55results about How to "Increase the maximum energy product" patented technology

The invention discloses a method for preparing sintered NdFeB with low dysprosium (Dy) content and high performance; the method comprises the following steps of: sputtering and plating the Dy element on the surface of jet mill powder by using the powder plate technology based on magnetron sputtering on the basis of preparing NdFeB powder, and then sufficiently dispersing the Dy element to micron-sized NdFeB crystal particles by dispersing the Dy element at high temperature in the sintering and tempering process, thereby achieving the effect of improving magnetic performance of the sintered NdFeB. Compared with the introduction of the Dy element in the proportioning process of the prior art, the method disclosed by the invention has the advantages: the low dysprosium content and high performance is limited in the nano-size by adopting the physical gas-phase deposition, the consumption quantity of the Dy element during the production process is controlled effectively and the preparationof sintered NdFeB with low dysprosium content and high performance is realized. Compared with the sintered NdFeB of the same components prepared by the traditional casting and powder metallurgy process, both the intrinsic coercivity and the maximum magnetic energy product of the sintered NdFeB rare-earth permanent magnetic material obtained according to the invention are improved obviously; compared with the sintered NdFeB with the same performance prepared by the traditional casting and powder metallurgy process, the dosage of the dysprosium element is reduced remarkably. The method can be widely applicable to producing and manufacturing sintered NdFeB with high performance.

The invention discloses a high-coercivity and high-stability neodymium iron boron magnet and a preparation method based on crystal boundary reconstruction. The preparation method comprises the steps of separating design and preparation of main alloy and crystal boundary phase alloy powder, nano-modification of crystal boundary phase, powder mixing, magnetic field profiling, isostatic pressing, sintering and thermal treatment. According to the high-coercivity and high-stability neodymium iron boron magnet and the preparation method is based on crystal boundary reconstruction and combines with a rich heavy rear earth novel crystal boundary phase and nano-modification technology, namely the rich heavy rare earth novel crystal boundary phase is redesigned and synthesized, in the process of magnetic sintering and tempering, magnetic hardening is achieved through spread of the heavy rare earth element to the boundary layers of the principle phase crystal grain, and thus a high-coercivity magnetic is prepared under the condition that no or less heavy rear earth is added in the principle phase. Meanwhile the distribution of the crystal boundary and the form of the crystal grain boundary are optimized through a nano-modification method, a pinning domain wall restrains counter magnetic field nucleation and crystal grain growth, and thus high coercivity and high stability of the neodymium iron boron is achieved. The high-coercivity and high-stability neodymium iron boron magnet and preparation method based on crystal boundary reconstruction is simple in process, low in cost and suitable for large-scale volume production.

The invention discloses a high-speed press forming method for an anisotropic binder-free neodymium iron boron magnet. The method comprises the following steps and the following process conditions of: (1) lubricating a mold wall; (2) filling magnetic powder in a mold cavity, then placing the mold cavity into a pulsed magnetic field with magnetic field intensity of 1.0 to 1.5 T and frequency of 0.02 to 0.1 Hz to perform orientation, and applying a pressure of 20 to 30 MPa to prepress at the same time; and (3) heating the mold to 130 to 150 DEG C and then performing press forming at the high speed of 10 to 17 m / s. The method has the advantages of realizing low-cost short-process near-net shape forming, along with simple process, high practicability and low cost. Compared with the neodymium iron boron magnet, the produced neodymium iron boron magnet has the advantages that the green body density is increased by 0.43 to 0.93 g / cm<3>, the remanence is increased by 0.2 to 0.54 T, the maximummagnetic energy product is increased by 20 to 60 kJ / m<3>, the coercive force Hcb is increased by 73 to 348 kA / m and Hci is increased by 80 to 387 kA / m.

The invention discloses a method for preparing a high-performance permanent magnet ferrite. The steps are: (1) batching: mixing the main component and a primary additive; (2) mixing: mixing the prepared raw materials through dry mixing (3) pelletizing: pelletize the mixture to obtain pellets with a diameter of 5-12 mm; (4) pre-sintering: sinter the pellets at 1290-1390°C for 1.5-2.5 hours to obtain pre-sintered pellets; (5 ) Secondary grinding: After crushing the calcined material into coarse powder, it is mixed with secondary additives and wet ball milled to obtain fine slurry. The secondary additives include calcium carbonate, silicon dioxide and clinker calcined powder; (6) Sintering: the fine slurry is wet-pressed and then sintered to obtain the high-performance permanent magnet ferrite. The invention uses a dry process to mix materials, which reduces the cost of the process, and adds clinker pre-calcined powder to the secondary additive to obtain a permanent magnet oxide with high remanence, intrinsic coercive force and maximum magnetic energy product. body.

An explosion method for shaping the adhered dual-phase nano-crystalline anisotropic NdFeB magnet includes such steps as loading the isotropic NdFeB magnet powder in sleeve steel cylinder, treating by magnetic field, fixing the sleeve steel cylinder onto base with an explosive tube on it, filling explosive in the tube, and exploding. Its advantages are high density and high magnetic performance.