Compositional ferroabrasive powder and method for obtaining same

FIELD: chemistry.

SUBSTANCE: making of compositional ferroabrasive powder includes mixing of the wet ferromagnetic powder component (iron powder) with dried at temperature 80-120°C adhesive structure-forming component - powder of nanocrystall aluminium hydroxide γ-AlOOH. Then abrasive powder component (diamond powder) and binding component are added. The mixture is agitated up to obtaining of homogenous structure and heated up to temperature of composition dehydratation - 290-350°C. Ferroabarsive compositional powder with desired particle size is formed by its rubbing through corresponding calibrated sieves. Ferroabrasive composite powder components have the following volume ratio: ferromagnetic component - 30-65%, adhesive -forming component - 30-40%, abrasive component up to 15%, binding component - the rest.

EFFECT: quality improvement of processed surfaces alongside with increase of material removal intensity, increase of abrasive processing speed, decrease of the working zone temperature.

7 cl, 1 tbl, 1 ex

 

The invention relates to powder metallurgy, in particular to the creation of a ferro-abrasive powders as powders tools by magnetic abrasive finishing of surfaces.

Abrasive materials are the main field of application of refractory compounds. Having a high hardness, strength and chemical resistance, these powders meet the requirements of abrasives, provide abrasive machining of high performance, clean the machined surfaces, the minimum accumulation of stresses on the surface and in the volume of the processed material as by grinding and polishing [see Adamsky A.A. Abrasive materials of the refractory metal-like compounds. // Powder metallurgy, 1974, No. 5, 49-56; Samsonov, G.V. New abrasives for grinding and finishing. // Powder metallurgy, 1973, No. 7, p.72-82].

The main indicators of abrasive material is abrasive ability, durability grain compression, the roughness of the processed materials.

Known synthetic abrasive grains obtained in the process of melting, when ceramic materials are melted in a furnace, and then cooled slowly to obtain a solid clinker [U.S. patent No. 4,685,937 (Hori et al.), MCI SW 35/65, 1987], or fast shipped is eaten in water to obtain small crystals [U.S. patent No. 5,009,676 (Rue et al.), MCI SW 35/111, 1991].

In recent years, the abrasive grain prepared using different Sol-gel processes. In the Sol-gel process, hydrated forms of aluminum oxide (i.e. γ-lOO or boehmite) is usually mixed with water and acid to obtain a colloidal dispersion or Sol. Colloidal dispersion of γ-lOO dehydrated to produce the grain particles of the precursor, which is typically made red-hot and then is sintered. During annealing γ-lOO is converted into the intermediate oxide (oxides) of aluminum. At the stage of sintering the intermediate oxide (oxide) aluminium beans particles is converted to alpha-alumina, which is then compacted. Such Sol-gel processes are described in U.S. patents: No. 4,314,827 (Leitheiser et al.), MCI SC 3/14, 1982; No. 4,770,671 (Monroe et al.), MCI B24D 3/34, 1988; No. 5,164,348 (Wood) MCI SW 35/624, 1992 and No. 5611829 (Monroe et al.), MCI C04B 35/111, 1997.

Aluminum hydroxide γ-lOO is a key component in these processes, since it can be obtained in the form of a substance of high purity, its particles are of submicron size and it easily forms a colloidal dispersion.

However, there are alternative methods of creating ceramic abrasive grains on the basis of alpha-aluminum oxide.

One such alternative methods [U.S. patent No. 4,685,937 (Hori et al.), MCI C04B 35/65, 1987] is the magnetic-abrasive grinding. In accordance with this% is Scam product and magnetic abrasive particles, sensitive to magnetism, are placed between the magnetic poles, where the magnetic abrasive particles fall into dependence on the magnetic field. The component is subjected to rotation or vibration, while the abrasive particles are held by the magnetic field and have no abrasive effect. Magnetic abrasive particles used in this method must have ferromagnetism and high hardness. Usually they are a composite of iron and the material high hardness, such as aluminum oxide, titanium carbide, etc. Known methods of preparing such composite connections: the process in which finely ground particles of iron and hardened materials are sintered in a furnace after pressure molding or during hot pressing; the process by which alloy metals and carbon to form a carbide, as well as the process by which the exothermic reaction between carbon and titanium is formed composite of titanium carbide and iron. In any of the above-described processes for creating a magnetic abrasive particles of the appropriate size of the composite material assumes its sintering and fragmentation.

