47results about How to "Good coercivity" patented technology

A hard bias (HB) structure for longitudinally biasing a free layer in a MR sensor is disclosed that includes a mildly etched seed layer and a hard bias (HB) layer on the etched seed layer. The HB layer may contain one or more HB sub-layers stacked on a lower sub-layer which contacts the etched seed layer. Each HB sub-layer is mildly etched before depositing another HB sub-layer thereon. The etch may be performed in an IBD chamber and creates a higher concentration of nucleation sites on the etched surface thereby promoting a smaller HB average grain size than would be realized with no etch treatments. A smaller HB average grain size is responsible for increasing Hcr in a CoPt HB layer to as high as 2500 to 3000 Oe. Higher Hcr is achieved without changing the seed layer or HB material and without changing the thickness of the aforementioned layers.

The invention discloses a method of improving the coercivity of sintering Nd-Fe-B magnetic materials. The method includes the following steps of using hydrogen to crush Nd-Fe-B alloy, powder processing, compression moulding, sintering and tempering under the protection of vacuum or protective gases. The sintering condition consists of heating to 300 to 600 DEG C, keeping the temperature for 5 to 6 hours to dehydrogenize, heating once again to 1060 to 1120 DEG C, sintering for 1 to 60 minutes under high temperature, finally decreasing the temperature to 1000 to 1050 DEG C, keeping sintering for 1 to 4 hours under the temperature and cooling. The method adopts the steps of sintering for a short period under high temperature to precipitate the liquid phase and then sintering under lower temperature. The liquid phase is rapidly precipitated under high temperature, thereby improving the sintering process of the magnetic materials, promoting the performance of sintering process, controlling the grain size through sintering under lower temperature, inhabiting grain growth and benefiting obtaining an excellent coercivity of magnetic materials.

The invention relates to a treating agent and an electro-deposition method for forming a rare earth hydride particle coating, and belongs to the technical field of magnetic materials. Rare earth hydride particles are dispersed in a dispersing agent, wherein n-hexane or n-heptane is taken as the dispersing agent; the rare earth is at least one element of Pr, Nd, Tb, Dy and Ho. The hydride particles are deposited on the surface of a sintered NdFeB rare earth magnet by using the electro-deposition method so as to form the uniform and dense coating with controllable thickness. The rare earth hydride particle coating can be used for obviously improving the magnetic property of the sintered NdFeB rare earth magnet and especially the coercivity of the magnet. As the method is adopted, the usage amounts of heavy rare earths in the sintered NdFeB rare earth is decreased on the premise of guaranteeing good magnetic property of the magnet, so that the manufacturing cost of the magnet with high coercivity is reduced.

An epitaxial growth method of a yttrium iron garnet film comprises the following steps: vacuumizing a vacuum cavity with a treated yttrium iron garnet substrate to be 8.6+ / -1*10-6 Pa, and heating the yttrium iron garnet substrate to the constant temperature which is 736 DEG C; in a heating process, feeding ozone when heating to the temperature of 250 DEG C; after heating to the temperature of 736 DEG C, maintaining air pressure of the vacuum cavity, adjusting the mass fraction of the ozone to be 40%, meanwhile insulating for half a hour, and starting a reflective high-energy electron diffraction instrument (RHEED) to adjust so as to obtain diffraction spots of a substrate; maintaining real-time and in-situ monitoring of the RHEED in the whole process, and focusing laser onto a YIG target through a lens by using a KrF excimer laser of which the wavelength is 248 nm; after growth of the film is finished, maintaining the temperature of the substrate unchanged, annealing in situ for 15 minutes, then naturally cooling the film to the temperature about 250 DEG C, stopping protective gas and cooling to the room temperature. The obtained YIG film has uniform components, is controllable in thickness and good in process repeatability, and has high preparation efficiency.

The invention discloses an R-T-B-based magnetic material, which is characterized in that, in terms of weight percentage, it comprises the following components: 27.42wt.% to 33.00wt.% of R; the R is a rare earth element , which contains Pr and R H ; said Pr≥15.00wt.%; said R H Contains Tb and / or Dy; 0.24wt.% to 0.80wt.% Cu; 0.19wt.% to 0.30wt.% Zr; 0wt.% to 1.52wt.% Al; 0.90wt.% to 1.03wt. % B; and, 0.04 wt.% to 0.09 wt.% Ga or 0.28 wt.% to 1.50 wt.% Ga. The magnetic material has better remanence, coercive force, temperature coefficient, etc.

The invention discloses a neodymium iron boron material, a preparation method and application thereof. The raw material composition of the NdFeB material includes the following components in mass content: R: 28.5-34%; R is a rare earth element, and R includes Nd; B: 0.84-0.94%; Cu: 0.45%

The invention discloses a method for preparing a soft magnetic alloy bar. A high-strength soft magnetic alloy is prepared by optimizing the chemical composition and process. The mass percentages of each component are: C≤0.04%, Si≤0.30%, Mn≤ 0.30%, P≤0.020%, S≤0.020%, Cu≤0.20%, Ni≤0.50%, Co is 48.0~51.0%, V is 1.80~2.10%, Mo is 0.1~0.2%, Fe is the balance; preparation The process includes: vacuum smelting, casting alloy ingots, forging blanks, hot-rolled finished products, and solution treatment. The high-strength soft magnetic alloy rod 1J22MV prepared by the present invention has a tensile strength greater than 500MPa; yield strength ≥ 250MPa; B800 ≥ 1.8T, B2400 ≥ 2.1T, B4000 ≥ 2.15T, B8000 ≥ 2.2T; coercive force Hc ≤144A / m; Curie point 980°C; saturation hysteresis coefficient (10 ‑6 ) 60~100.

An R-T-B based permanent magnet includes R-T-B based compounds as main-phase crystal grains. R is a rare earth element. T is iron group element(s) essentially including Fe or Fe and Co. B is boron. A two-grain boundary is contained between the two adjacent main-phase crystal grains. An average grain size of the main-phase crystal grains is 0.9 μm or more and 2.8 μm or less. A thickness of the two-grain boundary is 5 nm or more and 200 nm or less.

This application relates to the technical field of NdFeB magnetic materials, and specifically relates to a preparation method of NdFeB magnetic materials, including melting and stripping, hydrogen crushing and grinding, compression molding, raw magnetic sheeting, rare earth pulping, coating slurry and The preparation steps of diffusion sintering can effectively promote the diffusion of heavy rare earth elements such as dysprosium and terbium in the crystalline phase, and at the same time inhibit their diffusion into the main phase grains, improve the effective utilization of heavy rare earth elements such as dysprosium and terbium, and greatly Improve the coercive force of NdFeB magnets.