81results about How to "Low room temperature resistivity" patented technology

The invention belongs to the field of polymer matrix composite manufacturing, and particularly relates to a preparation method of a carbon nanotube-graphene oxide mixed reinforced composite material. Graphene oxide and carbon naotubes are assembled into a nano-carbon mixed structure reinforcement with the high self-supporting property, and after resin matrix infiltration and polymerization, the carbon nanotube-graphene oxide mixed reinforced composite material is obtained; the porous carbon nanotube-graphene oxide reinforcement with the low density and the high specific surface area is prepared by taking 2-ethyl-4-methylimidazole as a bridge between the nanotubes and graphene oxide, and the reinforcement retains the respective characteristics of graphene oxide and the carbon nanotubes and is composited with multiple resin matrixes by serving as three-dimensional macroscopic continuous reinforcement with the high electricity conductivity and thermal conductivity, and then the multifunctional low-cost carbon nanotube-graphene oxide mixed reinforced composite material is prepared.

The invention relates to a conductive composite material and a PTC (Positive Temperature Coefficient) thermal sensitive element prepared from the same. The conductive composite material comprises the following components in parts by volume: 15-75 percent of crystalline polymer substrate and 25-85 percent of conductive filler with the particle size between 0.1 mum and 10 mum, wherein the conductive filler is dispersed in the crystalline polymer; and a coupling agent is titanic acid ester which accounts for 0.05-5 percent by volume of the conductive filler. The structural formula of the conductive composite material is (R1O)m-Ti-(OX-R2-Y)n, wherein radical R1 is alkyl, radical X is phosphoric acid easer base, radical R2 is alkyl, radical Y is acyloxy, m is more than or equal to 1 and less than or equal to 4, n is more than or equal to 1 and less than or equal to 3, and m and n are integers. The PTC thermal sensitive element prepared from the conductive composite material is formed by fixedly clamping a conductive composite material layer between two metal foils. The invention has the advantages that: the conductive material has high electric conductivity; and the PTC element prepared from the conductive composite material has very low room temperature resistivity, high PTC intensity and resistance reproducibility.

The invention discloses an NTC heat sensitive conducting ceramic material and a method for preparing the same. The method for preparing the NTC heat sensitive conducting ceramic material comprises the following steps: using BaCO3, SrCO3, SnO2 and Fe2O3 as main raw materials, mixing and ball-milling the raw materials, and drying the mixture to obtain a Ba1-ySryFexSn1-xO3 blank which is not doped, or doped singly, or doped compositely for a secondary ball milling; and adopting an ordinary ceramic preparation process. The B value of the NTC heat sensitive conducting ceramic prepared in the invention can reach 5,100K, and the resistivity at room temperature can be reduced to 2,800 omega.m. The NTC heat sensitive conducting ceramic material has simple preparation process and low cost, and the obtained products can be applied to the aspects of temperature measurement, temperature control, automatic gain adjustment, temperature compensation and the like.

The invention discloses a high-performance lead-free negative temperature coefficient temperature-sensitive thick film and a preparation method thereof. Major composite components are combined in two combination modes. In an inorganic phase I combination mode, (1-t)Ba1-yMyFe1-xSnxO3+tBaCo<II>zCo<III>2zBi1-3zO3, wherein t is more than or equal to 0.4 and less than or equal to 0.95 and is a molar ratio; and in an inorganic phase II combination mode, (1-m-1)Ba1-yMyFe1-xSnxO3+mBaCo<II>zCo<III>2zBi1-3zO3+1/2Ag2O, wherein m is more than or equal to 0.3 and less than or equal to 0.65; l is more than or equal to 0.05 and less than or equal to 0.3; m and l are molar ratios; and the composite components are uniformly mixed with an organic carrier in the mass ratio of 75:25 so as to form thick film resistance paste. The preparation method comprises the following steps of: printing the paste on a substrate by a screen printing process; flattening, baking, pre-sintering and repeatedly printing so as to obtain a thick film biscuit with a required thickness; and sintering the biscuit at the temperature of between 750 and 850 DEG C and preserving heat for 40 to 80 minutes so as to obtain the lead-free negative temperature coefficient temperature-sensitive thick film. The thick film has a simple preparation process and a low film forming temperature, the film thickness is between 10 and 100 mu m, the temperature sensitive constant value is between 2,500 and 5,500 K, the room temperature resistivity is between 150 ohm.cm and 10 M ohm.cm and the aging resistant time is over 800 hours.