The sintering processes require expensive furnace. In addition, there are significant difficulties with the fragmentation of the composite, resulting from such is the procedure until the desired particle size. The process of internal nitriding of metals or process of making abrasive particles of the alloy requires expensive equipment and is not a high yield. Thus, these processes are not economical. In addition, the crushing of materials of high hardness is extremely difficult and it is impossible to obtain a finely milled particles.

Also known is a method of obtaining abrasive micron size crystals from 0.2 to 2 μm on the basis of oxides of aluminum and iron [RF patent №2212425 (Kleschev, and others), MKI C09G 1/02, 2003], which includes the stage of preparation of the mixture of hydroxides of aluminum and iron compounds, followed by mechanochemical processing and calcining the mixture. When aluminum hydroxide is subjected to a preliminary heat treatment at a temperature of 100-250°C, and at the stage of mechanical activation in charge is injected additive carboxylic or dicarboxylic acids in an amount of 0.1-5.0 wt.%, and as carboxylic use stearic or benzoic acid as a dicarboxylic - oxalic, succinic or phthalic acid. The disadvantages of this method are its relative complexity, the use of a wide variety of components, and necessary, calcining the mixture, which entails that have already been specified above disadvantages of the sintering process.

Also known [see, Eaarl, L.krul, Gevgelija,Neshanic, Applicance "Study of abrasive ability ferro-abrasive powders obtained by different methods, composite materials in industry". / Proceedings of the 25th Anniversary conference and exhibition, Yalta, 2005, s.138-139/.] ferro-abrasive powders tools based on iron and carbides of transition metals Ti, W, V, etc. of These materials are successfully used for polishing and deburring of metals and alloys by micro-80-600 MPa. The surface is polished with powder particles are pressed against it by the magnetic field when moving the powder and the surface of the parts relative to each other. This treatment reduces the surface roughness at 4-5 classes, does not create prizhogi and microcracks [see Magnetic-abrasive materials and methods of their testing. - Kiev, 1980; Powder materials for magnetovariational processing. - Powder metallurgy, 1976, No. 12, p.63-69]. However, ferro-abrasive powders-based tools and iron carbides ineffective when polishing, the highly rigid (1000-1600 MPa) silicon and glass.

The closest in technical essence and the achieved result of the present invention is U.S. patent No. 5846270 (Feygin, et al.), MCI C09C 001/68 (prototype), which for magnetic abrasive polishing of the proposed composite ferro-abrasive powders consisting of ferromagnetic base (iron or its alloy is s) on the surface of which is divided diamond grains. In the process of manufacturing the magnetic-abrasive powder in accordance with this patent, there is no need in high temperature vacuum furnaces and presses. Use very simple equipment, therefore, the method of cooking is very cheap, respectively, reduces the price of the resulting powder with its high quality. Magnetic abrasive powder is composed mainly of magnetic powder component, abrasive powder component and a binder that binds the abrasive particles of the powder component and the magnetic powder of the component. How it is created contains the following steps: mixing the magnetic powder and the abrasive powder components to form uniform distribution of components in the mixture, feeding the mixture of the binder component, leaving the mixture for hardening at room temperature, and grinding the solidified mixture.

The disadvantages of the material produced in accordance with this patent is an increased coefficient of friction in the contact zone with the processed material, as well as the need to develop special polymer binder, as used as a cutting component diamond has low adhesive properties.

The problem to be solved is predlagaemym invention, is creating a new ferro-abrasive powder-tool with elevated polishing properties required for achieving high quality of the surfaces of the highly rigid materials: silicon, optical glasses, etc. and to improve the performance of blasting through improved cutting properties of the new composite ferro-abrasive powder.

