32 results about "Negative thermal expansion" patented technology

The application discloses a SiO2-coated negative thermal expansion film and application thereof, and belongs to the technical field of temperature measurement. 12 :Nd 3+ The precursor solution is calcined to obtain the negative thermal expansion film, and then SiO2 solution is added dropwise on the negative thermal expansion film to obtain the SiO2-coated Yb2W3O 12 :Nd 3+ The SiO2-coated negative thermal expansion film is loaded on the opal template. 12 :Nd 3+ As a matrix, the SiO2 coating does not affect the luminescence of the negative thermal expansion film, and makes the Yb2W3O 12 :Nd 3+ The luminescence of the film in the near infrared is significantly enhanced. In addition, compared with the negative thermal expansion material film without the SiO2 coating, the negative thermal expansion material film is more sensitive to temperature.

Embodiments of the present disclosure relates to a composite material, a working stamp, and a preparation method thereof. The composite material includes a polymer matrix, a plurality of SMA nanoparticles, and a plurality of NTE material nanoparticles. The SMA nanoparticles are dispersed in the polymer matrix. The NTE material nanoparticles are dispersed in the polymer matrix. At a first temperature, the composite material is in a cured state and a thermal expansion coefficient of the composite material is zero (0) or near zero. When the composite material is cooled from the first temperature to a second temperature, the composite material spontaneously contracts caused by phase transformation of the SMA nanoparticles.

The application provides a PrMnO3-based negative thermal expansion material and a preparation method, and belongs to the technical field of negative thermal expansion materials. The negative thermal expansion material is of an orthogonal phase Pnma structure and a 3D cross Mn-O bond network. The negative thermal expansion temperature range of the negative thermal expansion material can be adjusted by adjusting the amount of Bi ions replacing Pr ions. The addition amount of the Bi ions satisfies that the ratio of the molar amount of the Bi ions to the molar amount of A-site ions is less than 50%. The application introduces Bi 3+ for the first time in the A-site of pure PrMnO3 3+ , and directionally introduces a "Bi 2 6s 2 lone pair electron functional site" in the crystal lattice. The PrMnO3-based negative thermal expansion material stably maintains the orthogonal phase Pnma structure and the 3D cross Mn-O bond network, and achieves the purpose of mildly and accurately controlling the negative thermal expansion temperature range.

The object of the present invention is to provide a negative thermal expansion material that consistently exhibits excellent negative thermal expansion characteristics over a wide temperature range of -30 to 150°C, and shows a more gradual volume decrease with increasing temperature compared to Zn2P2O7 between 100 and 150°C. The negative thermal expansion material of the present invention is characterized by containing 5 to 90 parts by mass of zinc pyrophosphate per 100 parts by mass of copper pyrophosphate, wherein the BET specific surface area of ​​the copper pyrophosphate is 0.2 to 8.0 m². 2 The BET specific surface area of ​​the zinc pyrophosphate is 0.2 to 8.0 m² / g. 2 It is preferable that it be / g.

This invention relates to the field of fiber optic sensing technology, specifically to a method for fabricating a low-temperature temperature-sensitive fiber grating based on a negative thermal expansion material coating, and the low-temperature temperature-sensitive fiber grating structure thereof. The method includes the following steps: preparing and pre-treating an optical fiber core layer; coating the outer periphery of the optical fiber core layer with nano-sized zirconium hafnium to obtain a stress transfer layer; preparing a low-temperature negative thermal expansion coefficient sensitizing material powder and coating it on the outer periphery of the optical fiber stress transfer layer to obtain a negative thermal expansion material sensitizing coating layer; constructing a porous structure on the surface of the obtained negative thermal expansion material sensitizing coating layer to form a porous layer on the surface of the negative thermal expansion material; and encapsulating a composite shell structure on the outside of the porous layer on the surface of the negative thermal expansion material to obtain a metal sheath layer. The fiber grating structure provided by this invention, for adapting to the production of temperature sensors, can simultaneously solve the failure problems of traditional sensors in the 4K ultra-low temperature region, the interference problems of electrical sensors in strong electromagnetic field environments, and the sealing failure problems caused by material brittleness in cryogenic environments.

The application discloses a mineral casting and a preparation method and application thereof, and belongs to the technical field of mineral casting. The mineral casting provided by the application is embedded with isotropic negative thermal expansion material. By embedding the isotropic negative thermal expansion material in the mineral casting, the thermal expansion coefficient of the mineral casting is reduced, the manufacturing precision is improved, and the isotropy of the obtained mineral casting is good, the deformation amount in each direction is uniform, and the mineral casting has wide application in machine tool manufacturing, building or transportation.

