35results about How to "High curie temperature" patented technology

The invention provides a manganese zinc ferrite material as well as a preparation method and application thereof. The manganese zinc ferrite material is prepared from main components and auxiliary components, the main component is prepared from the following components in molar ratio: 51.5 to 53.0 mol percent of ferric oxide, 17.0 to 18.5 mol percent of zinc oxide and 29.0 to 30.0 mol percent of manganese oxide; the auxiliary components comprise the following components according to the total weight of the main components: 200 to 2000 ppm of nano-scale bismuth oxide, 200 to 2000 ppm of nano-scale calcium carbonate, 200 to 2000 ppm of nano-scale molybdenum oxide, and 0 to 4000 ppm of nano-scale cobalt oxide. By optimizing the components and the proportion of the ferrite material, improving the preparation process and organically combining the formula and the process, the ferrite material with high magnetic conductivity, high Curie temperature, wide frequency and wide temperature is finally prepared, and large-scale popularization and application are facilitated.

The invention relates to a manganese zinc ferrite material and a preparation method thereof, the manganese zinc ferrite material comprises main components and auxiliary components, the main components comprise Fe2O3, ZnO and MnO, and the auxiliary components comprise CoO, CaO, Bi2O3 and MoO; and in the main components, the content of Fe2O3 is 52.0 to 53.0 mol percent, the content of ZnO is 18.0 to 19.0 mol percent, and the content of MnO is 28.0 to 30.5 mol percent in terms of mole percent. According to the manganese-zinc ferrite material, the initial permeability mu i is greater than or equal to 12000 in a wide temperature range of 0-145 DEG C, and the manganese-zinc ferrite material has a relatively low temperature coefficient in the temperature range; the magnetic conductivity does not drop under the high frequency of 300kHz, and mu i is greater than or equal to 9000; the Curie temperature Tc is greater than 145 DEG C, so that the stability of the manganese-zinc ferrite material applied to the field of automotive electronics or a conventional anti-EMI common-mode filter is greatly improved.

The invention discloses a dielectric and magnetic loss coupling type multi-frequency high-absorption composite wave-absorbing material. The chemical formula of the composite wave-absorbing material is (FeCoNiCraMn) x. (BaTiO3) y, the invention also discloses a preparation method of the composite wave-absorbing material, which comprises the following steps: step 1, mixing iron, cobalt, nickel, chromium and manganese, and carrying out suspension smelting, vacuum gas atomization and sieving to obtain high-entropy alloy spherical powder; secondly, the flaky high-entropy alloy is obtained after ball milling; thirdly, the flaky high-entropy alloy is naturally cooled and then dried; and fourthly, the dried flaky high-entropy alloy is mixed with barium titanate powder, and ball milling is carried out. According to the composite wave-absorbing material, the FeCoNiCrMn series high-entropy alloy provides magnetic loss capacity, barium titanate provides dielectric loss capacity, the synergistic effect of multiple loss mechanisms is achieved, and the composite wave-absorbing material is suitable for the technical field of wave-absorbing materials.

The invention belongs to the field of magnetic materials, particularly relates to a high-power garnet ferrite and a preparation method thereof, and provides a high-power garnet ferrite and a preparation method thereof aiming at the defects that high residual magnetism ratio, low resonance line width, high spin wave line width and high Curie temperature of the garnet ferrite in the prior art are difficult to consider at the same time, and the high-power garnet ferrite is obtained through Co < 2 + >-Ge < 4 + > or Co < 2 + >-Si < 4 + > ion combined substitution. The garnet ferrite with high remanence ratio, low resonance line width, high spin wave line width and high Curie temperature can be obtained by reasonably designing the doping amount of Co < 2 + > ions and Mn < 3 + > ions and matching with proper Dy < 3 + > doping. Aiming at the defect that low resonance line width, high spin wave line width and high Curie temperature of garnet ferrite are difficult to consider at the same time, the invention provides a Co < 2 + > ion and Dy < 3 + > ion combined substitution method, so that the garnet ferrite can have low resonance line width, high spin wave line width and high Curie temperature at the same time.