The problem is solved in that in the composite powder consisting of a ferromagnetic base, an abrasive and a binder component, intended for use as an abrasive for polishing the highly rigid silicon and glass, is introduced as adhesive structural component of nanocrystalline aluminum hydroxide γ-lOO (boehmite). The size of the crystals of γ-AlOOH, obtained by industrial methods is usually 50-60 nm, a particle size of about 1 micron. In addition, due to nanocrystallinity and small particle size of γ-lOO homogeneous distributed over the volume, provides a high level of development and microporosity the surface of each grain of the entire composition, which greatly increases the adhesive properties of the composition containing the abrasive component. Due to the presence in the material powder tool of aluminum oxide having a lower coefficient of friction, the friction coefficient decreases whom is osili with the treated surface, decreasing the temperature in the cutting zone, which leads to increased health abrasive material [see Corundum refractories and ceramics. M, metallurgy, 1981, p.172]. Thus, modification of the properties of ferro-abrasive powder is due to the introduction in its composition of nanocrystalline aluminum hydroxide.

The essence of this invention lies in the fact that the proposed ferro-abrasive composite powder designed for use as an abrasive for polishing the highly rigid silicon and glass, consisting of a ferromagnetic component, which used iron powder, an abrasive component, which is used diamond powder and a binder component.

And ferro-abrasive composite powder contains additional adhesive structural component of nanocrystalline aluminum hydroxide γ-lOO, and the components are in the following volume ratio: 30 - 65% of the ferromagnetic component, up to 15% of the abrasive component (inclusive), 30-40% of the adhesion structure of the component and the rest of the binder component.

In addition, we offer ferro-abrasive composite powder, diamond powder is a powder of a synthetic diamond.

In addition, features of ferrous Isigny composite powder, where the binder is a polymer selected from the group of polystyrene, bakelite, high impact polystyrene, polycarbonate, resin plant resin, Novolac resin, cyanacrylate adhesive, and mixtures thereof.

The essence of the invention consists in that also features a method of manufacturing a ferro-abrasive composite powder containing the steps of mixing a ferromagnetic, abrasive and binder components.

And humidified ferromagnetic powder component is powdered iron mixed with dried at a temperature of 80-120°C. the nanocrystalline powder of aluminum hydroxide γ-lOO add abrasive powder component - diamond powder, a binder component, stir the mixture to obtain a homogeneous structure, subjecting the mixture to heating to a temperature of 290-350°C. dehydration of the composition, and form a ferro-abrasive composite powder with the desired grain size by wiping through the calibration screens.

In addition, it is proposed a method of manufacturing a ferro-abrasive composite powder, where applicable components have the following volume ratio: 30-65% of the ferromagnetic component, up to 15% of the abrasive component, 30-40% of the nanocrystalline powder of aluminum hydroxide γ-lOO and the rest of the binder component.

in Addition, features a method of manufacturing a ferro-abrasive composite powder, diamond powder using the powder of a synthetic diamond.

In addition, it is proposed a method of manufacturing a ferro-abrasive composite powder as a binder is used, the polymer is selected from the group of polystyrene, bakelite, high impact polystyrene, polycarbonate, Acrylonitrile-the best choice copolymer, Novolac resin, cyanacrylate adhesive, and mixtures thereof.

The proposed selection of the ratios of components in a volume ratio: 30-65% - ferromagnetic component, up to 15% of the abrasive component, 30-40% of the nanocrystalline powder of aluminum hydroxide - γ-lOO and the rest of the binder component is explained by the following:

- the content of aluminum hydroxide γ-lOO below 30% degrades the polishing properties of the composite;

- the excess amount of aluminum hydroxide γ-lOO over 40% leads to delamination of the composite;

- introduction of diamond powder over 15% leads to an increase in material cost as a whole;

- the content of the binder component in the composition is below 5% does not ensure wetting of all grains and conglomerates of the composition, and the excess binder content above 15% leads to decrease in strength.