The application discloses a preparation method of a low-expansion high-toughness composite oxide solid electrolyte, which comprises the following steps: S1: compounding a solid electrolyte precursor, a grain boundary toughening agent and a stress buffer into a composite powder; S2: mixing the composite powder with a negative thermal expansion filler to prepare a plurality of mixed powders with a gradient change in the content of the negative thermal expansion filler; S3: preparing a green body from the plurality of mixed powders, and making the negative thermal expansion filler form a concentration gradient in the green body along the thickness direction; and S4: sintering the green body, making the grain boundary toughening agent form a toughening phase at the grain boundary in the sintering process, and finally obtaining the low-expansion high-toughness composite oxide solid electrolyte. The preparation method can make the oxide solid electrolyte have low thermal expansion, high fracture toughness, high density and self-healing characteristics, and can meet the strict requirements of long-term durability and reliability of electrolytes in a wide temperature range, long service life and high-power solid-state batteries.

An oil-filled pressure core includes: an oil-filled cavity, at least partially surrounded by a base and corrugated sheets; pressure-conducting oil filled in the oil-filled cavity; a pressure-sensitive element disposed in the oil-filled cavity for receiving the pressure of the pressure-conducting oil and converting the pressure into an electrical signal; and a filling block fixed in the oil-filled cavity, which has a negative coefficient of thermal expansion within a certain temperature range. This invention utilizes the characteristic of the filling block's volume contraction when the temperature rises to compensate for or counteract the volume expansion of the pressure-conducting oil caused by temperature increases, thereby effectively reducing the change in the volume of the pressure-conducting oil with temperature, reducing zero-point drift caused by the thermal expansion of the pressure-conducting oil, and improving the measurement accuracy and stability of the sensor.

To provide a negative thermal expansion material further improved in negative thermal expansion characteristics of a copper-vanadium composite oxide of Cu2 V2O7.SOLUTION: The negative thermal expansion material comprises a copper-vanadium composite oxide represented by general formula (1): CuxMgyVzOt (1) (where 1.70≤x≤2.15, 0<y≤0.25, 1.90≤z≤2.10, and 6.00≤t≤8.00, provided that 1.80≤x+y≤2.20).SELECTED DRAWING: None

In the field of lithium-ion batteries, the present invention specifically provides a positive electrode piece and a method for manufacturing the same. The lithium-ion battery comprising the positive electrode piece comprises a positive electrode active material layer, the positive electrode active material layer comprises a positive electrode material, a negative thermal expansion material, a conductive agent, and a binder, the characteristic value J of the positive electrode piece satisfies 0.001 ≤ J ≤ 0.005, and J = R(F) / ρ, where R(F) represents the peak intensity ratio of the main peak (F) of the negative thermal expansion material and the (003) characteristic peak of the positive electrode material in the XRD spectrum of the positive electrode piece, and ρ is the surface density (mg / cm³) of the positive electrode piece. 2 The provided positive electrode piece simultaneously possesses low volume expansion, high structural stability, and high temperature stability, and at the same time, the lithium-ion battery containing this positive electrode piece combines excellent capacity performance, multiplier performance, cycle performance, and energy density.

The application discloses a lithium ion battery and an electric device, and relates to the technical field of secondary batteries. The application creatively introduces a specific proportion of a negative thermal expansion material (such as ZrW2O8) into a positive active material layer, utilizes the volume shrinkage effect of the negative thermal expansion material when heated, effectively offsets the thermal expansion of a high-nickel positive electrode and the mechanical expansion internal stress of a silicon-carbon negative electrode, and reserves a safety buffer space for the battery cell from a macro-physical level. Meanwhile, in combination with a strictly defined positive / negative electrode capacity ratio (N / P), the risk of lithium precipitation and dendrite puncture under a large rate is further prevented, so that the lithium ion battery provided by the application can have high energy density, extreme safety and excellent fast charging and discharging performance.

