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Method for secondary coating of a magnetic powder core with phosphoric acid and nano calcium carbonate

A technology of nano-calcium carbonate and magnetic powder cores, which is applied in the direction of magnetic objects, magnetic materials, and inorganic materials, can solve the problems of poor bonding effect of inorganic adhesives, unstable performance of magnetic powder cores, and poor DC bias performance. Achieve the effects of less insulation, good DC bias performance, and improved weather resistance

Active Publication Date: 2021-01-05
JIANGXI AITE MAGNETS +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the above-mentioned thin and uneven cladding layer of the traditional magnetic powder core process, resulting in unstable magnetic properties, the use of organic adhesives will lead to unstable performance of the magnetic powder core, poor DC bias performance, and poor bonding effect using inorganic adhesives , leading to the problem of low appearance qualification rate, the invention provides a method for secondary coating of magnetic powder cores with phosphoric acid and nano-calcium carbonate

Method used

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  • Method for secondary coating of a magnetic powder core with phosphoric acid and nano calcium carbonate
  • Method for secondary coating of a magnetic powder core with phosphoric acid and nano calcium carbonate
  • Method for secondary coating of a magnetic powder core with phosphoric acid and nano calcium carbonate

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Experimental program
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Effect test

Embodiment 1

[0031] Get phosphoric acid 100g, deionized water 100g, mix homogeneously, prepare the phosphoric acid solution for use; Get the FeSiAl (chemical composition is iron 87.8%, silicon 6.8% and aluminum 5.4% that the gas atomization process of 38 μ m is made) ) 1000g of magnetic powder, put it into the coating furnace and start stirring; add the phosphoric acid solution into the coating furnace, and continue stirring for 30 minutes; add 20g of nano-calcium carbonate with a particle size of less than 100nm, and continue stirring for 30 minutes; the temperature of the coating furnace is raised to 120°C, Continue to stir until dry to obtain the pretreated magnetic powder; add 0.3% zinc stearate based on the weight of the pretreated magnetic powder, and stir evenly; press the pressure of 2300MPa to form Annular magnetic powder core; keep warm for 30 minutes under the protection of 700°C and nitrogen (nitrogen purity ≥ 99.9%), and perform annealing heat treatment to obtain phosphoric aci...

Embodiment 2

[0037] Get phosphoric acid 5g, deionized water 50g, mix uniformly, prepare the phosphoric acid solution for use; Get the FeSi (chemical composition is iron 94.5%, silicon 5.5%) magnetic powder 1000g that particle average particle size is 35 μ m, put into cladding furnace Start the stirring; add the phosphoric acid solution into the coating furnace, and continue stirring for 35 minutes; add 1 g of nano-calcium carbonate with a particle size of less than 100 nm, and continue stirring for 35 minutes; raise the temperature of the coating furnace to 120 ° C, continue stirring until dry, and obtain the pretreated Magnetic powder; add 0.4% zinc stearate of the magnetic powder weight after pretreatment, stir; Press the pressure of 1500MPa to be pressed into the annular magnetic powder core of external diameter 27.0mm, internal diameter 14.7mm, height 11.0mm; At 720 ℃ and nitrogen ( The purity of nitrogen is ≥99.9%), and the temperature is kept for 45 minutes under protection, and annea...

Embodiment 3

[0043] Get phosphoric acid 20g, deionized water 100g, mix uniformly, prepare the phosphoric acid solution for use; Get the FeNi (chemical composition is iron 54.5%, nickel 45.5%) magnetic powder 1000g that particle average particle size is 30 μ m, put into cladding furnace Start stirring; add the phosphoric acid solution into the coating furnace, and continue stirring for 40 minutes; add 5 g of nano-calcium carbonate with a particle size of less than 100 nm, and continue stirring for 40 minutes; heat up the coating furnace to 130 ° C, continue stirring until dry, and obtain the pretreated Magnetic powder; add 0.4% zinc stearate of the magnetic powder weight after pretreatment, stir; Press the pressure of 2100MPa to be pressed into the annular magnetic powder core of external diameter 27.0mm, internal diameter 14.7mm, height 11.0mm; At 740 ℃ and nitrogen ( Purity of nitrogen (≥99.9%) is kept under protection for 60 minutes, annealing heat treatment is carried out, and phosphoric...

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Abstract

The invention discloses a method for secondary coating of a magnetic powder core with phosphoric acid and nano calcium carbonate, which comprises the following steps: stirring and mixing magnetic powder and a phosphoric acid solution, reacting to obtain a Fe(H2PO4)2 primary coating layer on the surface of the magnetic powder, adding nano calcium carbonate, stirring and mixing, and reacting to obtain a Ca(H2PO4)2 secondary coating layer on the surface of the magnetic powder. According to the invention, double-layer coating is carried out on the surface of the magnetic powder, and nano calcium carbonate with high resistivity is filled among magnetic powder particles, so that the insulativity is very good; the use amount of insulators achieving the same insulation effect is small, and the direct-current bias performance is good; the used coating binding material is inorganic materials such as nano calcium carbonate and monocalcium phosphate Ca(H2PO4)2 generated by reaction, the binding performance is good, the forming is easy, the appearance qualification rate is high, meanwhile, the weather resistance is greatly improved, and the cost is greatly reduced; and the preparation equipmentis simple, easy to operate, low in cost and particularly suitable for industrial large-batch and large-scale production.

Description

technical field [0001] The invention relates to the technical field of magnetic powder core preparation, in particular to a method for secondary coating of a magnetic powder core with phosphoric acid and nanometer calcium carbonate. Background technique [0002] In the traditional magnetic powder core coating process: [0003] In the first step, phosphoric acid is generally used as a passivating agent and added to the magnetic powder. The iron and phosphoric acid in the magnetic powder are carried out through the following reaction: Fe+2H 3 PO 4 =Fe(H 2 PO 4 ) 2 +H 2 . Fe(H 2 PO 4 ) 2 Coating on the surface of metal particles plays an insulating role, but the disadvantages are: 1. When phosphoric acid and magnetic powder react, the surface of the magnetic powder reacts first, and after the reaction reaches a certain level, the surface is covered by Fe(H 2 PO 4 ) 2 Covered, unable to continue the reaction, resulting in excess phosphoric acid. 2. Fe(H 2 PO 4 ) ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01F1/24H01F41/02
CPCH01F1/24H01F41/02H01F41/0246H01F1/147
Inventor 张勉团毛圣华陈俊杰皮金斌温余远金鑫
Owner JIANGXI AITE MAGNETS
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