The invention provides a positive plate and a lithium ion battery containing the positive plate. The safety of the battery cell is improved by controlling the seepage thresholds of the safety coatingcoating the surface of the positive current collector and the positive active material layer, and meanwhile, relatively high energy density and excellent electrical properties are ensured. Particularly, the seepage threshold value of the positive active material layer is small, and the addition amount of the conductive agent is small, so that a good electron path can be ensured, and the energy density of the positive plate can be increased.

The invention relates to a doped BKT-BT series lead-free positive temperature coefficient resistance ceramic material and a prepration method thereof, the general formula of the composition of the material is (Bi0.5K0.5)*1(Ba1-*1-*2)AX2)Ti1-yMyO3+Zmol%D, wherein, x1 is more than 0 and not more than 0.7, x2 is more than 0 and not more than 0.6%, y is more than 0 and less than 0.2%, Z is not less than 0 and less than 1, A is one or more of Ce, Y, La and Bi, M is one or more of Nb, Sb, Ta and Mo, and D is one or more of MnO2, TiO2, SiO2 and B2O3. For a series of the lead-free ceramic materials, TC, alpha, betaRT and resistance sudden jump Rmax/Rmin are respectively changed between 140 and 250 DEG C, between 10 and 45%/DEG C, between 20 and 60 omega.Cm and between 10<2> and 10<5> along with the change of x1, x2, y and Z.

The invention discloses a PTC (positive temperature coefficient) ceramic sintering method. The method comprises the steps that a PTC ceramic biscuit is put into a crucible, and subjected to quick temperature rise-heat preservation, quick cooling-heat preservation, and further quick temperature rise to slightly high temperature-heat preservation; after the three-step sintering technology, a sintering block body is compacted quickly, and then subjected to furnace cooling; and the density of ceramic reaches the theoretical density. The sintering block body experiences higher sintering temperature, and then is subjected to the heat preservation at a lower temperature by changing the ceramic sintering technology; quick moving of a crystal boundary is inhibited; the sintering block body with fine and uniform crystal grains can be obtained, and further treated at the slightly high temperature; the sintering time can be shortened greatly; and the ceramic which is compact in structure and uniform in grain size, and has lower room temperature resistivity and a higher PTC effect is obtained finally. The characteristics are beneficial for meeting various functional requirements, such as high sensitivity, high reliability, imoact resistance and high safety, of a PTC ceramic sensor.

The invention discloses a preparation method of a stannic oxide ceramic electrode, belonging to the field of a ceramic technology. The method comprises the steps of: by taking nano antimony-doped stannic oxide powder and CuO powder as sintering aids, blending SnO2 powder with the sintering aids; then, adding a dispersing agent and a bonding agent into the mixture obtained from the former step; and carrying out wet grinding, drying, crushing granulation and isostatic compaction and then firing to prepare the stannic oxide ceramic electrode, wherein the mass percent of the SnO2 powder is 83-91% of the ingredients, the mass percent of the nano antimony-doped stannic oxide powder in the sintering aids is 9-17% of the ingredients, and the mass percent of the CuO powder is 0-0.6% of the ingredients. The preparation method is simple in technology and high in product pass rate, and the obtained stannic oxide ceramic electrode is high in density and low in resistivity at the room temperature and the high temperature.

A process for preparing the electrically conductive titanate powder by gas-phase RE diffusion method includes such steps as thermally dissolving RE oxide in concentrated nitric acid, cooling using amide reagent to regulate its concentration to obtain RE contained panetrant, preheating carburizing furnace, dropping amide reagent into it, quickly loading titanate powder in the furnace dripping said penetrant in the furnace, and diffusing at 860-950deg.C for 3-6 hr.

