microwave devices, and has a great use value in the industry.

The invention provides a dielectric material, a dielectric film, a flexible organic field effect transistor (OFET) prepared by the dielectric film, a preparation method of the flexible organic field effect transistor (OFET), and the application thereof in the field of electronic equipment. The dielectric material and the dielectric film contain polymethyl methacrylate and polyacrylic acid. The thickness of the dielectric film is 1-2 microns. According to the preparation method of the flexible OFET, the dielectric film is processed on a substrate covered with a grid electrode. After that, the spin-coated treatment of an organic semiconductor layer is conducted with a solution. Finally, a source electrode and a drain electrode are evaporated. The dielectric film disclosed by the invention issmall in electricity leakage, adjustable in dielectric constant, controllable in thickness, and high in strength/flexibility. The dielectric film and the flexible OFET are good in electrical performance, and excellent in application prospect in the aspect of low-energy-consumption flexible electronic equipment. The preparation method of the dielectric film and the flexible OFET is low in cost andsimple and convenient in process.

The invention belongs to field of electronic ceramic and manufacturing thereof and in particular relates to a compound microwave dielectric ceramic material and a preparation method thereof. A chemical formula of the material is Zn0.15+0.35xTi0.55-0.05xNb0.3+0.7xO2+2x (x is equal to 0.2 to 0.8mol); the material is prepared from raw materials including ZnO, TiO2 and Nb2O5 and is prepared through asolid-phase method; the material has a medium dielectric constant (40 to 84) and low loss (1.10*10<-4> to 3.02*10<-4>), and the frequency-temperature coefficient is nearly zero. The content of two phases is adjusted through adjusting an x numerical value, low sintering temperature is ensured and the effect of improving the microwave dielectric performance is realized. The compound microwave dielectric ceramic material is applicable to manufacturing of multilayered dielectric resonators, microwave antennas, microwave capacitors, filters and the like.

The invention discloses dielectric powder for a 5G filter and a preparation method of the dielectric powder. The chemical structural formula of the dielectric powder for the 5G filter is (1-z)A4M2O9-zBxDyTiO3, wherein the phase A is composed of two crystal phases of A4M2O9 and BxDyTiO3, z is the molar fraction of the BxDyTiO3 phase, A is one of Mg and Zn, M is one of Sb, Ta, Nb and V, z is largerthan 0.1 and smaller than 0.48, and x is larger than 0 and smaller than 0.48; B is one of Ca, Sr and Ba, D is at least one of Sr, Sm, La, Ce, Nd, Sn and Co, and the total valence algebraic sum of BxDyTiO3 is zero due to the valence combination of the x, y and B and D elements, wherein 0.5 < x < 0.9, y < 1. The invention discloses dielectric powder for a 5G filter and a preparation method of the dielectric powder, belongs to the technical field of preparation of dielectric ceramic raw materials, and proves that the dielectric ceramic powder has the characteristics of adjustable dielectric constant, high quality factor and near-zero temperature drift, and is stable in performance, wide in application prospect and relatively large in popularization potential when being applied to a 5G communication filter.