The invention relates to the technical field of soft magnetic ferrite materials, in particular to a nickel-zinc ferrite material as well as a preparation method and application thereof. The invention provides a nickel-zinc ferrite material. The nickel-zinc ferrite material comprises the following raw materials: main components and auxiliary components, wherein the main components comprise Fe2O3, NiO, ZnO and CuO; the mass percentage of Fe2O3 in the main component is 64.05 to 68.72 wt%, the mass percentage of NiO in the main component is 14.12 to 17.36 wt%, the mass percentage of ZnO in the main component is 11.61 to 15.02 wt%, and the mass percentage of CuO in the main component is 3.82 to 4.45 wt%; based on the total weight of the main components, the auxiliary components comprise 0.2 wt%-0.6 wt% of Al2O3, 0.05 wt%-0.25 wt% of SiO2 and 0.1 wt%-0.35 wt% of MnO2. According to the nickel-zinc ferrite material, specific main components and auxiliary components are selected, and the contents of the main components and the auxiliary components are limited, so that all the components generate a synergistic effect, and finally the nickel-zinc ferrite material with excellent comprehensive performance is obtained.

The present invention relates to the field of piezoelectric ceramic materials, in particular to a piezoelectric ceramic material with high Curie temperature and high piezoelectric coefficient and a preparation method thereof, wherein the structural formula is as follows: (1‑x‑y)(Bi2O2) 2+ (A m‑1 B m O 3m+1 ) 2‑ ‑xLiTaO3‑yLaAlO3, where A is Na + , K + , Ca 2+ , Sr 2+ , Ba 2+ , Pb 2+ 、Bi 3+ ,La 3+ Any one or more of the following; B is Fe 3+ 、Ti 4+ , Nb 5+ , W 6+ Any one or more of the composites; m is an integer between 1‑4; 0<x≤0.2; 0<y≤0.2. The piezoelectric ceramic material prepared by the present invention has a high Curie temperature and excellent electrochemical properties. The maximum piezoelectric constant can reach 35pC / N, which is significantly improved compared with the currently reported bismuth layered structure piezoelectric ceramics.

The invention relates to the field of piezoelectric ceramic materials, in particular to a piezoelectric ceramic material with high Curie temperature and high piezoelectric coefficient and a preparation method thereof, the structural formula of the piezoelectric ceramic material is as follows: (1-x-y) (Bi2O2) < 2 + > (Am-1BmO3m + 1) < 2-x > LiTaO3-yLaAlO3, A is any one or more of Na < + >, K < + >, Ca < 2 + >, Sr < 2 + >, Ba < 2 + >, Pb < 2 + >, Bi < 3 + > and La < 3 + >; b is any one or more of Fe < 3 + >, Ti < 4 + >, Nb < 5 + > and W < 6 + >; m is an integer between 1 and 4; 0 < x < = 0.2; 0 < y < = 0.2, the piezoelectric ceramic material prepared by the method has high Curie temperature and excellent electrochemical performance, the maximum piezoelectric constant can reach 35pC / N, and compared with the currently reported bismuth layered structure piezoelectric ceramic, the piezoelectric ceramic material has the advantage that the piezoelectric constant is greatly improved.

The application relates to a nickel-zinc-copper ferrite and a preparation method and application thereof, the nickel-zinc-copper ferrite comprising main components and auxiliary components; the main components comprise Fe2O3 64-66.7 mol%, NiO 9-12 mol%, ZnO 13.5-19 mol% and CuO 3-9.5 mol% with the total mole percentage being 100 mol%; the auxiliary components comprise Bi2O3 0.3-1.5 wt%, Co2O3 0.1-0.6 wt%, CaCO3 0.03-0.08 wt% and ZrO2 less than or equal to 0.1 wt% with the total mass percentage of the main components being taken as a standard. The content of Fe2O3, ZnO, NiO and CuO is controlled, the content of the auxiliary components is matched and adjusted, the prepared nickel-zinc-copper ferrite has high saturation magnetic induction intensity, high magnetic permeability, high Curie temperature, low residual magnetic induction intensity and low specific temperature coefficient, and can be better applied to power inductance or common-mode inductance.

