WO1997032321A1 - Magnetofluid mit hoher sättigungsmagnetisierung - Google Patents
Magnetofluid mit hoher sättigungsmagnetisierung Download PDFInfo
- Publication number
- WO1997032321A1 WO1997032321A1 PCT/DE1997/000443 DE9700443W WO9732321A1 WO 1997032321 A1 WO1997032321 A1 WO 1997032321A1 DE 9700443 W DE9700443 W DE 9700443W WO 9732321 A1 WO9732321 A1 WO 9732321A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- particles
- volume
- magnetofluid
- viscosity
- modified
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
- H01F1/44—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of magnetic liquids, e.g. ferrofluids
- H01F1/442—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of magnetic liquids, e.g. ferrofluids the magnetic component being a metal or alloy, e.g. Fe
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
- A61M60/00—Blood pumps; Devices for mechanical circulatory actuation; Balloon pumps for circulatory assistance
- A61M60/90—Details not provided for in groups A61M60/40, A61M60/50 or A61M60/80
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K1/00—Details of the magnetic circuit
- H02K1/02—Details of the magnetic circuit characterised by the magnetic material
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K33/00—Motors with reciprocating, oscillating or vibrating magnet, armature or coil system
- H02K33/02—Motors with reciprocating, oscillating or vibrating magnet, armature or coil system with armatures moved one way by energisation of a single coil system and returned by mechanical force, e.g. by springs
Definitions
- Magnetic liquids are so-called “smart” materials which, in interaction with strong external magnetic fields or magnetic field gradients, are both fixed locally and can even be brought into predetermined positions, even against gravity. Their colloidal stability is maintained and they behave like a continuous liquid phase. The term magnetic fluid was usually coined for this.
- the decisive factor for their quality is the value of the saturation magnetization, because this is proportional to the specific interaction force of the magnetic fluid with the external magnetic field.
- the magnetofluids are used in blood pumps, for producing magnetofluid sensors with high sensitivity or for magnetofluid seals with a higher sealing performance.
- such magnetic fluids are stable dispersions with superparamagnetic properties and are composed of ferromagnetic or ferromagnetic nanometer particles, surface-active substances and a carrier liquid.
- the surface-active substances bring about dispersion and coloidal stabilization of the particles in the carrier liquids.
- carrier liquids are used as carrier liquids, such as water, hydrocarbons, perfluorocarbon ethers, diesters and silicone oils.
- Magnetite which is modified with special surface-active substances, such as medium-chain organic acids, is used as the magnetic component
- Magnetofluids with saturation magnetizations of 10 to 40 mT (Ferrofluidics Corporation) and up to 90 mT are commercially available
- Magnetic liquids which contain metallic nanometer particles instead of magnetite particles.
- Typical ferromagnetic metals are iron, cobalt and nickel, the particles of which are produced by thermolysis of their carbonyls or by aerosol formation.
- Polymers such as polybutadiene derivatives with a molecular weight of at least 1000 or polybutenylsuccin polyamm and surfactants such as oil-soluble alkylsulfonates or sarkosyl-O and Duomeen-TDO are described as stabilizers.
- surfactants such as oil-soluble alkylsulfonates or sarkosyl-O and Duomeen-TDO are described as stabilizers.
- the value of the saturation magnetization is far below 30 mT, mostly only at 5 mT. This means that even small forces can also be transmitted regularly.
- the surfactant concentrations in the solvent are so low that the critical micelle formation concentration for the inverse micelles is not reached.
- the object of the invention is therefore to create a magnetic fluid which has a saturation concentration which is above 100 mT in order to be able to transmit higher forces. According to the invention, this is done by stably dispersing cobalt and nanometer particles modified with monomolecular adsorption layers in carrier liquids, the volume concentration of the ferromagnetic component being 5 to 35 percent, primarily 15 to 30%, and the volume concentration of the modified particles (naked particles with Adsorption shell) is up to 50 volume percent.