The technical result achieved by the invention is to improve the quality of the and the workpiece, provide opportunities for abrasive machining at higher cutting speeds and feeds by introducing as a component of ferro-abrasive powder of nanocrystalline aluminum hydroxide γ-lOO, reduces the coefficient of friction with the material to be processed by ultradispersed and own lower coefficient of friction. In addition, there are additional technical effects: the decrease of temperature in the working area, lower cutting forces, the homogeneity of the composition and properties by volume of the abrasive tool.

An example of carrying out the invention

Hydrated powder of ferromagnetic bases mixed with dried at a temperature of 80-120°C. a powder of aluminum hydroxide γ-lOO that under stirring sticks to each Poroshenko basis. Next to these components add diamond and polymer powders and by mixing form a composite ferro-abrasive powder. Then blend for hydration is subjected to heating to a temperature of 290-350°C and then, after cooling, the resulting composition is rubbed for grinding rubbing machine PS-1 with a calibrated sieves 0,63 mm

Abrasive capacity of the powders on the basis of aluminum oxide and solid solutions was determined according to GOST 2912-79 (p) on the polishing machine-15 with the faceplate of bitumen grade No. 5. The polished sample was soboyejo of steel WA, tempered to a hardness of HRC 58-60. The polishing slurry was prepared from 50 g of the analyzed powder and 150 ml of distilled water. The abrasive performance of the powder was calculated by the mass loss of the formula:

,

where Δ - weight change of the sample during polishing;

S is the surface area of the sample, mm2;

τ is the time of polishing.

Determination of roughness Rzthe surface after polishing was performed using the microinterferometer MIM-4 according to GOST 5425-70 on the base length of 0.08 mm

The table shows the intensity values of material removal by polishing of the samples in a magnetic field of single crystal silicon and optical glass K8 according to the method described in [see Khomich NS, Alekseev YG, Miss B.C. and other "Nanotechnology polishing in the magnetic field of the surfaces of the parts of optics, electronics and laser technology: Powder metallurgy: achievement and challenges. // Sat. reports international. Scientific and technical. conference, Mn.: BNTU, 2005, - p.223-225], according to which the surface is polished with powder-tools, the particles are pressed to the workpiece by the magnetic field. Polishing occurs when moving powder and the surface of the parts relative to each other at the time of polishing 30 minutes

In this series of tests as a binder was applied powder bakelite, is received from novaliches phenol-formaldehyde oligomer.

The test results ferro-abrasive composite powder
№ p/pThe composition of the composite powder,% vol.The intensity of the material removal rate, µm/minThe surface roughness, Rz, mm
glass K8siliconglass K8silicon
1.The prototype AP (45) + OP (40) + P (15)0,10,09>50>50
2.AL (15) + OP (45) + HA (30) + P (10)0,120,1450,10,1
3.AP (10) + OP (40) + HA (40) + P (10)0,150,140,10,08
4.AP (10) + OP (45) + HA (40) + P (15)0,13 0,140,10,07
5.AP (5) + OP (45) + HA (40) + P (10)0,110,130,120,12

In the table we have adopted the following legend: AP - diamond powder, OP - ferroportin, HA - aluminum hydroxide, N - polymer, Rz - nano roughness of the sample.

The analysis of the table shows that the use of magnetic-abrasive machining of the proposed composite powders tools containing iron powder, a powder of aluminum hydroxide γ-lOO, diamond powder, a polymer binder provides compared with the composition of prototype formation significantly better nano with roughness up to 0.12 microns (120 nm) and high intensity material removal rate up to 1.5 times. These figures correspond to modern requirements and prospects of development of mass production of electronic and optical industry.