The invention relates to the technical field of ferrite preparation, and particularly provides an iron-poor manganese-zinc ferrite material and a preparation method thereof.The iron-poor manganese-zinc ferrite material comprises main components and auxiliary components, and the main components comprise 65-67 wt% of Fe2O3, 10-12 wt% of ZnO and the balance Mn3O4 by taking the total weight of the main components as 100 wt%; the main components comprise Fe2O3, ZnO, Mn3O4, CaCO3 and Co2O3, the auxiliary components comprise, by weight, 100-2000 ppm of CaCO3 and 1000-10000 ppm of Co2O3, and by controlling the content of Fe2O3, ZnO, Mn3O4, CaCO3 and Co2O3 in the formula, the iron-poor manganese zinc ferrite material has the advantages of being low in temperature, high in magnetic conductivity, high in Curie temperature, high in frequency and high in impedance.

The invention relates to the technical field of piezoelectric ceramic materials, in particular to potassium-sodium niobate-based lead-free ceramic suitable for high-power devices and a preparation method, the chemical general formula of the potassium-sodium niobate-based lead-free ceramic is 0.96 (K < 0.45 > Na < 0.55 >) NbO < 3-0.04 > Bi < 0.5 + x > Na < 0.5 > ZrO < 3-0.005 > CuO, and x is one of 0, 0.03, 0.05, 0.08 and 0.10. According to the potassium-sodium niobate-based lead-free ceramic suitable for the high-power device and the preparation method, the potassium-sodium niobate-based lead-free ceramic has excellent comprehensive electrical properties including high piezoelectric constant, high quality factor, high Curie temperature and low dielectric loss, and is suitable for being applied to high-power electronic equipment.

The invention relates to the field of piezoelectric ceramic materials, in particular to high-temperature piezoelectric ceramic and a preparation method thereof, the structural formula of the high-temperature piezoelectric ceramic is as follows: (1-x-y) (Bi < 1-p > Lnp) FeO < 3-x > Ba (Ti < 1-q > Alq) O < 3-y > BiYbO < 3-z > wt% GeO < 2 >, 0.1 < = x < = 0.5, 0.01 < = y < = 0.05; 0.1 < = z < = 1; 0.1 < = p < = 0.5, 0.01 < = q < = 0.05, no lead element is contained, and no harm is caused to human health and living environment in the manufacturing, using and waste treatment processes.

The invention belongs to the technical field of stealth materials, and particularly discloses a radar wave-absorbing repair coating capable of being rapidly cured at low temperature as well as a preparation method and application of the radar wave-absorbing repair coating. Comprising the following raw materials: 18%-22% of organic silicon resin, 3%-7% of epoxy modified organic silicon resin, 4%-8% of a diluent, 56%-64% of an absorbent, 2.5%-3.5% of a curing agent, 1.5%-2.5% of an accelerant, 1.5%-2.5% of a thermal initiator and 1%-3% of an auxiliary agent. Wherein the curing agent is formed by compounding a reaction type curing agent and a catalytic type curing agent, and the mass percent of the reaction type curing agent to the catalytic type curing agent is (2-3): (1-1.5). The radar wave-absorbing repair coating provided by the invention can realize low-temperature rapid curing, has good tensile bonding strength, impact resistance and long-term test temperature resistance, is mature and controllable in process, and completely meets the application of external field rapid repair of radar wave-absorbing coatings of various equipment.