This invention provides a wide-temperature-range multiphase low-expansion lightweight aluminum-based composite material and its preparation method, belonging to the technical field of ultra-low expansion alloy materials. The aluminum-based composite material is formed by mixing and sintering at least two phases of negative thermal expansion particles and aluminum matrix powder. The negative thermal expansion particles are La... 1‑z C z (Fe 1‑x‑y A x B y ) 13 The series comprises A, a transition metal, B, a metal or half-metal element in the p-block, and C, a lanthanide metal, with a concentration of 0 ≤ x < 0.2, 0.05 < y < 0.25, and 0 ≤ z < 1. The volume percentage of the aluminum matrix is ​​55%–75%. Aluminum is combined with metal-based negative thermal expansion particles. Since metal-based negative thermal expansion materials have higher thermal conductivity than ceramic-based materials, combining them with the aluminum matrix achieves high thermal conductivity. Furthermore, this invention employs at least two phases of negative thermal expansion particles, with the expansion ranges of the two negative thermal expansion particles overlapping to achieve a low expansion effect over a wide temperature range.

The present application belongs to the technical field of semiconductor devices, and relates to a near-field thermal radiation device with thermal rectification and thermal stability, which is arranged in a vacuum cavity shell and comprises a negative thermal expansion substrate, an emitter, a thermal expansion substrate and a receiver. The negative thermal expansion substrate is arranged on a top wall in the vacuum cavity shell, the emitter is arranged on a side of the negative thermal expansion substrate away from the top wall of the vacuum cavity shell, the thermal expansion substrate is arranged on a bottom wall in the vacuum cavity shell, and the receiver is arranged on a side of the thermal expansion substrate away from the bottom wall of the vacuum cavity shell. The emitter and the receiver are used for near-field radiation heat transfer. By adjusting the temperature of the emitter and the receiver, the negative thermal expansion substrate and the thermal expansion substrate are expanded or contracted, the vacuum gap between the emitter and the receiver is changed, the heat flux of the near-field thermal radiation device is changed, and the near-field thermal radiation device realizes the functions of a thermal diode with thermal rectification and a thermal stabilizer with thermal stability.

The application belongs to the technical field of metamaterials, and discloses a design method and product of a zero / negative thermal expansion coefficient metamaterial composed of a single solid material. The method comprises the following steps: dividing a design domain into a high-pressure gas region, a low-pressure gas region, and a solid region for isolating the high-pressure gas region and the low-pressure gas region; setting the thermal expansion coefficient and the elastic modulus of the solid region; adjusting the shape of the solid region and the gas pressure of the gas region so that the deformation of the solid region under the pressure difference between the high-pressure gas region and the low-pressure gas region at a changed temperature in the design domain is equal to the zero thermal or negative thermal expansion of the solid region under the temperature change, thereby obtaining the required shape of the solid region and the gas pressure. Through the application, the thermal expansion performance is accurately controlled, and the application is suitable for aerospace, precision instruments and other application scenarios with high requirements for size thermal stability.

This invention discloses a low-warpage solder resist ink material, its preparation method, and its application, belonging to the field of ink material preparation technology. It addresses the technical problem that the anti-shrinkage and anti-warpage properties of existing ink materials need further improvement. Specifically, it comprises the following components by weight: 30-50 parts alkali-soluble modified resin, 15-20 parts shrinkage-modified filler, 2-5 parts photoinitiator, 0.5-3 parts pigment, 1-3 parts leveling agent, and 15-25 parts solvent. This invention involves preparing negative thermal expansion nano-zirconium tungstate, coating it with polydopamine, grafting photosensitive double bonds to obtain an anti-shrinkage filler, esterifying o-cresylaldehyde epoxy resin with acrylate, and then modifying it with a dibasic anhydride to obtain an internally plasticized resin. Finally, the components are premixed under yellow light and water-cooled three-roll milling to obtain a low-warpage solder resist ink, which not only improves the anti-shrinkage and anti-warpage properties of the ink material but also enhances its mechanical properties.

The present application relates to the field of engineering applications, and particularly relates to a negative thermal expansion composite material and application thereof in solid oxide batteries. 3+ The preparation of the negative thermal expansion composite material comprises the following steps: (1A) reducing Ce(OH)2 nanoparticles in a cerium source precursor and depositing on the surface of a negative thermal expansion material to obtain a suspension; (2A) performing in-situ hydrothermal reaction on the suspension to remove a solvent to obtain an intermediate; and calcining the intermediate to obtain a negative thermal expansion composite material NTE@CeO2. The present application realizes thermal mismatch relaxation through interface structure and stress state regulation, avoids the problems of enhanced sintering sensitivity and performance fluctuation caused by electrode doping or phase ratio adjustment, is beneficial to improving the consistency of single cell performance and service life in the batch preparation process, does not depend on electrode chemical composition adjustment, has a wider process window, and has higher product consistency.

