12results about How to "Improve intrinsic coercive force" patented technology

The invention discloses a cerium-rich R-T-B series sintered magnet and a preparation method thereof.The preparation method comprises the following steps that S1, mixed powder is prepared, the mixed powder is obtained by evenly mixing first R-T-B series alloy powder rich in cerium and poor in rare earth and second R-T-B series alloy powder poor in cerium and rich in rare earth, the sphericity degree of the first R-T-B series alloy powder is not lower than 0.75; and S2, preparing the mixed powder into the R-T-B series sintered magnet. According to the preparation method, a low-Ce-content grain shell layer is constructed in the cerium-rich R-T-B series sintered magnet, so that the intrinsic coercive force of the cerium-rich R-T-B series sintered magnet is improved. By means of the preparation method, the high-performance R-T-B series sintered magnet rich in the Ce element can be prepared, and application of Ce resources in the R-T-B series sintered magnet is promoted.

The permanent magnet comprises, by mass, REaNbFe100-a-b-c-dCocBd, RE is a combination of two or more of rare earth elements including lanthanum, cerium, praseodymium and neodymium and must contain the cerium element, the mass percentage of the cerium element is not lower than 6%, N is one or more of aluminum, copper, gallium and zirconium, the sum of the mass percentage of the elements is not lower than 6%, the sum of the mass percentage of the elements is not lower than 6%, the sum of the mass percentage of the elements is not lower than 6%, and the sum of the mass percentage of the elements is not lower than 6%. The permanent magnet is prepared from two raw materials including a main phase alloy and an auxiliary phase alloy through double-alloy formation, the main phase alloy comprises a cerium element, and the auxiliary phase alloy comprises a cobalt element; through the addition of the cobalt element, the precipitation of the CeFe2 phase can be reduced, a new main phase is formed, the main phase volume ratio of the permanent magnet is increased, the problem of magnetic performance deterioration caused by the addition of the cerium element is avoided, and the prepared cerium-containing rare earth permanent magnet has high coercive force.

The present invention belongs to the technical field of permanent magnetic materials, and relates to a heavy rare earth-free high-performance lanthanum-cerium rare earth permanent magnet and a manufacturing method thereof. The chemical composition of the lanthanum-cerium rare earth permanent magnet is expressed as: [(R1) 1‑x (R2) x ] a M1 b M2 c M3 d B e Fe 1‑a‑b‑c‑d‑e , wherein: 10%≤x≤25%, 29.5%≤a≤32.5%, 1%≤b≤2%, 0.5%≤c≤1%, 0%<d<2.5%, 0.85%≤e≤0.95%, wherein R1 is one or both of Pr and Nd, R2 is one or both of La and Ce, M1 is Cu and Ga, M2 is Nb and Zr, and M3 is one or more of Al, Co, and Mn. The present invention reasonably controls the composition of the permanent magnet to obtain a high-performance lanthanum-cerium magnet without adding heavy rare earth elements, effectively reduces the production cost of the magnet, and broadens the application of the lanthanum-cerium magnet in the market.

The invention relates to a SmFeN magnet and a preparation method and application thereof.The preparation method comprises the following steps that after SmFeN powder, a first binder and a second binder are mixed, granulation, injection molding, first binder removal and curing are conducted in sequence, the SmFeN magnet is obtained, and the first binder is different from the second binder. The use amount of the binders is increased by adopting the first binder and the second binder, smooth proceeding of the injection molding process is guaranteed, then the first binder is removed, the skeleton binder is reserved, the content of the binders remaining in the SmFeN magnet is reduced, molecules of the second binder are migrated through curing, and therefore the SmFeN magnet is formed. And air holes generated by removing the first binder are filled, so that the density of the magnet is improved. The SmFeN magnet prepared by the method is high in magnet density and high in strength; the intrinsic coercive force is high, and the thermal stability is high; the residual magnetism and the maximum magnetic energy product are large, and the magnetic performance is excellent.