The invention discloses a room-temperature ferroelectric material with an extremely low coercive field, a large spontaneous polarization value and a high Curie temperature and a preparation method and application thereof, the room-temperature ferroelectric material is a zero-dimensional organic-inorganic hybrid perovskite crystal material, has the following chemical formula (C2H8N) 4PbBr6, has the spontaneous polarization value of 2.3 [mu] C / cm < 2 > and the coercive field of 0.11 kV / cm, and has the Curie temperature of greater than 400 K, and the room-temperature ferroelectric material is a ferroelectric material with an extremely low coercive field, a large spontaneous polarization value and a high Curie temperature. Wide application prospects are realized in low-loss nonvolatile memories, sensors, capacitors, optical modulators, electromagnetic nondestructive testing and battery technologies.

The present application discloses a piezoelectric ceramic material and a preparation method thereof and a piezoelectric device. The piezoelectric ceramic material has the chemical formula: 0.03Bi(Zn 1 / 2 Ti 1 / 2 )O3‑0.07Pb(Mn 1 / 3 Nb 2 / 3 )O3‑0.9Pb(Zr 0.46 Ti 0.54 The piezoelectric ceramic material provided in the present application can ensure that the sintered product has good piezoelectric properties, a high Curie temperature and low loss at a relatively low sintering temperature.

The present invention relates to the field of piezoelectric ceramic materials, in particular to a high-temperature piezoelectric ceramic and a preparation method thereof, the structural formula of which is as follows: (1-x-y)(Bi 1‑p Ln p )FeO3‑xBa(Ti 1‑q Al q )O3‑yBiYbO3‑zwt%GeO2 wherein Ln is a lanthanide element; 0.1≤x≤0.5, 0.01≤y≤0.05; 0.1≤z≤1; 0.1≤p≤0.5, 0.01≤q≤0.05, and does not contain lead, and will not cause harm to human health and living environment during the manufacturing, use and waste disposal processes.

A low coercivity YIG substrate material for LTCC circulator and a preparation method thereof, belonging to the technical field of electronic ceramics. The present invention adopts Bi-Li-P combined substitution and introduces Bi 3+ , Li + , P 5+ Ion substitution of Y at 24c in YIG 3+ ions, Fe at positions 16a and 24d 3+ ions, resulting in significant lattice distortion, which greatly reduces the sintering temperature of the material, reducing the solid phase reaction broadening component in the ferromagnetic resonance line width of the sample. + , P 5+ The amount of ion substitution controls the ferrite grain growth and pore exclusion during the sintering process, so that the material obtains multiple dense microstructures; on the one hand, it is beneficial to increase the bulk density of the material and reduce the porosity, while obtaining a high saturation magnetization intensity and reducing the pore width in the ferromagnetic resonance line width; on the other hand, the increase in the average grain size of the material is beneficial to reducing the coercive force of the material.

The invention discloses a nickel-copper-zinc ferrite material and a preparation method thereof. The nickel-copper-zinc ferrite material comprises a main material and a toughening additive, wherein in terms of the total molar weight of the main materials being 100%, the main materials comprise 34%-48% of Fe2O3, 10%-12% of NiO, 5%-6% of CuO and the balance ZnO; the toughening additive is at least one of 300 to 1500 ppm of V2O5, 300 to 1000 ppm of MoO3 and 300 to 1000 ppm of Nb2O5 based on the total weight of the main materials being 100%. The preparation method comprises the following steps: (1) weighing the raw materials; (2) mixing the main materials, adding water, sanding, adding a polyvinyl alcohol solution, and carrying out spray granulation; (3) presintering and cooling; (4) adding a toughening additive, and sanding; and (5) adding a polyvinyl alcohol solution, and carrying out spray granulation, pressing and sintering to obtain the product. The nickel-copper-zinc ferrite material disclosed by the invention has the advantages of high magnetic conductivity, high resistivity, high toughness and the like, and is suitable for being applied to a common-mode inductor of a network transformer.

