Method for producing high-coercivity magnets from alloys on basis of nd-fe-b

FIELD: metallurgy.

SUBSTANCE: invention can be used for production of high-energy permanent magnets based on rare-earth-alloys (rare earth metals), and alloys, in particular, based on neodymium, iron and boron (Nd-Fe-B alloy). The method for production of high-coercive magnets from Nd-Fe-B-based alloys includes crushing the base alloy, mixing the alloy and an additive for correction of alloy composition, pressing a mixture of powders in magnetic field, sintering the blank and cooling. The additive for correction of alloy composition is hydrides of rare-earth metals-Fe, and sintering of magnet is carried out in vacuum or at residual pressure for 1-2 h.

EFFECT: invention makes it possible to increase coercive force and residual induction of produced magnets.

2 cl, 2 dwg

 



 

Same patents:

FIELD: chemistry.

SUBSTANCE: sulphinic acid is used as surfactant with the following ratio of components, wt %: fine particles of iron-bearing oxide compound 70-90, benzene sulphinic acid - the balance.

EFFECT: obtaining a dry concentrate of a magnetic liquid with a long shelf life.

2 cl, 3 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: group of inventions relates to a process of producing organic substrate particles bonded to switchable ferromagnetic nanoparticles with a mean particle diameter ranging from 10 to 1000 nm, to the use of such nanoparticles for hyperthermic treatment of an organism and to a drug for the hyperthermc treatment. As the ferromagnetic nanoparticles used are nanoparticles, which are non-ferromagnetic at first, but become ferromagnetic when the temperature is lowered, these initially non-ferromagnetic dispersed nanoparticles are bonded to the organic substrate particles, and then the nanoparticles bonded to the substrate particles become ferromagnetic as a result of the temperature decrease, initially the switchable ferromagnetic nanoparticles at the temperature of 22°C or higher are not ferromagnetic and become ferromagnetic as a result of cooling down to the temperatures below 22°C. The switchable ferromagnetic nanoparticle comprises Mn and additionally Fe and/or As and preferably have the Fe2P-structure or Na-Zn-13-structure, alternatively, or may comprise La, Fe and Si.

EFFECT: invention prevents the agglomeration of particles and an increase in the mean particle size.

10 cl, 1 dwg, 2 ex

FIELD: chemistry.

SUBSTANCE: invention can be used in producing magnetic powders, permanent magnets, resin-bonded magnets, magnetic liquids and high-density magnetic recording devices. The method of producing barium hexaferrite includes preparing a barium hexaferrite suspension, depositing said suspension in a neutral or weakly alkaline medium and drying. The barium hexaferrite suspension is obtained using an electrochemical method by dissolving electrodes made of steel St3, the distance between which is 5-15 mm, in an electroconductive solution of barium hydroxide and sodium chloride. The process is carried out with concentration of Ba(OH)2 7-10 mg/dm3, NaCl 3-5 mg/dm3, voltage 8-10 V, temperature 85-90°C, current density 0.11 A/cm2.

EFFECT: invention simplifies production of fine barium hexaferrite powder.

1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: electric steel sheet roll after cold rolling is exposed to primary recrystallisation annealing, an annealing separator is applied on it, and final annealing is performed. Heating of the roll for the primary recrystallisation annealing is carried out with a speed of at least 80°C/s from 500°C to 700°C in the process of heating, and during heating for final annealing, exposure is carried out from 2 to 100 hours at a temperature from 700°C to 1000°C. Final annealing of the roll is carried out in an annealing furnace, at the same time a heat insulation material is laid onto the upper surface of the stand supporting the roll, concentrically from the external periphery of the stand supporting the roll, and in the area of at least 20% of the radius of the stand supporting the roll.

EFFECT: elimination of sheet shape defects produced from final annealing and an increased yield of finished goods.

3 cl, 5 dwg, 1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to powder metallurgy. A method for obtaining a magnetically soft material for magnetic conductors of relays involves preparation of charge containing iron and phosphorus, its pressing, sintering and cooling. Charge is prepared by introduction to powder of iron, which contains not more than 0.03 wt % of carbon and not more than 0.15 wt % of oxygen, phosphorus in the form of a solution of orthophosphoric acid H3PO3 or a powder of ferrophosphorus so that content of phosphorus in the mixture is provided in the amount of 0.5-1.5 wt %. Charge sintering is performed in vacuum of 10-1-10-3 Pa at the temperature of 1320-1380°C with exposure at this temperature within 1.5-4.0 hours.

