50results about How to "Lower nitriding temperature" patented technology

The invention relates to a stainless steel ion nitriding process, and in particular relates to an austenitic stainless steel ion nitriding permeation catalyzing process. The process mainly comprises the following steps: 1) washing the surface of a stainless steel surface, and removing the oil stain and impurities on the surface of the workpiece; 2) carrying out pre-oxidation treatment on the stainless steel workpiece; 3) putting the stainless steel workpiece into an ion nitriding furnace after being cooled down, introducing dried hydrogen, building up of luminance and heating up, after reaching a certain temperature, introducing nitrogen, adjusting the ratio of the nitrogen to the hydrogen and the pressure in the furnace, subsequently starting to time, after nitriding for a certain time, closing the ion nitriding furnace and cooling down the workpiece along with the furnace. The austenitic stainless steel treated by using the process can obtain a compound layer which is thicker than that of an ordinary ion nitriding process.

The invention discloses an ion nitriding method for titanium alloy, and relates to the technical field of surface treatment. The method comprises the steps that a workpiece is placed in a plasma nitriding furnace, nitriding gas is introduced, the nitriding voltage is controlled to range from 500 V to 700 V, the temperature in the plasma nitriding furnace is controlled to slowly rise to 750 DEG C to 950 DEG C, the air pressure ranges from 500 Pa to 1500 Pa, and heat preservation is carried out to obtain a required nitriding layer thickness; and the nitriding gas comprises nitrogen-containing gas, hydrogen, argon and a permeation accelerant, and the permeation accelerant comprises at least one of rare earth oxide, oxygen-containing gas and carbon-containing gas. The nitriding method has thecharacteristics of high nitriding speed, capability of reducing the nitriding temperature, thick nitriding layer, high hardness, good wear resistance and small workpiece deformation.

The invention discloses a preparation method of nitrogen-contained rear earth magnetic powder which takes dicyclopentadienyl iron, alum rare earth, metallic iron and rare earth as main raw materials and has the main component of R2Fe(17-x)MxNy, wherein R stands for one or several of 17 rear earth elements containing Sc and Y; M is one or a plurality of transition elements of Al, Ga, In, Si, Ge, Sn, Pb, Mg and Ca except Fe; x=0-5 and y=1-6. The preparation method comprises the following steps: preparation process of R2Fe(17-x)Mx alloy casting; nitridation process; and milling process.

The invention discloses a low-temperature nitridation preparation method of iron-based rare earth permanent magnet powder. The method is characterized in comprising the steps that: (1) under Ar gas protection, Sm2Fe17 alloy is smelted by using pure samarium and pure iron in a vacuum induction furnace, such that an ingot is obtained; the ingot is subjected to a homogenization treatment, and is crushed into powdery particles with an average particle size smaller than 40mun; (2) a surfactant, grinding balls and the powdery particles are added into a ball milling tank; a ball milling medium is filled into the tank; and with the cooperation of the surfactant and high-energy ball milling, flaky powder with a nano-crystalline structure is obtained, wherein the surfactant is coated on the surface of the powder; (3) the powder is filtered, such that the ball milling medium is removed; and the powder is subjected to vacuum drying; and (4) the powder is subjected to a nitridation treatment under a low temperature of 300-400 DEG C. The microstructure of the obtained permanent magnet powder is nano-crystals with grain sizes of 8-20nm. The nano-sheet thickness is approximately 5-200nm, Hc is 5-14kOe, and (BH) max is 10-28MGOe. On the basis that an original structure and advantages are maintained, the nitridation temperature is greatly reduced. The nano-sheet powder can be prepared into a high-performance bonding magnet which can be used in fields such as motors and engines.

The invention discloses a preparation method of a samarium-iron-nitrogen series permanent magnet material. The method comprises the steps that metastable state samarium-iron alloy is subjected to severe plastic deformation and then is subjected to nitrogen treatment and annealing crystallization treatment, and therefore the samarium-iron-nitrogen series permanent magnet material can be obtained. In the method, when the deformed samarium-iron-nitrogen series permanent magnet material is subjected to nitrogen treatment, since the free volume 'defect' content in the metastable state alloy can beincreased through multiple shear bands produced in the severe plastic deformation process, entering and diffusion of nitrogen atoms are facilitated, and the nitriding amount and nitriding uniformity of the alloy can be remarkably improved; since the multiple shear bands are produced through the severe plastic deformation, the follow-up crystallization annealing temperature can also be reduced, andnitride is reduced or prevented from being produced; and generation of the metastable phase is restrained, grains are refined, and coercive force is improved. By means of the method, the nitriding speed can be improved, the nitriding temperature can be reduced, decomposition of a samarium-iron-nitrogen compound is restrained, the microstructure is refined, and the nitriding efficiency of samarium-iron alloy for preparing the samarium-iron-nitrogen magnetic material is improved.