This invention relates to the field of piezoelectric ceramics technology, and in particular to a composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic and its preparation method. The general formula for high-temperature piezoelectric ceramics is: Ca 1‑x (LiCe) x / 2 Bi 3.75 Nd 0.25 Ti 3.935 Sc 0.065 O 15 , where x is a complex high-valence ion (LiCe). 4+ Twice the molar amount, x = 0.02, 0.05, 0.08, 0.10. This invention employs the above-mentioned composite ion-modified bismuth layered bismuth titanate calcium-based high-temperature piezoelectric ceramic and its preparation method to meet the application requirements in high-temperature environments while ensuring the material's environmental friendliness.

This invention discloses a cobalt-based Hassler alloy material, its preparation method, and its application. The preparation method includes the following steps: (1) Weighing cobalt powder, iron powder, and germanium powder in a molar ratio of 2:(1~1.75):(0.25~1), mixing them, placing them in a tungsten carbide grinding jar, adding anhydrous ethanol, adding grinding balls, and ball milling; (2) Drying and sieving the ball-milled powder, taking the sieved magnetic alloy powder, sealing it in a vacuum quartz tube, heat-treating it using a muffle furnace, and cooling it to room temperature with the furnace to obtain a cobalt-iron-germanium Hassler alloy. This invention uses a ball milling method, which can effectively change the surface morphology of the alloy powder, making it form a flake powder with a larger specific surface area, thereby improving the electromagnetic absorption performance of the magnetic alloy; by selecting and changing the proportion of the Hassler alloy components, the saturation magnetization of the magnetic alloy can be effectively increased, its Curie temperature can be increased, and the electromagnetic wave absorption performance of the magnetic alloy at high temperatures can be improved.

The invention provides a lead-free thermal sensitive ceramic with high Curie temperature and low resistance and a preparation method thereof, and belongs to the technical field of electronic ceramic elements. The chemical formula of the main component of the thermal sensitive ceramic material is (Ba1-x-yLax( Bi0. 5Na0. 5) y) (Ti < 0.9999 > Mn < 0.0004 >) O3, wherein x is more than or equal to 0.001 and less than or equal to 0.004, and y is more than or equal to 0.001 and less than or equal to 0.0075. The preparation method comprises the following steps: mixing (Bi0. 5Na0. 5) TiO3 powder synthesized by a two-stage heating hydrothermal method and (Ba1-xLax) TiO3 powder synthesized by a solid-phase reaction method with a Mn (NO3) 2 aqueous solution and a sintering aid AST powder, and then granulating, forming, dumping and sintering. The barium titanate-based thermal sensitive ceramic prepared by the method disclosed by the invention has extremely low room temperature resistivity and relatively high Curie temperature.

The invention relates to the technical field of piezoelectric ceramic materials, and particularly discloses a composite high-temperature piezoelectric ceramic material and a preparation method thereof, the chemical general formula of the composite high-temperature piezoelectric ceramic material is Bi < 0.5-x > [Mn < 0.25 > Sn < 0.5 > Pr < 0.25 >] < x > Na < 0.5 > TiO < 3 + a >% WO < 3 + b >% ZnSO4, the components and proportion of the base material are adjusted and optimized, meanwhile, WO3 and ZnSO4 with specific content are adopted as additives, the piezoelectric activity and thermal stability of the piezoelectric ceramic can be improved, functional filler is added in the preparation process, sintering efficiency is improved, the ceramic material forms a more compact crystal structure, and the piezoelectric ceramic has a good application prospect. The strength and the toughness of the ceramic material are enhanced. The composite high-temperature piezoelectric ceramic material has high Curie temperature and high piezoelectric activity, and the application range of the piezoelectric ceramic material can be effectively widened.