The application provides a double-material negative thermal expansion structure and a design method thereof based on a multi-island genetic optimization, which is applied to the field of passive compensation of thermal deformation of high-precision equipment in an extreme thermal environment, a double-material negative thermal expansion structure with a triangle and a trapezoid as basic geometric units is designed, and a multi-island genetic algorithm is introduced to globally optimize the structure parameters, and the core problem of deformation caused by thermal mismatch between parts is solved. The deformation in a certain direction under thermal load is significantly inhibited, thereby providing a passive, real-time and reliable solution for realizing long-term stability of equipment or structures in an extreme thermal environment.

The application discloses a CoZr3-based single-phase zero thermal expansion material in an ultra-wide temperature range, part of Co atoms in a CoZr3 material is replaced by Fe atoms, and the chemical formula of the zero thermal expansion material is Co 1‑x Fe x Zr3, x =0.28~0.32, and is prepared by an arc melting method. The application adjusts the thermal expansion performance of the CoZr3 alloy by changing the doping amount of Fe under the premise that the material has a single orthorhombic structure, weakens the negative thermal expansion behavior of the CoZr3 alloy due to phonons, and obtains the single-phase CoZr3-based material with ultra-wide temperature range zero thermal expansion, and the material perfectly compensates the negative thermal expansion behavior of the original alloy, and obtains the zero thermal expansion material in the ultra-wide temperature range.

The application relates to a preparation method of a directional layered structure negative thermal expansion reinforcing body and a wide-temperature-range near-zero expansion layered structure metal matrix composite material, and relates to a negative thermal expansion reinforcing body and a metal matrix composite material. In order to solve the problems of high density, poor toughness and interface reaction caused by the high volume fraction of the negative thermal expansion phase of the zero expansion metal matrix composite material, the application takes spatial configuration design as the core design and pressure infiltration as the key technology, the internal stress distribution of the composite material is effectively controlled through spatial configuration design, the residual stress caused by the mismatch of the thermal expansion coefficients or the preparation process is significantly controlled, the material is endowed with better mechanical bearing capacity, the excessive deformation of the metal matrix can be inhibited through the geometric constraint effect, the zero expansion temperature interval of the sample is effectively widened through the structure design, and the near-zero expansion metal matrix composite material with high comprehensive performance is obtained.

This invention provides a filler for low dielectric loss resin compositions, a low dielectric loss resin composition, a molded body for high-frequency equipment, and high-frequency equipment. The filler is an inorganic filler with excellent low dielectric properties and a negative coefficient of thermal expansion, which can be applied to electronic components such as circuit boards, information communication equipment, etc. This invention is a filler for low dielectric loss resin compositions, characterized in that it includes a first inorganic filler with a negative coefficient of thermal expansion, wherein the dielectric loss tangent of the first inorganic filler is below 0.002 at a frequency above 1 GHz and a temperature of 25°C.

The application belongs to the technical field of coating and discloses a kind of corrosion and wear resistant composite coating and preparation method, comprising: obtaining titanium alloy powder and negative thermal expansion material powder as raw material powder;After ball milling treatment to raw material powder, drying is carried out, to obtain dry mixed powder;The dry mixed powder is mixed with organic binder solution and stirred to obtain paste-like mixture;The paste-like mixture is coated on the surface of pretreated substrate multiple times, dried and laser cladded to form a multilayer composite coating on the surface of the substrate, which overlaps each other;The multilayer composite coating overlapping each other is laser remelted to obtain a corrosion and wear resistant composite coating, thereby obtaining a composite coating with high hardness, high bonding strength and excellent corrosion and wear resistance.

The present application relates to a kind of ABS lead-acid battery tank cover heat sealing process, comprising the following process steps: step one, preparation is prepared from ABS material and shell cover;Shell is provided with battery tank, and first groove is provided on the tank wall of battery tank;Cover surface is outwardly convex and forms connecting rib, and second groove is provided on connecting rib;Step two, connecting rib is heat melted and handled, comprising the following substeps: a, the outer surface of connecting rib is heat melted and forms first molten layer;B, preheat negative thermal expansion material to same temperature with connecting rib heat melting in step a, when the outer surface of connecting rib heat melting is completed, the negative thermal expansion material is filled into second groove;Step three, the connecting rib of cover is aligned with the first groove of tank wall and is pressed and docked, with the negative thermal expansion material in second groove gradually cooling, so that connecting rib expands and first molten layer is pressed in the inner wall of first groove, so that the connection of cover and battery tank is firm.