The invention discloses a preparation method for a zirconium nitride-coated lithium titanate composite material, relating to the field of a negative electrode material of a lithium ion battery. The preparation method comprises the steps of preparing lithium titanate precursor powder, performing high-energy ball grinding on zirconium powder, a lithium titanate precursor and an additive under inert atmosphere, and finally performing high-temperature sintering under nitrogen mixing atmosphere to realize synthesis of lithium titanate and nitridation reaction of surface zirconium. According to the zirconium nitride-coated lithium titanate composite material prepared by the preparation method disclosed by the invention, the zirconium nitride coating layer is high in uniformity, good in coating effect and high in conductivity; the problem of low conductivity of lithium titanate is solved; meanwhile, the problem of swelling of a battery of the lithium titanate system is effectively solved; the circulation stability of a lithium titanate negative electrode material is improved, and the cycle life of the battery is greatly prolonged; furthermore, the preparation process of the preparation method is simple and controllable; the coating degree of the zirconium nitride can be controlled by controlling technical parameters for preparing the zirconium nitride-coated lithium titanate composite material.

The invention relates to a method for preparing aluminum nitride powder. The method for preparing the aluminum nitride powder comprises the following steps that pseudo-boehmite gel, an inorganic carbon source, a water-soluble organic carbon source and a sintering agent are mixed, and a mixture is obtained; in a nitrogen atmosphere, the mixture is nitrogenized at the temperature of 1,250 DEG C to 1,700 DEG C, and a reduction product is obtained; under the aerobic condition, the reduction product is calcined for 3-10 hours at the temperature of 600 DEG C to 720 DEG C, and the aluminum nitride powder is obtained. The aluminum nitride powder prepared through the method is high in purity.

The present invention relates to a preparation method for CaSi2O2N2:Eu<2+> fluorescence nano-fiber. The method comprises the following steps: (1) dissolving calcium nitrate and europium nitrate in a mixed solvent comprising alcohol and water; adding tetraethyl orthosilicate while stirring; adding polyvinylpyrrolidone after stirring; continuously stirring to obtain a spinning liquid; (2) pouring the spinning liquid into a syringe, carrying out electrostatic spinning to collect a layer of uniform white fiber on receiving aluminum foil; (3) placing the white fiber into a high-temperature tubularatmosphere furnace to carry out a heat treatment; finally carrying out cooling along with the furnace to obtain the CaSi2O2N2:Eu<2+> fluorescence nano-fiber. The method of the present invention has characteristics of simpleness, low nitridation temperature and short time. The prepared CaSi2O2N2:Eu<2+> phosphor has good fiber morphology so as to contribute to improvement of the luminescent property and the later package in the LED, and has a good application prospect.

The invention relates to a preparation method of a green AIN:Tb fluorescent powder material. The preparation method comprises following steps: S1), aluminum powder, magnesium powder, ammonium chlorideand terbium powder are sufficiently mixed by grinding, the mixture is transferred into an alumina ceramic ark, and reaction precursor powder is obtained; S2), the alumina ceramic ark is transferred into a tube type resistance furnace, nitrogen gas is introduced for nitrogen treatment, and the green AIN:Tb fluorescent powder material is obtained by thermal insulation and cooling. The preparation method has the advantages that the preparation process is simple, the preparation cost is low, the nitriding temperature is low and the material has good performance, high purity, small particles anduniform particle size, the nitridation rate of a product is increased by adding magnesium powder and ammonium chloride as catalysts, nitridation can be realized at a lower temperature, and the preparation process is high in controllability and convenient to implement; the green AIN:Tb fluorescent powder material has the characteristic of green fluorescence property, a sample is subjected to crystal phase analysis through X-ray diffraction, and a diffraction peak is free of impurity phase and is relatively sharp.