The invention discloses a high-Curie-temperature lead-free barium-titanate-base PTCR (positive temperature coefficient of resistance) ceramic material which is composed of BaTiO3, BaBiO3, (Bi0.5Na0.5)TiO3, MnO2 and Si3N4. The chemical formula of the material is (1-x-y)BaTiO[3-x]BaBiO[3-y](Bi0.5Na0.5)TiO3, wherein x=0.001-0.003, and y=0-0.01. 0.00034-0.00038mol of MnO2 and 0.008-0.012mol of Si3N4 are added to prepare every 1mol of (1-x-y)BaTiO[3-x]BaBiO[3-y](Bi0.5Na0.5)TiO3. The preparation method comprises the following steps: weighing and mixing the raw materials according to the mole formula, adding water, carrying out ball milling on the mixture, drying, keeping the temperature, drying, granulating, pelleting, and sintering to obtain the PTCR thermistor. The doping of the proper amount of BaBiO3 can lower the room temperature resistivity of the BaTiO3 system, and can enhance the Curie temperature of the system. The BT-BaBiO3-BNT system can be adopted to obtain the high-Curie-temperature lead-free PTCR material with low room temperature resistivity.

The invention provides a preparation method of a conductive composite material and belongs to the field of material preparation. The preparation method is characterized by comprising the following steps: soaking graphene micro-flakes and an ultrahigh-molecular weight polyethylene powder in ethanol and performing ultrasonic dispersion by use of an ultrasonic cell smasher to form a uniformly distributed suspension; performing suction filtration and vacuum drying to remove the ethanol solvent, so that the graphene micro-flakes are evenly attached on the surface of the ultrahigh-molecular weight polyethylene particles; finally, performing compression molding on the obtained material, and then cooling to a room temperature under a constant pressure, thereby obtaining a raw material. The preparation process is improved, so that a more complete and stable effective conductive network structure can be formed inside the conductive composite material, and therefore, the percolation threshold of the material is greatly reduced, and the material has the maximum peak resistivity and relatively low room temperature resistivity. The preparation method of the conductive composite material is simple to operate, simple and convenient in process, and suitable for popularization and utilization in the related fields.

The invention discloses a graphite / phenol resin / (Ba-[1-x-y], Sr-[x], Pb-[y]TiO3 based PTC thermo-sensitive resistor and its making process, wherein its raw material and ingredients are (percentage by weight), Ba[1-x-y], Sr-[x], Pb[y]TiO3 based ceramic powder 62-78%, where x=0.005-0.35, y=0.002-0.56, graphite 14-28%, 5% phenolic resins containing PVA curing agent 8-18.6%. The invention also discloses the process for preparing the thermo-sensitive resistor.

The invention relates to a polyvinyl PTC thermo-sensitive conductive composite material, which comprises a base material and an additive, wherein the base material comprises 10-25% of LDPE, 20-40% of TiB2, 0-8% of CB and the balance of HDPE, and the additive comprises 0.1-0.3% of antioxidant1010, 1-3% of stearic acid, 1-2% vinyl trimethoxysilane, 3-5% of Sb2O3 and 8-12% of decabromodiphenyl ethane; and the adding amount of the additive is measured by the mass of organic matter components in the base material. The material has room temperature resistivity of 23.5omega . cm, long-term current capacity flow of greater than 100A and PTC intensity of 7.8, and resistance keeps stable after 100 thermal cycles.