- the saturation magnetization Due to the high volume concentration of the ferromagnetic components and the value for the saturation magnetization of the naked particles, which are 5 to 20 nm in size, that is a factor of 3 to 4 times higher than magnetite, the saturation magnetization has a value between 100 and 400 mT , but primarily between 150 and 300 mT.
- the modified particles are produced by the known chemical processes via nucleation / crystal growth processes, namely the thermolysis of their carbonyls directly in an organic solvent in the presence of polymers or surfactants.
- polymers or surfactants with reactive nitrogen compounds are used which are well above the critical inverse micelle formation concentration.
- polymers or surfactants with reactive sulfo or nitrogen compounds are used for stabilizing the cobalt particles.
- the reactive groups are adsorbed on the surface of the metallic particles to form monomolecular layers.
- the strong adsorption The ability and firm binding of the surfactants means that they have an antioxidant effect on the ferromagnetic particles.
- ferromagnetic particles To produce a magnetic liquid with high saturation magnetization, ferromagnetic particles must meet the following requirements: use of ferromagnetic particles, such as iron and cobalt, which have a 3 to 4 times higher saturation magnetization than magnetite particles; Use of iron and cobalt particles in particle sizes up to 20 nm, taking into account the guarantee of sufficient colloidal particle stability; Use of polymers and / or surfactants which adsorb monomolecularly with layer thicknesses of 1.2 to 2 nm, taking into account the guarantee of sufficient colloidal particle stability.
- ferromagnetic particles such as iron and cobalt, which have a 3 to 4 times higher saturation magnetization than magnetite particles
- Use of iron and cobalt particles in particle sizes up to 20 nm taking into account the guarantee of sufficient colloidal particle stability
- Use of polymers and / or surfactants which adsorb monomolecularly with layer thicknesses of 1.2 to 2 nm, taking into account the guarantee of sufficient colloidal particle stability.
- ferromagnetic iron or cobalt particles which are coated with monomolecular adsorption layers can still be dispersed colloidally stably in carrier liquids if the ratio of the radii of the naked to the modified particles is 1.10 to 1.30, preferably 1.15 to 1.20 .
- a solids content of the ferromagnetic component of 5 to 35 vol% is thereby achieved, which in turn increases the saturation magnetization up to 400 mT.
- the magnetofluid should remain fluid even with a high particle concentration. This is achieved that the viscosity of the carrier liquid at room temperature is between 0.7 and 10 mPas, mainly between 1 and 5 mPas, and that only the necessary amount of polymer and / or surfactant is dissolved in the carrier liquid.
- the cobalt and iron nanometer particles are produced by modifying the chemical methods described in accordance with the prior art by thermolysing their carbonyls in organic carrier liquids.
- the particle size of the bare metal core can be changed in a controlled manner by carrying out the reaction (temperature), by the chemical composition and concentration of the reactants, in particular by the chemical composition of the solvent
- the mixture is placed in a three-necked flask with a stirrer, cooler and gas inlet tube and heated at 120 ° C under pure argon until the formation of carbon monoxide has ended.
- the co-magnetic fluid formed has an Ms value of 30 mT.
- Your magnetization curve has none Hysteresis, the viscosity is only 4 mPas.