The application discloses a doped modified lead metaniobate-based high-temperature piezoelectric ceramic and a preparation method thereof. The doped modified lead metaniobate-based high-temperature piezoelectric ceramic has a general formula of PbNb2O6+x mol% Nb2O5+y wt% Sc2O3+z wt% SrCO3+delta mol% Ta2O5; wherein x=0-8, y=0-0.8, z=0-1, and delta=0-12. The application solves the problems of sintering difficulty, low density and low piezoelectric coefficient of pure PbNb2O6 by adding excess Nb2O5; on the basis, Sc 3+ , Sr 2+ , and Ta 5+ ions are doped in sequence, so that the piezoelectric performance of the PbNb2O6-based piezoelectric ceramic is continuously improved while the high Curie temperature is ensured.

The invention discloses a magnetic control mechanism magnetic shell material and a preparation method thereof, and belongs to the technical field of power distribution equipment, and the magnetic control mechanism magnetic shell material comprises the following chemical component element proportions (%): 0.5-0.55% of C; 6.0 to 8.0% of chromium (Cr); 0.20 to 0.25% of nickel (Ni); 0.60 to 0.80% of Si (silicon); less than or equal to 0.035 of phosphorus P; mn: less than or equal to 0.1; and the balance of Fe. The preparation method comprises the following steps: weighing raw materials and preparing; mixing the raw materials, and forging a blank to obtain a steel ingot; machining the steel ingot, and machining the steel ingot into the shape required by the magnetic shell according to the design size, so as to obtain a preliminarily formed magnetic shell; and performing heat treatment on the preliminarily formed magnetic shell to obtain the magnetic shell of the magnetic control mechanism. According to the magnetic shell, the saturation flux density, the residual magnetism and the alloy coercive force of a machine body are improved, the strength, the hardness and the corrosion resistance are improved, the magnetic shell material is a low-alloy carbon steel system, the alloy cost is low, and the magnetic shell can be widely popularized in the technical field of power distribution switch equipment.

The invention discloses edge nitrogen vacancy carbon nitride with room-temperature ferromagnetism and a preparation method and application thereof. The edge nitrogen vacancy carbon nitride is an amorphous nanosheet and is of a graphite-like structure with an edge nitrogen vacancy. The thickness of the edge nitrogen vacancy carbon nitride nanosheet is 3-8 nm, and the length or width of the edge nitrogen vacancy carbon nitride nanosheet is 1-15 microns; the method comprises the following steps: calcining urea, grinding and annealing in an argon environment, cleaning and drying to obtain orange-red edge nitrogen vacancy carbon nitride; the preparation method disclosed by the invention has the characteristics of simple process, high efficiency and easiness in repetition, and the prepared edge nitrogen vacancy carbon nitride has the characteristics of high purity, high Curie temperature and room-temperature ferromagnetism, and can be applied to the fields of spinning electronic devices, topological quantum devices, magnetic storage and the like.

The potassium sodium niobate-based piezoelectric ceramic provided in this application introduces a specific proportion of Fe 3+ , making Fe 3+ The potassium sodium niobate-based piezoelectric ceramics formed with defective dipoles in combination with oxygen vacancies can have a higher Curie temperature and good temperature stability; at the same time, the piezoelectric ceramics of the present application have a larger piezoelectric coupling constant kp and mechanical quality factor Q m , and it can be used as a sintering aid to reduce the temperature of ordinary sintering and improve the density of ceramics; the potassium sodium niobate-based piezoelectric ceramics of the present application can be prepared through industrial raw materials and are easy to achieve large-scale production.

This utility model discloses a detachable multifunctional physiotherapy device, comprising: a shell, a scraping component, an oil-absorbing component, a moxibustion component, a heating component, a fan component, and a power module; wherein, the shell is T-shaped and divided into a front cover and a rear cover; the scraping component has several evaporation holes at its head end and is connected to the front cover; the front end of the oil-absorbing component is connected to the rear end of the scraping component; the rear end of the moxibustion component is connected to the front end of the scraping component; the heating component is disposed inside the shell; the fan component is disposed inside the rear cover; a shaving cover is disposed between the heating component and the fan component; and the power module is disposed inside the shell. This utility model, through its T-shaped shell design, effectively solves the problem of inconvenience in back physiotherapy, improving the comfort and effectiveness of the therapy; the detachable connection of each component makes the replacement of parts such as the fat-absorbing cotton and moxa sticks easy and convenient, reducing equipment maintenance costs; it greatly facilitates equipment cleaning and extends the service life of the equipment.