The invention relates to the technical field of rare earth magnetic materials, in particular to a novel cerium-iron-boron rare earth magnet and a three-stage aging coercive force improving process. The magnet comprises the following components in percentage by weight: 16 to 24 percent of Pr-Nd, 6 to 12 percent of Ce, 0 to 0.5 percent of Zr, 0 to 1 percent of Al, 0 to 0.5 percent of Cu, 0.9 to 1.1 percent of B, 0 to 1.2 percent of Co, 0 to 0.3 percent of Ti, 0 to 3 percent of Gd, and the balance of Fe, wherein the Pr-Nd accounts for 16 to 24 percent, the Ce accounts for 6 to 12 percent, the Zr accounts for 0 to 0.5 percent, the Al accounts for 0 to 1 percent, the Cu accounts for 0 to 0.5 percent, the B accounts for 0.9 to 1.1 percent, the Co accounts for 0 to 1.2 percent, the Ti accounts for 0 to 0.3 percent, the gadolinium accounts for 0 to 3 percent, and the balance is Fe. The method comprises the steps of raw material weighing, smelting and sheet casting, hydrogen decrepitation grinding, magnetic powder forming and sintering forming. The technical problem that in the prior art, due to the fact that the cerium content of a cerium-iron-boron magnet is low, the applicable temperature range of the cerium-iron-boron magnet is limited is effectively solved.

The invention discloses a vacuum sintering furnace which comprises a vacuum furnace shell, a heating chamber, a material box uncovering device, a vacuum system and an inflation system. The heating chamber is arranged in the vacuum furnace shell and comprises a heat preservation screen, a heater, an uncovering assembly and a furnace hearth assembly from outside to inside. A sintering material box is placed on the furnace hearth assembly; the uncovering assemblies are located on the inner side of the heater and distributed on the two sides of the sintering material box. The material box uncovering device is located on the upper portion of the vacuum furnace shell, and a guide shaft penetrates through the vacuum furnace shell and the heat preservation screen of the heating chamber to be connected with the uncovering assembly. The material box uncovering device can drive the guide shaft to drive the uncovering assembly to move up and down. More than three layers of sintering material boxes are arranged in the vertical direction, each layer of sintering material box is provided with more than one sintering material box cover, and the cover opening assembly can drive the multiple sintering material box covers to ascend or descend at the same time, so that the sintering material box covers of the multiple layers of sintering material boxes are opened or closed at the same time in the vacuum sintering process.

The present invention discloses a microstructure control method for sintered NdFeB quick-setting slabs, wherein the pouring environment is improved by a tundish, and nano-metal powder is blown into the liquid as a nucleation modifier when the liquid reaches the copper roller, and the nano-metal powder arrives on the copper roller pre-treated with concave surfaces together with the iron-neodymium-boron steel liquid, and the nucleation and columnar crystal growth process are controlled by the high-speed operation of the copper roller; at the same time, a strip crushing device with a trumpet-shaped opening is provided and air-cooled, and finally a quick-setting slab with an ideal microstructure with good columnar crystal growth, no amorphous and microcrystals, and no agglomeration of neodymium-rich phases is obtained. Compared with the alloy addition method and the grain boundary diffusion heavy rare earth method, the grain refinement technology of the present invention neither consumes too much rare earth resources nor limits the size of the magnet; the prepared sintered magnet has fine grains and is evenly distributed, which is conducive to liquid phase sintering, and can achieve an increase of 3 to 5 KOe in the intrinsic coercivity of the sintered magnet.

The application discloses a modified slow-release rare earth alloy, a sintered neodymium-iron-boron magnet and a preparation method thereof. 1‑m X m , m is an atomic percentage content, 35at%<=m<=76at%; wherein, RE is a rare earth element, composed of light rare earth elements and heavy rare earth elements; X is selected from at least one of Ga, In, Si, Ge, Sn, Sb, Bi, S, Se and Te. The modified slow-release rare earth alloy can improve the magnetic performance and high-temperature stability of the sintered neodymium-iron-boron magnet.