- the half-life of the oxidation is several months. By evaporation of the solvent, the Ms value was increased to 250 mT
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP97918008A EP0823123A1 (de) | 1996-02-27 | 1997-02-27 | Magnetofluid mit hoher sättigungsmagnetisierung |
JP53051997A JP3187844B2 (ja) | 1996-02-27 | 1997-02-27 | 高飽和磁化の磁性流体 |
CA002219503A CA2219503C (en) | 1996-02-27 | 1997-02-27 | Magnetofluid with high saturation magnetisation |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19609281A DE19609281C1 (de) | 1996-02-27 | 1996-02-27 | Magnetofluidunterstützter elektromagnetischer Antrieb für eine Blutpumpe zur Unterstützung oder zum teilweisen bis totalen Ersatz des Herzens |
DE19609281.7 | 1996-02-27 | ||
DE19654864A DE19654864A1 (de) | 1996-02-27 | 1996-02-27 | Magnetofluid mit einer Sättigungsmagnetisierung von 150 bis 450 mT |
DE19654864.0 | 1997-02-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997032321A1 true WO1997032321A1 (de) | 1997-09-04 |
Family
ID=26023644
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/DE1997/000443 WO1997032321A1 (de) | 1996-02-27 | 1997-02-27 | Magnetofluid mit hoher sättigungsmagnetisierung |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0823123A1 (de) |
CA (1) | CA2219503C (de) |
WO (1) | WO1997032321A1 (de) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20230170764A1 (en) * | 2021-11-30 | 2023-06-01 | Hyundai Motor Company | End coil cooling structure for an induction motor |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3284358A (en) * | 1963-06-10 | 1966-11-08 | Chevron Res | Process for improving the magnetic properties of colloidal dispersion of magnetic particles |
JPS6043803A (ja) * | 1983-08-19 | 1985-03-08 | Pioneer Electronic Corp | 磁性流体 |
JPS6293911A (ja) * | 1985-10-21 | 1987-04-30 | Natl Res Inst For Metals | 磁性流体の製造装置 |
JPS6293910A (ja) * | 1985-10-21 | 1987-04-30 | Natl Res Inst For Metals | 磁性流体の製造方法 |
JPH01254243A (ja) * | 1988-04-02 | 1989-10-11 | Cosmo Oil Co Ltd | 磁性流体の製造方法 |
-
1997
- 1997-02-27 WO PCT/DE1997/000443 patent/WO1997032321A1/de not_active Application Discontinuation
- 1997-02-27 CA CA002219503A patent/CA2219503C/en not_active Expired - Fee Related
- 1997-02-27 EP EP97918008A patent/EP0823123A1/de not_active Withdrawn
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3284358A (en) * | 1963-06-10 | 1966-11-08 | Chevron Res | Process for improving the magnetic properties of colloidal dispersion of magnetic particles |
JPS6043803A (ja) * | 1983-08-19 | 1985-03-08 | Pioneer Electronic Corp | 磁性流体 |
JPS6293911A (ja) * | 1985-10-21 | 1987-04-30 | Natl Res Inst For Metals | 磁性流体の製造装置 |
JPS6293910A (ja) * | 1985-10-21 | 1987-04-30 | Natl Res Inst For Metals | 磁性流体の製造方法 |
JPH01254243A (ja) * | 1988-04-02 | 1989-10-11 | Cosmo Oil Co Ltd | 磁性流体の製造方法 |
Non-Patent Citations (5)
Title |
---|
J.POPPLEWELL ET AL: "Ferromagnetic liquids-their magnetic properties and applications", IEEE TRANSACTIONS ON MAGNETICS, vol. 17, no. 6, November 1981 (1981-11-01), NEW YORK US, pages 2923 - 2928, XP002033937 * |
LAMBRICK D B ET AL: "THE PREPARATION OF CO/FE ALLOY FINE PARTICLES FROM HFECO3(CO)12", IEEE TRANSACTIONS ON MAGNETICS, vol. 24, no. 2, 1 March 1988 (1988-03-01), pages 1644 - 1646, XP000174167 * |
PATENT ABSTRACTS OF JAPAN vol. 009, no. 169 (E - 328) 13 July 1985 (1985-07-13) * |
PATENT ABSTRACTS OF JAPAN vol. 011, no. 294 (E - 544) 22 September 1987 (1987-09-22) * |
PATENT ABSTRACTS OF JAPAN vol. 014, no. 007 (C - 673) 10 January 1989 (1989-01-10) * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20230170764A1 (en) * | 2021-11-30 | 2023-06-01 | Hyundai Motor Company | End coil cooling structure for an induction motor |
US11848598B2 (en) * | 2021-11-30 | 2023-12-19 | Hyundai Motor Company | End coil cooling structure for an induction motor |
Also Published As
Publication number | Publication date |
---|---|
CA2219503A1 (en) | 1997-09-04 |
EP0823123A1 (de) | 1998-02-11 |
CA2219503C (en) | 2001-04-24 |
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