1. Ferro-abrasive composite powder for polishing the highly rigid silicon and glass, consisting of a ferromagnetic component, the abrasive component and a binder, characterized in that it further comprises a structural adhesive component - nano is ristalliceski aluminum hydroxide γ-lOO, as the ferromagnetic component it contains iron powder, and as an abrasive component - diamond powder, and these components are located in the following volume ratio:

ferromagnetic component30-65%
adhesive structural component30-40%
abrasive componentup to 15%
a binder componentrest

2. Ferro-abrasive composite powder according to claim 1, characterized in that the quality of the diamond powder used is a powder of a synthetic diamond.

3. Ferro-abrasive composite powder according to claim 1, characterized in that the binder component is a polymer selected from the group of polystyrene, high impact polystyrene, polycarbonate, Acrylonitrile-the best choice copolymer, Novolac resin, cyanacrylate adhesive, and mixtures thereof.

4. A method of manufacturing a ferro-abrasive composite powder containing the steps of mixing a ferromagnetic, abrasive and a binder component, wherein the hydrated ferromagnetic powder component, as cataloguesales iron powder, mixed with dried at a temperature of 80-120°C. the nanocrystalline powder of aluminum hydroxide γ-lOO add abrasive powder component is a diamond powder and a binder component, stir the mixture to obtain a homogeneous structure, is subjected to heating to a temperature of 290-350°C. dehydration of the composition and form a ferro-abrasive composite powder with the desired grain size by wiping through the appropriate calibration sieve.

5. A method of manufacturing a ferro-abrasive composite powder according to claim 4, characterized in that the components used have the following volume ratio:

ferromagnetic component30-65%
the nanocrystalline powder of aluminum hydroxide γ-lOO30-40%
abrasive componentup to 15%
a binder componentrest

6. The method according to claims 4 and 5, characterized in that the quality of the diamond powder using the powder of a synthetic diamond.

7. The method according to claims 4 and 5, characterized in that the binder component is used, the polymer is selected from the group of polystyrene, shock-resistant is polystyrene, polycarbonate, Acrylonitrile-the best choice copolymer, Novolac resin, cyanacrylate adhesive, and mixtures thereof.



 

Same patents:

FIELD: railway transport.

SUBSTANCE: said utility invention relates to the railway transport, in particular to friction modifiers applied on railway stock wheel treads. Character: the friction and adhesion activator is foam glass.

EFFECT: increase in traction force in difficult track rolling stock operating conditions.

1 tbl

FIELD: technological processes, chemistry.

SUBSTANCE: group of inventions is related to abrasive and/or chemically active particles and their application in polishing and planarisation. Abrasive composition for polishing of substrates contains multiple abrasive particles that contain distribution of polydisperse particles size, at that median size of particles by volume makes from approximately 20 nanometre to approximately 100 nanometre, value of difference, in volume, is equal or more than approximately 15 nanometre, where fraction of specified particles, larger than approximately 100 nanometres makes less than or equal to approximately 20 volume % of abrasive particles. Suspension abrasive composition is also presented for polishing of substrates, as well as method for polishing of substrates by abrasive composition.

EFFECT: high rate of polishing is achieved, as well as increased smoothness of polished surface, proper planarisation and low densities of defects.

19 cl, 4 ex, 4 tbl, 2 dwg

FIELD: construction.

SUBSTANCE: polishing suspension includes fluid medium and abrasive material in the form of particles, including soft abrasive particles, hard abrasive particles and colloid particles of silicon dioxide. Hardness of soft abrasive particles in Mohs scale is not more than 8, hardness of hard abrasive particles in Mohs scale is not less than 8, weight ration soft to hard abrasive particles is not less than 2:1, and suspension is partially flocculated and includes agglomerates with soft abrasive particles, hard abrasive particles and colloid particles of silicon dioxide. Also invention claims method of ceramic part polishing using claimed suspension.

EFFECT: high speed and enhanced quality of polishing.

17 cl, 1 tbl, 4 dwg

FIELD: chemistry.

SUBSTANCE: mix includes abrasive filler and iron powder in % ratio of 75-85:15-25. Abrasive filler is produced of a mix of iron powder with non-ferromagnetic hard-alloy metals or their carbides or borides melted in graphite crucible. Hard-alloy metal is processed to reach 1100-1200 kg/mm2 hardness and obtain ferromagnetic properties, ground to 0.2-0.32 mm particle size and mixed with iron powder.