This invention discloses a method for preparing a lead-free material with a low coefficient of thermal expansion for flexible electronics, belonging to the field of polymer composite materials technology. The material prepared by this method comprises, along its thickness, layers A, B, and C. Layers A and C use aromatic polyimide as a matrix, with surface-modified hafnium tungstate phosphate nanoparticles dispersed thereon. Layer B uses poly(p-phenylene-2,6-benzobisoxazole) nanofibers as a continuous phase framework, loaded with hexagonal boron nitride nanosheets and Ti3C2T… x MXene nanosheets were obtained by hot pressing three layers together under an argon atmosphere. The resulting material exhibits a coefficient of thermal expansion reduced to 1.2–2.9 ppm / K and an in-plane thermal conductivity of 18.7–25.1 W / (m·K), combining excellent flexibility and mechanical properties. It is suitable for flexible copper-clad laminates, chip packaging, and integrated heat dissipation and shielding substrates for high-power electronic devices.

The present application provides a post-spinel oxide and a preparation method thereof. Specifically, the present application provides a post-spinel oxide having the following chemical formula: CaMFe2O5; wherein M is Cu, Co, Zn or Ni. The present application also provides a preparation method of the post-spinel oxide of the present application. The post-spinel oxide of the present application has new properties due to its unique structure, such as abnormal lattice distortion, low-dimensional magnetism, large coercive field and / or negative thermal expansion, etc. The present application provides a new way and new idea for the exploration and discovery of post-spinel oxide.

The application discloses a functional current collector with improved thermal stability, a preparation method thereof, a pole piece and a battery. The structural composition of the functional current collector comprises a polymer base layer, wherein the polymer base layer contains a negative thermal expansion material; an aluminum oxide primer layer is arranged on both sides of the polymer base layer; and an aluminum metal plating layer is arranged on both sides of the aluminum oxide primer layer. The negative thermal expansion material is an X-MOF / rGO composite material, wherein X is selected from any one of Cu, Fe, Ni and Co; and the ligand of the MOF is aspartic acid. The X-MOF / rGO introduced in the polymer base layer realizes the synergistic improvement of the thermal stability, interface durability and conductivity.

The application discloses a multi-phase stress self-adapting composite sealing paste, a preparation method thereof and a semiconductor packaging structure. The paste comprises 60-75% low-melting-point lead-free glass powder, 8-15% nano metal alloy particles, 3-7% negative thermal expansion compensation phase, 10-15% organic carrier and 0.5-2% modified additive according to mass percentage. The softening point Ts of the nano metal alloy particles is lower than the glass transition temperature Tg of the glass powder, the nano particles are uniformly distributed on the surface of the glass powder and form a micro anchoring structure. In the sealing cooling stage, the Ts-Tg temperature difference gradient is utilized to promote the plastic rheology of the nano particles, and the negative thermal expansion compensation phase is utilized to neutralize the interface residual thermal stress. The preparation method comprises surface modification, vacuum stirring, three-roll grinding and conductivity monitoring. The packaging structure comprises a substrate, a cover plate and a paste sintering sealing layer. The application improves the air tightness and reliability of the semiconductor packaging and is suitable for MEMS sensors and high-power modules.

This invention belongs to the field of rolling bearing technology and relates to a rolling bearing cage based on a tensile negative thermal expansion structure, including a cage body, a negative thermal expansion drive structure, and a traction structure. This invention enables the negative thermal expansion drive structure, with its large coefficient of thermal expansion, to expand significantly when the temperature rises. The traction structure transforms this expansion deformation into a radially inward stretching effect on the inner and outer rings of the cage. This causes the inner diameter guide surface of the inner ring and the outer diameter guide surface of the outer ring to exhibit radial contraction with increasing temperature, resulting in a negative thermal expansion characteristic. This automatically increases the guide clearance under high-temperature conditions, effectively maintaining a reasonable fit clearance between the cage and the rolling elements and raceway flanges, suppressing excessive contact and friction between components, reducing vibration and noise during bearing operation, improving the bearing's operational stability in high-temperature environments, and extending the bearing's service life.