The invention relates to the technical field of NdFeB magnets, and discloses a preparation method of the NdFeB magnet. By introducing elements such as Y and Ni, the collocation of magnet elements is optimized, the Curie temperature and coercive force of the NdFeB magnet are significantly improved, the temperature coefficient is reduced, and the disadvantage of poor heat resistance of the NdFeB magnet is improved; a rapid quenching thin strip, hydrogen explosion powder making and calendering forming process are adopted to refine the main phase grains, realize mechanical orientation, and enable the magnet to have higher magnetic properties; the surface of the NdFeB magnetic powder is modified by KH550, and chemical adsorption with the magnetic powder in the form of Si-O-covalent bonds is formed after dehydration and condensation, which is beneficial to improving the adhesion between the magnetic powder and the resin; a polyurethane elastomer binder containing a naphthyl group and a triazine group of a heat-resistant group can form a very stable system with the modified NdFeB magnet, so that the magnet has excellent dimensional stability under a high temperature environment.

The invention discloses a piezoelectric ceramic material, a preparation method thereof and a piezoelectric device, and belongs to the technical field of inorganic non-metallic materials, the chemical composition of the piezoelectric ceramic material is (1-a-b) Pb (Zr < 0.5 > Ti < 0.5 >) O < 3-b > Pb (Zn < 1 / 3 > Nb < 2 / 3 >) O < 3-a > Pb (Ni < 1 / 3 > Nb < 2 / 3 >) O < 3 + x wt% M + y wt% ZnO, wherein a is more than or equal to 0.04 and less than or equal to 0.08; 0.08 < = b < = 0.12; m is a sintering aid, x represents the mass percent of the sintering aid M in the mass of the ceramic matrix, and x is greater than or equal to 0 and less than or equal to 1; y represents the mass percent of ZnO in the mass of the ceramic matrix, and y is more than or equal to 0 and less than or equal to 1. According to the invention, the technical effects of high piezoelectric property, low sintering temperature and high Curie temperature are realized.

The invention discloses doped and modified lead metaniobate-based high-temperature piezoelectric ceramic and a preparation method thereof. The invention relates to doped and modified lead metaniobate-based high-temperature piezoelectric ceramic. The general formula of the piezoelectric ceramic is PbNb2O6 + x mol% Nb2O5 + y wt% Sc2O3 + z wt% SrCO3 + delta mol% Ta2O5, in the formula, x is equal to 0-8, y is equal to 0-0.8, z is equal to 0-1, and delta is equal to 0-12. The problems that pure PbNb2O6 is difficult to sinter, low in density, low in piezoelectric coefficient and the like are solved by adding excessive Nb2O5; on the basis, Sc < 3 + >, Sr < 2 + > and Ta < 5 + > ions are doped in sequence, so that the piezoelectric property of the PbNb2O6-based piezoelectric ceramic is continuously improved while the high Curie temperature is ensured.

The invention discloses a doping preparation method of a high-temperature stable rare earth magnet assembly, and relates to a magnetic material and a preparation technology thereof. Heavy rare earth elements such as terbium and dysprosium are compositely doped into a neodymium iron boron matrix, and technological parameters such as ball milling, compression molding, sintering and magnetic field oriented annealing are optimized, so that the coercive force and magnetic energy product stability of the magnet under a high-temperature working condition are remarkably improved. The method gives consideration to magnetic performance and cost control, is suitable for high-temperature application scenes such as a welding tool magnetic attraction device, effectively solves the problem that the magnetic performance attenuation of a conventional NdFeB magnet at high temperature is fast, improves the high-temperature reliability of the magnet, and prolongs the service life of the magnet.