EFFECT: improved durability and wearing capacity of imitated soil.

4 cl

FIELD: material for increase of friction coefficient of vehicle wheels.

SUBSTANCE: material is described for provision of vehicle movement start on slippery snow or ice surface, which consists of disperse loose material composition in the form of wooden chips with size from 1 mm to 10 mm and antiseptic - boric acid that is contained in the material in amount from 1 to 2 % weight.

EFFECT: increase of friction coefficient between vehicle wheel and iced surface.

2 tbl, 1 ex

FIELD: abrasives.

SUBSTANCE: invention relates to alumina-based abrasive flour grains used in polishing, grinding, and finishing of surfaces of high-precision metal, glass, and stone objects. Manufacturing method according to invention comprises mixing aluminum hydroxide with inoculating crystals followed by heat-steam treatment at pressure 30 to 400 atm and temperature 340-450°C. Together of inoculating crystals, corundum crystal growth passivation agent is added to aluminum hydroxide in the form of oxide compounds of phosphorus or silicon in quantity from 0.001 to 0.1% (converted to phosphorus oxide or silicon oxide) based on the weight of alumina. As inoculating crystals, fine-crystalline α-ferric oxide or ferric oxy-hydroxides are used in quantities 0.005 to 0.3% on the weight of alumina and, as oxide compounds of phosphorus or silicon passivating corundum crystal growth, phosphoric acid, sodium polyphosphates, sodium or potassium silicates are used.

EFFECT: enabled preparation of monodisperse product having narrow crystal size distribution.

1 tbl, 7 ex

FIELD: binders used for making abrasive parts and tools.

SUBSTANCE: binder is formed during process of treating hydrocarbon gas in pyrolysis condition inside pores of blank of abrasive product. Binder contains, mass%: technical carbon, 0.01 - 3 %; pyrocarbon or pyrocarbon with fibrous carbon, the balance. Hydrocarbon gas may contain in addition 0.15 vol% of acetylene.

EFFECT: possibility for using abrasive product with such binder for highly effective cutting of hard alloy without dressing of tool.

3 cl, 1 tbl, 3 ex

FIELD: abrasive treatment; production abrasive particles and articles from them.

SUBSTANCE: abrasive particles contain glass ceramic including Al2O3 and oxide of metal different from Al2O3. Part of Al2O3 is present in glass ceramic in form of alpha Al2O3. Specification gives description of methods of production of abrasive particles and grinding by means of abrasive articles containing binder and said abrasive particles.

EFFECT: improved working characteristics of abrasive particles and articles made from them; low cost of production.

10 cl, 12 dwg, 3 tbl, 36 ex

FIELD: chemical industry; methods of production the nanoporous ultra-fine powders and sol-gel made out of alpha aluminum oxide.

SUBSTANCE: the invention is pertaining to creation of the nanoparticles from alpha aluminum oxide, to the method of their preparation and to the method of their polishing. The powder from alpha aluminum oxide contains the particles from alpha aluminum oxide, at that about 99 % of these particles have the dimension roughly from 10 up to 100 nanometers, at that about 99 % of the particles have the distribution with the average dimension about 10 nanometers. The method of production of the particles from alpha aluminum oxide having the dimension roughly from 10 up to 100 nanometers includes the following operations: usage of the gel, which contains at least one precursor of the aluminum oxide and the flock of inoculation particles from alpha aluminum oxide, at that the inoculation particles from alpha aluminum oxide have the average dimension roughly less than 100 nanometers; drying of the gel and kilning of the dry gel at the temperature of roughly from 750°С up to 950°С allowing to originate formation of the alpha aluminum oxide without grow body of the particles sizes to receive the particles from alpha aluminum oxide, having the average dimension roughly less than 100 nanometers and distribution with the average dimension about 10 nanometers. The produced powder is used in the form of the suspension use in the method of polishing of the base by the suspension application on the separation surface between the base and the polishing tool. The invention allows to produce the fine powders of the alpha aluminum oxide, which may be used in the polishing process.

