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Magnetic liquid and the manufacturing process

Abstract: a brief introduction of the magnetic fluid type,[link widoczny dla zalogowanych], nature, crafts and in the current main application. Key words: magnetic fluid; applications; manufacturing; ultrasonic Character and Applications of Magnets Liquids Abstract: In this paper, the applications and characteristic of magnets liquid is also given. Keywords: magnets liquids; applications; manufacture; ultrasonic wave 1 Introduction magnetic fluids was first in 1965, NASA spacesuit helmet to solve the technical problems of the rotating seal first developed successful. Spacesuits worn by astronauts into space as a key part - the neck, must be made with liquid magnetic material. Aerospace cap and the neck is the connection between the suit, only to let the astronauts to free rotation of the head, but also sealed high. If the seal is not enough, the oxygen leak in the suit, astronaut life-threatening. The joints, if the solid material is clearly too hard, and the average density of matter is not enough liquid, only liquid nano-magnetic materials to meet the requirements. The so-called magnetic fluid (Magnetic Liquids), not refer to the magnetic liquid (substance in the liquid, the temperature is higher than the Curie temperature, so there is no liquid magnetic material), but the surfactant treatment through the nano-scale ultra-fine magnetic particles dispersed in the base fluid in the formation of a homogeneous colloidal solution. The solution under the action of gravity and magnetic field does not appear the phenomenon of condensation and precipitation, with a magnetic solid and liquid flow, so it has many unique properties, in electronics, instrumentation, machinery, chemical, environmental, medical and other industries are has a unique and widely used. According to different purposes, you can choose different base fluid products. 2 classification magnetic fluid magnetic liquid by materials, the production of ultrafine particles, dispersed in different methods, divided into the following categories: (1) ferrite-based magnetic fluids mainly metal oxide were used as magnetic particles, water, hydrocarbons, mineral oil, refined oil, ester-based fluid, turbine oil, oil-based liquid isoflurane. (2) metal-based magnetic fluid as the particles of metal or alloy, according to the base were divided into non-conductive liquid type and conductor type. Non-conductive metal magnetic fluid generally toluene or kerosene-based liquid, conductor type were on non-magnetic metal film (or alloy film) to cover the magnetic metal particles. (3) composite magnetic fluid magnetic liquid and he is an ordinary non-magnetic particles to form a new type of composite magnetic fluids. 3 the magnetic properties of liquids has both magnetic and magnetic fluid flow, so it has many unique magnetism, fluid mechanics, optical and acoustic properties. Magnetic fluid showed superparamagnetic, intrinsic coercive force is 0, no residual magnetism; external magnetic field, the magnetic fluid is magnetized to meet the modified Bernoulli equation. Compared with the conventional Bernoulli equation, adding a magnetic, magnetic fluids with other fluids that do not have, and magnetic properties associated with the new: for example, the apparent density of magnetic fluid with magnetic field intensity increases . When the light through the dilution of the magnetic fluid, it will produce birefringence effect of light color with two-way phenomenon. When the magnetic fluid is magnetized, the Shixiang for anisotropic magnetic field with light,[link widoczny dla zalogowanych], polarized light electric vector parallel to the external magnetic field direction than perpendicular to the direction of the external magnetic field to absorb more, with a higher refractive index. For the magnetic field, showing anisotropy; magnetic fluids in an alternating field with the magnetic permeability dispersion, magnetic viscosity and so on. 4 magnetic fluid production methods (1) the basic conditions for access to magnetic fluid the particle size ① should be less than some critical size, the critical size of 10 nm or less. ② particles in a solvent should meet the requirements of some of the surface activity, which even in the van der Waals energy under the action of other, not in the condensate. (2) production process of magnetic fluid with magnetic oxide ultrafine particles of the production process as an example of magnetic oxides stable, easily made into powder, widely used. Oxide particle with magnetic fluid to be distributed in the vast majority of 10 nm or less. General ferrite is magnetite as the main oxides, from aqueous solutions of metal salts by coprecipitation into nano-ultrafine particles. Magnetite (Fe2O3 · 2Fe3O4), for example, is in the Fe2 + and Fe3 + concentration ratio of 1:2 iron salt solution by adding alkali solution, such as NaOH, to precipitate Fe2O3 · 2Fe3O4. In the reaction process, by adjusting the solution temperature, iron salt, alkali and in excess, reaction time, particle size can be controlled. Addition, the following methods are available to oxide ultrafine particles: ① reaction of the ferrite solid surface active agent in the presence of oil in the long ball. ② the ferrite composition metal alkoxides, and put him in a solvent soluble in ethanol, hydrolysis obtained. ③ use of plasma, arc, etc. to metal evaporation,[link widoczny dla zalogowanych], amount of oxygen in the rarefied gas containing condensed liquid to obtain 5 Application of magnetic (1) magnetic fluids were previously called Magnetic Liquid is the most widely used magnetic seal technology, especially in the required vacuum, dust, or seal gas dynamic seal in the special environment the most applicable. In the high-fidelity speakers,[link widoczny dla zalogowanych], the motor damping, magnetic sensors, magnetic fluids are unique aspects of the application. Magnetic fluid shaft seal principle of magnetic fluid dynamic seal is a non-contact seals (ie, moving parts and static parts is no direct contact), and its working principle is: the ring magnet, magnetic boots and magnetic shaft guide constitute a closed magnetic circuit, the use of permanent magnets in the magnetic energy, in the shaft and the pole shoe gap pole tooth profile generated in the top of the strength of white non-uniform magnetic field, the magnetic fluid sucked tightly to form a magnetic fluid ring, the gap closed, so as to achieve the purpose of sealing. Figure 1 and Figure 2. Features: ① no wear, because the nature of magnetic fluid with a liquid, and because the base fluid is lubricating, it can also act as a lubricant. ② seal is good, can be used to vacuum up to 10 ~ 5 Pa. ③ no leakage. (2) magnetic fluid vacuum seal connector is a 2 can provide a relatively closed space between reliable rotation connection device. Full range is designed to be widely used on many occasions, such as silicon furnace, all kinds of coating equipment, vapor deposition,[link widoczny dla zalogowanych], liquid regeneration, semiconductor etching systems, ultra-high vacuum systems and equipment. Figure 3. Magnetic fluid vacuum seal connector assembly of vacuum devices under various types of commonly used vacuum rotation axis parameters of design and manufacture of connector technology can directly substitute the appropriate use of the vacuum sealed connector, the basic need to transform the original equipment.