EFFECT: reduction of a coercitive force, improvement of magnetic permeability and saturation induction.

10 cl, 6 dwg, 1 tbl, 6 ex

FIELD: metallurgy.

SUBSTANCE: invention relates to application on the textured electric flat steel of the phosphate coating. Under method to the electrical flat steel the phosphate solution is applied, it contains at least one chrome (III) composition, colloidal component, and at least one compound ether of phosphoric acid as stabiliser (A) of the colloid and/or at least one etching inhibitor (B) selected from the derivative of thiourea, C2-10-alkynol, derivative of triazine, thioglycolic acid, C1-4-alkylamine, hedroxy-C2-8-thiocarboxylic acid and/or polyglycol ether of fatty alcohol, in particular diethyl sulphourea, prop-2-in-1-ol, butyn-1,4-diol, thioglycolic acid, and/or hexamethylenetetramine, at that phosphate solution is used, hexavalent chrome content in it is below 0.2 wt %.

EFFECT: invention produces the phosphate layer on the textured electric flat steel having properties identical to properties of chrome (VI) containing insulation coating, and having improved optical properties and increased tension stress.

13 cl, 17 dwg, 10 tbl, 7 ex

FIELD: metallurgy.

SUBSTANCE: cast flat billet containing C below 0.02 wt % is subjected to hot rolling at temperature equal to A3 temperature or above. Then rolling in α-area is performed at temperature 300°C or above and below A3 temperature with manufacturing of the base metal plate with structure {100} in part of the surface layer. Then by heat treatment under specified conditions the metal plate is manufactured, in which for intensities ratio of the appropriate stresses {001}<4 7 0>, {116}<6 12 1> and {223}<6 9 2> in the plate plane as per X-ray diffractogram designated as A, B and C, respectively the condition Z=(A+0.97B)/0.98C is met, where Z is at least 2.0 and 200 maximum.

EFFECT: energy losses decreasing upon decreasing of the magnetic cores dimension.

15 cl, 5 dwg, 11 tbl, 4 ex

FIELD: metallurgy.

SUBSTANCE: insulation coating is obtained as a result of application of a surface treatment agent at least to one side of electrical sheet steel and drying of the surface treatment agent. The surface treatment agent contains trialkoxysilane and/or dialkoxysilane (A), in which a substituent fixed with Si is formed only with at least one nonreactive capable substituent chosen from a group consisting of hydrogen, an alkyl group and a phenyl group; and a silane binding agent (B) at weight ratio of (A/B) in the range of 0.05 to 1.0.

EFFECT: providing excellent formability, an adhesive ability of the coating, properties of the coating film after annealing, weldability at gas-tungsten welding, corrosion resistance and resistance to pressure slides even without any content of any chrome compound in an insulation coating.

4 cl, 4 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to ferromagnetic powder composition and method of its obtaining. Claimed is ferromagnetic powder composition, including iron-based soft magnetic particles of core, which have bulk density 3.2-3.7 g/ml, with the surface of core particles being provided with inorganic insulation phosphorus-based layer and at least one organometallic layer of organometallic compound of claimed structure, located outside first inorganic insulation phosphorus-based layer. Disperse bismuth oxide is linked with organometalic layer. Invention also relates to method of composition obtaining and method of manufacturing soft magnetic materials, prepared from claimed composition as well as to material obtained.

EFFECT: claimed composition makes it possible to obtain materials with high specific resistance and low loss in core in environmentally friendly way.

18 cl, 7 tbl, 7 ex

FIELD: machine building.

SUBSTANCE: invention relates to the electrical machine building, and can be used to manufacture the magnetic-dielectric material in form of sheets or plates to produce the magnetic wedge of the electrical machines. The ferromagnetic component, epoxy resin and curing agent are mixed, the obtained mass is poured in the die mould with reinforcement element in form of the glass fibre fabric, and then treatment by the magnetic field is performed during pressing. The ferromagnetic component is added in form of the nano size particles of ferriferrous oxide with size up to 100 nm, and magnetic field is applied with intensity at least 800 oersted to the magnetic-dielectric mass with preliminary determined degree of solidification max. 30%.

