| Metal soft magnetic powder cores are widely used in the industry fields of electric power,electronics and communication,due to their higher saturation magnetic induction strength,lower eddy current loss,and high cost performance.However,with the rapid development of information technology in recent years,the performance requirements for electromagnetic components have become higher and higher,and soft magnetic powder cores prepared by traditional processes cannot meet the demand.Therefore,in this thesis thehigh-efficiency preparation strategyand its mechanism were explored for obtaining ferro-aluminum and ferro-silicon soft magnetic magnetic powder cores,in order to lay the theoretical and technogical bases particle size of for developingthe magnetic powder core products with low loss,high magnetic permeability,high quality factor,excellent DC superposition characteristics and good formability.The bonding technology is of great importance for obtaining magnetic powder cores,and the binders remarkably affects the formability and various magnetic properties of the prepared magnetic powder cores.In this thesis,Al2(SO4)3 modified silica sol and Al(H2PO4)3were selected as the binders.The results are as follows:(1)When the amount of the Al2(SO4)3 modifier is increased from 0 to 0.5%,the effective magnetic permeability of the magnetic powder core at 100 k Hz gradually is decreased from 100.2 to 50.8,the DC superimposed characteristics is increased from 60%to 81%,the quality factor Q is increased from 53 to 80,at 100 k Hz,the magnetic loss at 50 m T is decreased the magnetic loss from 500 m W/cm3 to 402 m W/cm3,the flexural strength is increased from 8.78 k Pa to 19.04 k Pa,and then decreased to 16.28 k Pa.the magnetic powder core sample prepared shows the highest overall performance when the amount of the added Al2(SO4)3modifier is 0.2%.(2)when the amount of the Al(H2PO4)3 binder is increased from 1.5%to 2.0%,the effective permeability of the magnetic powder core sample at 100 k Hz is gradually decreased from 79.8 to 65.2,with the DC superimposed characteristic increased from 62.7 to 78,and the quality factor Q increased from 54 to67 at the beginning and then decreased to 61,at 100 k Hz,the magnetic loss at a magnetic flux density of 50 m T decreased from 410 to 375 m W/cm3 and then increased to 430 m W/cm3,the flexural strength increased from 16.1 k Pa to 21.6 k Pa,and deceased to 13.3 k Pa.The magnetic powder core sample shows the highest overall performance when the amount of the added Al(H2PO4)3 binder is 1.8%.Commercially available 270060 crushing method iron silicon aluminum soft magnetic powder core is not strong in saturation resistance,and has low mechanical strength in actual use.Usually at a frequency of 100 k Hz and a DC magnetic field of100 Oe,the DC superposition characteristic is between 70%and 80%.Due to the low magnetic permeability,the thick coating and the amount of inorganic material added,the bending strength is generally only 10 k Pa.In this paper,through the use of Zn(H2PO4)2 surface-modified silicon fine powder as a filler and binder,the effect of different Zn(H2PO4)2 addition on the magnetic properties and flexural strength of the270060 type crushing iron silicon aluminum powder core is explored.The results show that:when the amount of Zn(H2PO4)2 is 15wt%of the mass of silicon fine powder,the frequency is in the range of 1 to 1 000 k Hz,and the magnetic permeability is about24.8;when the frequency is 100 k Hz,under the application of 100 Oe DC magnetic field,the magnetic powder The DC superposition percentage of the core is close to85%;the quality factor Q value reaches 141 at a frequency of 200 k Hz;the magnetic loss at a frequency of 50 k Hz and a magnetic flux density of 100 m T is less than 175m W/cm3;in addition,the bending strength of the magnetic powder core Reached 19.7k Pa.The prepared 270026 type ferrosilicon magnetic powder core samples have far better magnetic properties and mechanical strength than the conventional commercial270026 type ferrosilicon magnetic powder core products.The particle size of magnetic powder is one of the main factors influencing the magnetic properties of the magnetic powder core.By adjusting the particle size distribution of the magnetic powder,the eddy current loss and quality factors of the magnetic powder core prepared can be greatly improved.In this thesis,the four groups of magnetic powder samples with the particle size of+200 mesh,-200-+250 mesh,-250-+400 mesh,and-400 mesh were used to improve the effective permeability,quality factor Q and magnetic loss of 270060 iron-silicon-aluminum magnetic powder core through orthogonal experiments.The results are as follows:the magnetic powder is composed of 33wt%of+200-mesh powder,33wt%of-200--+250-mesh powder,33wt%of-250-+400-mesh powder,1wt%of-400-mesh powder results in the magnetic powder core sample with the highest magnetic permeability of 30.4;the magnetic powder consists of 11wt%of+200-mesh powder,11wt%of-200-+250-mesh,33wt%of-250-mesh-+400-mesh powder,45wt%of-400-mesh powder leads to the magnetic power core with the lowest magnetic permeability of 25.83.The influence of the particle size range on the magnetic permeability is ranked as:+200mesh>-200-+250 mesh>-250-+400 mesh>-400 mesh.Clearly,the higher proportion of large particle magnetic powder in the magnetic powder core,the higher effective permeability of the magnetic powder core.The magnetic powder core derived from11wt%of+200-mesh powder,11wt%of-200-+250-mesh powder,11wt%of-250-+400-mesh powder,67wt%-400-mesh powder shows the highest DC superposition characteristics,and its DC superposition reaches as high as 85.14%through verification experiments.The influence of the particle size range on the DC superposition characteristics is ranked as:-200-+250 mesh(29)-250+400 mesh(29)+200mesh.The magnetic powder core derived from 11wt%of+200-mesh powder,11wt%of-200-+250-mesh powder,22wt%of-250-+400–mesh powder,56wt%of-400-mesh powder exhibitsthe highest quality factor of 102.5,and the particle size range of-200 mesh through variance analysis shows a significant impact on the DC superposition characteristics. |
PDF Full Text Request