EFFECT: the invention ensures production of the fine powders of the alpha aluminum oxide, which may be used in the polishing process.

32 cl, 2 dwg, 4 ex

FIELD: production of nano-porous powders from alpha aluminum oxide used for polishing.

SUBSTANCE: proposed nano-porous powder contains primary particles of alpha aluminum oxide at average diameter lesser than 10 nm and inter-permeable net of pores or voids. Proposed powder is prepared by method including the following operations: use of inorganic sol containing at least one precursor of aluminum oxide and many seeding particles of alpha aluminum oxide; addition of at least one water-soluble organic polymer to inorganic sol for obtaining organic-inorganic sol; sublimation drying of organic-inorganic sol for obtaining solid gel and firing of solid gel. Nano-porous powder is made at additional grinding of powder from alpha aluminum oxide after firing. Suspension containing the powder of nano-size is used for polishing the base by applying the suspension on interface between base and polisher.

EFFECT: high purity of fine homogeneous powders.

71 cl, 3 dwg, 2 ex

FIELD: abrasives.

SUBSTANCE: invention relates to alumina-based abrasive flour grains used in polishing, grinding, and finishing of surfaces of high-precision metal, glass, and stone objects. Manufacturing method according to invention comprises mixing aluminum hydroxide with inoculating crystals followed by heat-steam treatment at pressure 30 to 400 atm and temperature 340-450°C. Together of inoculating crystals, corundum crystal growth passivation agent is added to aluminum hydroxide in the form of oxide compounds of phosphorus or silicon in quantity from 0.001 to 0.1% (converted to phosphorus oxide or silicon oxide) based on the weight of alumina. As inoculating crystals, fine-crystalline α-ferric oxide or ferric oxy-hydroxides are used in quantities 0.005 to 0.3% on the weight of alumina and, as oxide compounds of phosphorus or silicon passivating corundum crystal growth, phosphoric acid, sodium polyphosphates, sodium or potassium silicates are used.

EFFECT: enabled preparation of monodisperse product having narrow crystal size distribution.

1 tbl, 7 ex

The invention relates to abrasive industry, namely, to obtain the normal oxide fusible raw bauxite charge

The invention relates to a method for producing abrasive particles chattnooga deposition of the refractory material particles centers on the basis of aluminum oxide, abrasive particles obtained in this way, and to abrasive products made using such particles

The invention relates to the manufacture of abrasive powders used in tools for metal surface treatment, in particular the production of grinding powders based-modification of aluminum oxide (corundum)

FIELD: abrasives.

SUBSTANCE: invention relates to alumina-based abrasive flour grains used in polishing, grinding, and finishing of surfaces of high-precision metal, glass, and stone objects. Manufacturing method according to invention comprises mixing aluminum hydroxide with inoculating crystals followed by heat-steam treatment at pressure 30 to 400 atm and temperature 340-450°C. Together of inoculating crystals, corundum crystal growth passivation agent is added to aluminum hydroxide in the form of oxide compounds of phosphorus or silicon in quantity from 0.001 to 0.1% (converted to phosphorus oxide or silicon oxide) based on the weight of alumina. As inoculating crystals, fine-crystalline α-ferric oxide or ferric oxy-hydroxides are used in quantities 0.005 to 0.3% on the weight of alumina and, as oxide compounds of phosphorus or silicon passivating corundum crystal growth, phosphoric acid, sodium polyphosphates, sodium or potassium silicates are used.

EFFECT: enabled preparation of monodisperse product having narrow crystal size distribution.

1 tbl, 7 ex

FIELD: chemistry.