EFFECT: material is manufactured for the magnetic wedge production ensuring decreasing of the additional motor losses and ensuring required magnetic permittivity.

2 dwg, 2 ex

FIELD: metallurgy.

SUBSTANCE: charge is prepared containing metal components of specified composition of the pseudoalloy by their mixing, the prepared charge is pressed. Billet is annealed in vacuum at pressure 1.33×10-2 Pa maximum, at temperature 300°C minimum and not exceeding melt temperature of low-melting component of the pseudoalloy for at least 1 h. Pseudoalloy billet is sintered in hydrogen atmosphere by two stages. At the first stage heating to temperature 800°C minimum is performed, at the second stage - to sintering temperature of specified charge with holding at these temperatures for at least 1 h, respectively. After sintering additionally axial pressing of the pseudoalloy billet is performed at pressure decreasing from 300 MPa to 80 MPa with rate 80 MPa/min max.

EFFECT: increased electrical conductivity and thermal conductivity of the composite material due to increasing of its homogeneity and reduction of temperature coefficient of linear expansion upon keeping high limit density.

2 cl, 1 tbl, 6 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to powder metallurgy. A method for obtaining a magnetically soft material for magnetic conductors of relays involves preparation of charge containing iron and phosphorus, its pressing, sintering and cooling. Charge is prepared by introduction to powder of iron, which contains not more than 0.03 wt % of carbon and not more than 0.15 wt % of oxygen, phosphorus in the form of a solution of orthophosphoric acid H3PO3 or a powder of ferrophosphorus so that content of phosphorus in the mixture is provided in the amount of 0.5-1.5 wt %. Charge sintering is performed in vacuum of 10-1-10-3 Pa at the temperature of 1320-1380°C with exposure at this temperature within 1.5-4.0 hours.

EFFECT: reduction of a coercitive force, improvement of magnetic permeability and saturation induction.

10 cl, 6 dwg, 1 tbl, 6 ex

FIELD: metallurgy.

SUBSTANCE: method involves the application of the first powder material and selective sintering in the specified sections of the layer. The first powder material is removed from non-sintered sections. To the space between the sintered sections of the layer of the first powder material there applied is a layer of the second powder material of the same thickness and it is selectively sintered in the same sections. The specified cycles are repeated till the full formation of a workpiece of the product. As the first powder material there used is a dielectric material forming (at sintering) a casting mould of the product being formed. As the second powder material there used is powder from a metal or an alloy of the product being formed. At application of the second powder material, the product being formed is used as an anode and between the product being formed and a laser nozzle electrode there excited is a pulse electric arc. After the full formation of the product workpiece its fusion and further crystallisation is performed in the formed casting mould.

EFFECT: improvement of the method.

11 cl, 3 dwg

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, in particular to methods of parts manufacturing by additive sintering. Method of part manufacturing is suggested based on Co-Cr-Mo alloys having average ultimate elongation at 800°C and higher over 10% and average yield strength at 800°C over 400 MPa. Method includes the sintered part manufacturing by the additive sintering of the alloy powders based on Co-Cr-Mo, two heat treatments with intermediate cooling.

EFFECT: brittleness of the manufactured parts is reduced, plasticity and yield strength at high temperatures increase.

6 cl, 3 dwg, 3 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to ferromagnetic powder composition and method of its obtaining. Claimed is ferromagnetic powder composition, including iron-based soft magnetic particles of core, which have bulk density 3.2-3.7 g/ml, with the surface of core particles being provided with inorganic insulation phosphorus-based layer and at least one organometallic layer of organometallic compound of claimed structure, located outside first inorganic insulation phosphorus-based layer. Disperse bismuth oxide is linked with organometalic layer. Invention also relates to method of composition obtaining and method of manufacturing soft magnetic materials, prepared from claimed composition as well as to material obtained.

EFFECT: claimed composition makes it possible to obtain materials with high specific resistance and low loss in core in environmentally friendly way.

18 cl, 7 tbl, 7 ex

FIELD: metallurgy.