The invention discloses a composite material for a thermistor and a preparing method thereof. The composite material is prepared from, by weight, 80-90 parts of high-density polyethylene, 25-35 parts of ethylene-vinyl acetate copolymer, 10-20 parts of polytetrafluoroethylene, 5-15 parts of polyvinylpyrrolidone, 25-35 parts of conductive filler, 6-8 parts of coupling agent, 3-5 parts of crosslinking agent, 1-3 parts of antioxidant and 2-4 parts of lubricant. The conductive filler is a mixture of titanium diboride and carbon fiber by the weight ratio of (6-10):1; the coupling agent is isobutyl triethoxy silane; the crosslinking agent is trimethylolpropane triacrylate. A positive-temperature-coefficient thermistor made of the composite material for the thermistor is low in room temperature electrical resistivity and high in PTC strength, after circulation for 100 times, the change rate of room temperature electrical resistivity and PTC strength is small, and the composite material has low room temperature, high PTC electrical resistivity and stability.

The invention discloses a polyethylene/titanium diboride PTC (Positive Temperature Coefficient) composite material and a preparation method thereof. The polyethylene/titanium diboride PTC composite material is prepared from the raw materials consisting of main materials and processing auxiliary agents, wherein the main materials comprise the following components in percentage by mass: 10-25 percent of low density polyethylene, 40.1-50 percent of TiB2, 0-6 percent of CB and the balance of high density polyethylene; and the processing auxiliary materials comprise antioxidant 1010, stearic acid, a coupling agent of vinyl trimethoxy silane, antimony trioxide and a fire retardant of decabromodiphenylethane. The polyethylene/titanium diboride PTC composite material has low room temperature resistivity, high voltage resistance, heavy current resistance, long-term flow stability performance, high PTC strength and high PTC stability.

The invention discloses a cellular heating ceramic containing rare earth oxide and a preparation method of the cellular heating ceramic. The cellular heating ceramic is prepared by mixing hybrid ceramic powder with 0.02 to 0.1 percent of Y2O3 according to the molar percentage ratio; and the hybrid ceramic powder comprises according to the molar percentage ratio: 96 percent MgAl2O4, 1 to 3 percent of SiO2 and 3 to 1 percent of TiO2 according to the molar percentage ratio. Through the adding of the rare earth oxide Y2O3 in the hybrid ceramic powder, the room temperature resistance rate of the cellular heating ceramic can be reduced effectively, and the density and the hardness of the cellular heating ceramic are improved; according to the molar percentage ratio, when the 0.06 percent of Y2O3 is added in the hybrid ceramic powder, the density and the hardness of the cellular heating ceramic are maximal, and are respectively 93.01% and 349.5HV; and meanwhile, the room temperature resistance rate of the cellular heating ceramic reaches the minimum 5.5*101 omega.m.

The invention provides a material with positive temperature coefficients, which is a product obtained by mixing a mixture containing conductive particles and polymers, wherein the conductive particlesare metal conductive particles with partially oxidized surfaces, and the oxygen content in the conductive particles is between 0.001 and 0.05 percent by weight. According to the material with positive temperature coefficients, the conductive particles are the metal conductive particles with partially oxidized surfaces so that the compatibility between the conductive particles and the polymers andthe dispersity of the conductive particles in the polymers can be improved; moreover, the material with positive temperature coefficients has high PTC intensity reaching as high as 10.4, and can still maintain low room-temperature resistivity at the same time.

The invention belongs to the field of a high-molecular material, and more specifically relates to a PTC thermistor base material and a preparation method thereof. The PTC thermistor base material comprises the following raw materials in parts by weight: 60-70 parts of HDPE, 15-20 parts of PET, 3-5 parts of EEA, 25-30 parts of silver-plated copper powder, 4-8 parts of carbon fiber, 0.8-1 part of graphene, 5-6 parts of palygorskite powder, 3-5 parts of basalt fiber, 3-4 parts of wollastonite, 2-3 parts of mica powder, 2-3 parts of dicumyl peroxide, 5-8 parts of a nano filling material, 3-5 parts of a coupling agent, 2-3 parts of an anti-oxidant, and 2-4 parts of an organosilicon fire retardant. The preparation method comprises the steps of weighing, premixing and mixing. The PCT thermistor has low room-temperature resistivity, high heat resistance, high stability and high intensity, and excellent comprehensive property.