SUBSTANCE: making of compositional ferroabrasive powder includes mixing of the wet ferromagnetic powder component (iron powder) with dried at temperature 80-120°C adhesive structure-forming component - powder of nanocrystall aluminium hydroxide γ-AlOOH. Then abrasive powder component (diamond powder) and binding component are added. The mixture is agitated up to obtaining of homogenous structure and heated up to temperature of composition dehydratation - 290-350°C. Ferroabarsive compositional powder with desired particle size is formed by its rubbing through corresponding calibrated sieves. Ferroabrasive composite powder components have the following volume ratio: ferromagnetic component - 30-65%, adhesive -forming component - 30-40%, abrasive component up to 15%, binding component - the rest.

EFFECT: quality improvement of processed surfaces alongside with increase of material removal intensity, increase of abrasive processing speed, decrease of the working zone temperature.

7 cl, 1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: when making abrasive tools, several super-hard sub-micrometre or nanosized diamond particles or cubic boron nitride or combination of these materials and having vitreophilic surfaces which can form chemical bonds with oxides are used. A coating of oxide precursor material is deposited on the particles and thermal treatment is then carried in order to dry and clean the coating. The coatings are selected from a group comprising nitrides of titanium, vanadium, niobium, tantalum, molybdenum and tungsten or carbides of vanadium, niobium, tantalum, molybdenum and tungsten, an anatase phase of titanium dioxide, a rutile phase of titanium dioxide, tetragonal zirconium dioxide, monoclinic zirconium dioxide, zirconium dioxide, stabilised with yttrium oxide or magnesium oxide, transition structures or an alpha-phase of aluminium oxide or oxides of vanadium, niobium, tantalum, hafnium, molybdenum and tungsten, quartz glass.

EFFECT: invention enables coating of sub-micrometre or nanosized abrasives.

35 cl, 6 dwg, 2 tbl, 15 ex

FIELD: process engineering.

SUBSTANCE: invention relates to processing by abrasives and may be used for production of composite material machining tools. Abrasive article has abrasive body including abrasive grains made of microcrystalline aluminium oxide and contained in glass-like binder. The latter features abrasive grain dissolution factor not exceeding about 1.5 wt %.

EFFECT: integrity of abrasive grains in abrasive article, better quality of grinding.

27 cl, 3 dwg, 2 ex, 2 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to grinding and may be used for production of abrasive tools, for example, grinding wheels. Abrasive article comprises abrasive body with abrasive grains in binder. Abrasive body comprises the region of passivation including spinel material that covers at least 60% of abrasive grains. Note here that said spinel material can be arranged at interface between abrasive grains and binder matrix.

EFFECT: decreased dissolution and destruction of abrasive grains in forming of abrasive article.

23 cl, 7 dwg, 4 tbl, 3 ex

FIELD: process engineering.

SUBSTANCE: invention can be used for production of abrasive materials. In compliance with this invention, abrasive particles represent shaped abrasive particles with inclined sidewall. Every shaped abrasive particle contains aluminium alpha-oxide and gas first and second faces separated by thickness t. Said shaped abrasive particles feature forming slope angle α between second face and inclined sidewall making 95-130 degrees or inclined sidewall with radius R between first and second faces. Radius R makes 0.5-2 if thickness t. Abrasive material with coating comprises bottom adhesive layer on the substrate first smooth surface, shaped abrasive particles making the abrasive layer and top adhesive layer. Most shaped abrasive particles are secured to bottom adhesive layer by inclined sidewall and feature orientation angle β equal to 50-85 degrees. Abrasive layer consists of shaped abrasive particles by at least 5% by weight.

EFFECT: higher efficiency of cutting.

21 cl, 11 dwg, 1 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to abrasive articles. An abrasive article comprises an abrasive body on a binder, having abrasive particles which contain microcrystalline aluminium oxide (MCA) enclosed in a binding material. The strength factor of the abrasive body on the binder (MOR/MOE) is equal to at least about 0.80, where MOR is the modulus of rapture and MOE is the modulus of elasticity.

EFFECT: improved performance of abrasive articles on the binder.

15 cl, 11 dwg, 4 tbl, 5 ex

Up!