SUBSTANCE: invention relates to the powder metallurgy, namely to the sintered hard alloys, and can be used to manufacture tools. The method of production of sintered hard alloys based on tungsten carbide containing cobalt and nanosize particle of aluminium oxide means preparation of the alloy charge mixture, plastification, granulation, pressing and sintering. The alloy charge mixture is prepared by preliminary mixing of the aluminium oxide in water solution of polyvinyl alcohol by the ultrasound dispersion until suspension production, grinding-mixing of the suspension with grains of the tungsten carbide till creation on its surface of the clad layer, charge addition by cobalt, and further mixing. Plastification is performed in water solution of the polyvinyl alcohol.

EFFECT: increased strength of the hard alloy due to assurance of the more uniform distribution of the nanosize particles over volume of the hard alloy structure.

1 tbl

FIELD: metallurgy.

SUBSTANCE: invention refers to powder metallurgy. A method for obtaining ferrite items involves preparation of moulding powder containing ferrite material and an alloying additive, pressing of workpieces, radiation thermal sintering of workpieces by their heating to temperature of sintering by irradiation with a penetrating electron beam with exposure at the temperature under irradiation with a continuous electron beam. As an alloying additive to the moulding powder there added is nanosized powder of carbonyl iron with particle size of 320-450 nm in the amount of 0.01-0.03 wt % of total weight of the moulding powder.

EFFECT: improvement of a sintering process, reduction of sintering time and improvement of quality of ferrite items.

8 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: charge is prepared, which contains iron and phosphorus; then, it is pressed, sintered and cooled down. Sintering is performed in vacuum of 10-1-10-3 Pa at the temperature of 1320-1380°C; after that, exposure is performed at the specified temperature during 1.5-2.5 hours and cooling is performed to the temperature of 450-600°C. Sintering, exposure and cooling is repeated cyclically so that the required characteristics of soft magnetic material are obtained. Charge can be prepared by introduction of phosphorus to iron powder in the form of 10% of the solution of orthophosphoric acid in ethyl alcohol or in the form of ferrophosphorus powder.

EFFECT: reduction of coercitive force; increase of magnetic permeability and induction of saturation due to creation of uniform granularity of material and spheroidisation of pores.

12 cl, 3 dwg, 1 tbl, 3 ex

FIELD: process engineering.

SUBSTANCE: invention relates to powder metallurgy and can be used for fabrication of hard alloy end tool, Tungsten carbide ultrafine powder with particle size of 50-100 nm is added in amount of 2-5% of the article weight to tungsten carbide-based alloy with particle size of 1-3 mcm. This powder is compacted and annealed.

EFFECT: microstructure grain homogenisation, higher surface finish, ruled out mechanical surface finishing.

3 dwg, 1 ex

FIELD: metallurgy.

SUBSTANCE: invention relates to magnetic material containing praseodymium, iron, cobalt, boron, copper and at least one element chosen from a group of gadolinium (Gd), dysprosium (Dy), samarium (Sm), and cerium (Ce). In addition, material contains zinc (Zn). Chemical composition of the material corresponds to the following formula, atm %: (Pr1-x1-x2R1x1R2x2)11.5-16(Fe1-y1Coy1)rest(ZnzCu1-z)y2B6-20, where R1 - at least one element chosen from the group of Gd, Dy, R2 - at least one element chosen from the group of Sm, Ce; x1=0.20-0.50; x2=0.01-0.25; y1=0.30-0.55; y2=0.1-3.0; z=0.001-0.1. Besides, an item made from the above magnetic material is proposed.

EFFECT: increasing the yield ratio of ring-type magnets with a radial texture with high temperature stability of magnetic properties and improving coercitive force HCI of magnetic material.

2 cl, 1 tbl

FIELD: powder metallurgy, in particular electric contact materials.

SUBSTANCE: invention relates to carbon-copper composite. Material is produced from copper powder having purity of 99.9 % and black carbon powder with particle size at most 5 µm. Copper matrix has grid structure with through pores. One part of pores contains black carbon providing microstructure with carbon constituents. Parameter according to "International standard for annealed copper" is at least 40 %; density is at least 6.0 g/cm3. Copper powder is purified and annealed followed by blending of carbon and copper powders, double-side pressing under 500-1600 MPa, and sintering at 960-11000C.

EFFECT: material with increased density and conductivity and enhanced durability.

20 cl, 1 dwg, 7 tbl

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