Two-time compounding addition method for improving coercivity of permanent magnetic strontium ferrite

A technology of composite addition and strontium ferrite, applied in the direction of inorganic material magnetism, can solve the problems of cost increase, complicated preparation process, time-consuming and laborious, etc., and achieve the effect of low price and improved intrinsic coercive force

Inactive Publication Date: 2016-11-23
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The Chinese invention patent (publication number CN102408229A) discloses a method for improving the coercive force of permanent magnet ferrite, which has a certain effect on improving the magnetic properties of the magnet, but the additive R x al y Fe z o m The preparation process is complicated, time-consuming and labor-intensive, and the additives added at the same time contain rare earth elements such as cobalt and praseodymium, which greatly increases the cost

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  • Two-time compounding addition method for improving coercivity of permanent magnetic strontium ferrite
  • Two-time compounding addition method for improving coercivity of permanent magnetic strontium ferrite
  • Two-time compounding addition method for improving coercivity of permanent magnetic strontium ferrite

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Embodiment 1

[0031] A secondary composite addition method for improving the coercive force of permanent magnet strontium ferrite, the specific steps are as follows: on the basis of the primary calcined material of strontium ferrite, perform secondary composite addition, and the secondary composite additive is first pretreated , the mass percentage of the total weight is 1%, and the pretreated secondary compound additive includes 0.2% CaCO 3 , 0.15% Al 2 o 3 , 0.5%Cr 2 o 3 , 0.1%H 3 BO 3 , 0.05% SiO 2 ·nH 2 O. Add dispersant C 6 h 14 o 6 , HCOOH and Ca(C 6 h 11 o 7 )2 The weight percent of the mixture is 7%. Secondary ball milling is carried out in the ball mill, the steel balls used are bearing steel balls with a diameter of 5.50-7.50mm, and the ball milling time is ≥18h; the mass percentage of material, ball and water is 1:(13-16):(1.6-1.9 ), the slurry particle size after secondary ball milling is ≤0.9μm. Transfer the slurry from the second ball mill to a dehydrator for d...

Embodiment 2

[0033] Compared with Example 1, the weight percent of the secondary composite additive is 3%, and includes 1.0% CaCO in the secondary composite additive after pretreatment 3 , 0.15% Al 2 o 3 , 0.6%Cr 2 o 3 , 0.25%H 3 BO 3 ,, 0.2% SiO 2 ·nH 2 O, 0.3% MgO, 0.2% Mn 2 o 3 , 0.3% NaCl.

[0034] figure 1 It is the demagnetization curve figure of the present embodiment, as can be seen from this figure, the magnetic performance of embodiment 2 is: B r =412.7mT,H cb =310.6kA / m, H cj =338.6kA / m, (BH) max =33.9kJ / m 3 .

Embodiment 3

[0036] Compared with Example 1, the percentage of the secondary composite additive is 5%, including 1.0% CaCO in the secondary composite additive after pretreatment 3 , 0.4% Al 2 o 3 , 1.0%Cr 2 o 3 , 0.6%H 3 BO 3 ,, 0.6% SiO 2 ·nH 2 O, 0.4% MgO, 0.5% Mn 2 o 3 , 0.5% KCl. The magnetic property of embodiment 3 is: B r =390.8mT,H cb =300.3kA / m, H cj =319.2kA / m, (BH) max =30.4kJ / m 3 .

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Abstract

The invention discloses a two-time compounding addition method low in price. The intrinsic coercivity of a material can be improved on the premise of not reducing residual magnetism. The method specifically includes the steps of firstly, preparing materials, wherein on the basis of a strontium ferrite pre-sintering material, two-time compounding addition is conducted; secondly, conducting ball-milling, wherein a dispersing agent is added during ball-milling, and the dispersing agent includes one or more of C6H14O6, HCOOH, Ca(C6H11O7)2 and C6H7NaO6; thirdly, conducting dehydrating; fourthly, conducting forming; fifthly, conducting sintering; sixthly, conducting grinding and performance testing. The additives related in two-time compounding addition are low in price, rare earth or noble metallic oxide high in price is not added, and on the premise of ensuring that the residual magnetism of the material is not changed, the intrinsic coercivity can be improved by about 136-144 kA/m and reaches 336-344 kA/m.

Description

technical field [0001] The invention belongs to the field of preparation of permanent magnet ferrite in functional materials, and in particular relates to a secondary compound addition method for improving the coercive force of permanent magnet strontium ferrite. Background technique [0002] At present, the global demand for permanent ferrite is increasing year by year, and China, as a major user of permanent ferrite, maintains a faster growth in demand. The M-type permanent magnet ferrite industry has developed rapidly in recent decades, and China's output has risen to the forefront of the world, but the problem is that the permanent magnet ferrite produced by most domestic enterprises is still at a low level for a long time. Moreover, the utilization rate of raw materials is low, and the production technology is far behind other countries. Therefore, improving the performance of the product and improving the production process have always been the focus of research in th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/26C04B35/622C04B35/626H01F1/10
CPCC04B35/2625C04B35/2633C04B35/2658C04B35/2691C04B35/622C04B35/62605C04B2235/3217C04B2235/3241C04B2235/3409C04B2235/3418H01F1/10
Inventor 王寅岗张胜安
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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