The present invention belongs to the field of magnetic materials, and in particular to a sintering preparation method for improving the intrinsic coercivity of NdFeB magnets. The method comprises: orienting and molding the magnet into powder, then encapsulating it with metal foil and performing vacuum shaping, and then performing protective heat treatment to obtain a low-oxygen content magnet. The present invention uses metal foil to encapsulate and isostatically compact the metal foil so that the metal foil and the NdFeB green body are closely attached. The metal foil participates in the sintering heat treatment process of the NdFeB magnet, optimizes the grain boundary of the magnet through component diffusion, plays the role of repairing the grain boundary, improving the crystal structure, and improving the intrinsic coercivity of the magnet; and protects the NdFeB green body from oxidation and avoids the increase of oxygen content, while eliminating the process of removing the packaging paper, thereby improving production efficiency.

The present application relates to sintered Nd-Fe-B rare earth permanent magnet material technical field, specifically to a kind of preparation process of gallium cobalt double-element regulated inorganic fluoride grain boundary diffusion neodymium-iron-boron magnet.The process will be pretreated sintered Nd-Fe-B magnet as matrix, inorganic fluoride powder and gallium source are first ball milled in anhydrous system, form Ga-F interface fixed intermediate slurry;Then add cobalt source and cooperate into film agent, dispersing agent to obtain sequential fixed type composite diffusion source slurry, after coating on the surface of magnet, by low-temperature oxygen-free pre-conversion, grain boundary main diffusion and segmented tempering to obtain modified magnet.The present application is conducive to control the contact sequence and migration state of gallium and cobalt in diffusion source particles, so that neodymium-iron-boron rare earth permanent magnet material can improve intrinsic coercivity while maintaining good remanence, demagnetization curve squareness and high temperature stability.

The invention belongs to the technical field of high-performance sintered neodymium-iron-boron magnets, and particularly discloses a preparation method of a neodymium-iron-boron diffusion magnet. According to the preparation method, through the design of a layered structure, composite diffusion sources with different components are placed on the two faces of the magnet, then thermal diffusion treatment is conducted, and the grain boundary diffusion magnet is obtained after annealing. The high-performance magnet is prepared through dry or wet diffusion, the intrinsic coercive force of the magnet can be remarkably improved, and heavy rare earth resources are saved. According to the method, in the preparation process of the grain boundary diffusion magnet, the layered structure design is matched with the grain boundary diffusion technology, the grain boundary phase composition of the magnet can be well enriched, the utilization rate of heavy rare earth resources is remarkably increased, and the diffusion magnet product prepared through the method is good in performance consistency and high in yield. The method can be applied to working conditions with high requirements for magnetic performance, and is suitable for industrialization.

The invention discloses a high-strength magnetic shoe and a production process thereof, and belongs to the technical field of magnetic shoe production, and the magnetic shoe comprises the following raw materials: 80-90 parts of ferric oxide, 12-15 parts of strontium carbonate, 0.4-0.6 part of calcium carbonate, 0.1-0.2 part of zirconium oxide, 0.5-0.7 part of boric acid, 0.5-0.7 part of cobalt oxide, 2-6 parts of yttrium oxide, 0.3-0.5 part of silicon dioxide and 0.2-0.4 part of bismuth trioxide. And the high-strength magnetic shoe is prepared through secondary sintering and wet pressing molding processes. By utilizing the synergistic effect of zirconium oxide and yttrium oxide, while the magnetic performance of the magnetic shoe is improved, the phase change toughening effect of zirconium oxide is maximized, and the mechanical strength of the magnetic shoe is enhanced. The raw material ratio is adjusted, the preparation method is simple, and the high-strength magnetic shoe can be prepared.