Study on Preparation and Property of FeSiAl Magnetic Powder Cores
|Keywords||FeSiAl powder cores Permeability Loss Eddy current loss|
The metal powder cores is a soft magnetic material manufactured by powder metallurgy process the special magnetic enables obtaining difficult to compare the advantages of other materials in many applications. In the 21st century, the progress of science and technology requires a variety of high-performance electronic devices, which put forward higher requirements for powder cores. FeSiAl powder cores because of its high resistance, high-frequency loss and low, low prices, is widely used in high-frequency do inductor core. Preparation process of FeSiAl powder cores passivation, insulation coating, pressure forming, heat treatment process factors on the magnetic properties and mechanical properties of FeSiAl powder cores. The insulation technology is a key technology for powder cores prepared. First, without adding mica, investigated the influence of the binder type on the properties of the magnetic powder core, preliminary exploration binder; secondly, on the basis of the insulating program, add a small amount of mica Investigation of the binder content of the sample magnetic and mechanical properties; Finally, determine the the mica insulating agent investigated the impact of the of mica added amount of the magnetic properties of the magnetic powder core samples to determine the appropriate amount of add. Experiments found that the binder amount and the amount of mica is increased within a certain range, which can effectively improve the frequency characteristics of powder cores, reducing the high-frequency loss; when the mica content is 1.0%, and the silicone resin content of 3.5%, and magnetic core integrated magnetic best; pressure is to ensure the powder cores to obtain good magnetic properties and mechanical properties of the base, increasing pressure is beneficial for increasing the density of the sample, to improve permeability, to improve the crush strength; but the pressure is too large will also adversely impact of stress and defects within the powder cores increase, so sure you want to consider the capacity of the insulating layer pressure heat treatment also affect the magnetic properties important; When the the molding pressure 18t/cm2 when integrated magnetic powder cores best; process, heat treatment can increase the magnetic permeability of the sample, and to reduce the eddy current loss; case to ensure that the insulating layer is not ablated, as much as possible to improve the heat-treatment temperature; Furthermore, the heat treatment requires a certain holding time, so that the inside of the powder cores completely stress release; 660 ℃ × 1h heat treatment process, the best; samples magnetic powder cores made of different powder particle size magnetic particle performance, semolina powder cores made of high permeability, eddy current loss, the sample constant magnetic permeability. Cohen permeability obtained in that the control of powder particle size and particle size distribution, higher density of the powder core; proportion of the appropriate increase in the fine powder to help reduce eddy current losses, and improve the high frequency performance of powder cores; When the particle size ratio: -100 - 150 projects accounted for 4%, from -150 to 250 mesh, 8%, 34% -250 - 320 mesh, -320 mesh, 54% when the sample magnetic best; using the optimization process: the insulating agent mica content to 1.0%, adhesive silicone resin content of 3.5%, the molding pressure 18t/cm2, heat treatment 660 ° C × 1h granularity ratio: -100 to 150 mesh (4%), accounting for 8% of -150 to 250 mesh, -250 to 320 mesh accounted for 34%, -320 mesh, 54%, the obtained powder cores performance: permeability 127.94 per unit mass loss 12.439w/kg, strength of 28.5 MPa.