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Method for improving coercivity of permanent ferrite

A technology of permanent magnet ferrite and coercivity, applied in the field of improving the coercivity of permanent magnet ferrite, can solve problems such as decline, and achieve the effects of low cost, improved magnetic performance, and enhanced competitiveness

Inactive Publication Date: 2012-04-11
SINOSTEEL ANHUI TIANYUAN TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of these additives are: CaCO 3 Additives such as , CaO and some rare earth oxides increase the remanence while the coercive force and intrinsic coercive force of the material also decrease; Al 2 o 3、 SiO 2 、Cr 2 o 3、 SrCO 3 、H 3 BO 3 Additives such as additives increase the coercive force and intrinsic coercive force of the material, while the remanence also decreases sharply.

Method used

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  • Method for improving coercivity of permanent ferrite

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] 1), ingredients: as shown in Table 1.

[0019] 2) Ball milling: use a roller mill for secondary ball milling, the steel balls used are bearing steel balls with a diameter of 5-10 mm, and the ball milling time is 15-20 hours; the mass percentage of material, balls and water is 1:15 : 2; The particle size of the secondary ball mill is tested with a laser particle size analyzer, and its D50 is controlled within the range of 0.80~0.95μm;

[0020] 3) Compression molding: Press the slurry after ball milling with a magnetic material hydraulic press. The diameter of the pressed blank is 30-40 mm, the height is 15-25 mm, and the density is 3.1-3.3 g / cm 3 ;The water content of the slurry before pressing is controlled at 33~38%;

[0021] 4) Sintering: Use a program-controlled box-type electric furnace to sinter the blank. The specific sintering process is as follows: 180°C / 1.0h+380°C / 1.0h+600°C / 1.0h+850°C / 1.0h+1100°C / 1.0h +1175°C / 1.5h.

[0022] 5) Grinding: Grinding the upper a...

Embodiment 2

[0028] Example 2: Pre-sintered material B was used for sintering, and the sintering process was 180°C / 1.0h+380°C / 1.0h+600°C / 1.0h+850°C / 1.0h+1100°C / 1.0h+1185°C / 1.5h. Other steps are the same as in Example 1. The specific properties of the product prepared by using calcined material B are shown in Table 3 below:

[0029] Table 3 Specific properties of products prepared from calcined material B

[0030] Sample type Br(kGs) Hcb(kOe) Hcj(kOe) (BH)m(MGO) B1 4.123 2.552 2.658 4.158 B2 4.111 3.089 3.302 4.067 B3 4.126 3.143 3.343 4.105

[0031] The calcined material B is according to the formula in Table 1, and the sintering temperature of the three formulas of B1, B2 and B3 is 1185°C. It can be seen from Table 3 that compared with B1, the remanence of formula B2 is only slightly reduced by 12Gs, while the coercive force of the material is increased by 537Oe, and the intrinsic coercive force is increased by 644Oe; compared with B1, the...

Embodiment 3

[0033] Example 3: Pre-sintered material C is used for sintering, and the sintering process is 180°C / 1.0h+380°C / 1.0h+600°C / 1.0h+850°C / 1.0h+1100°C / 1.0h+1175°C / 1.5h. Other steps are the same as in Example 1. The specific properties of the product prepared by using calcined material C are shown in Table 4 below:

[0034] Table 4 Specific properties of products prepared from calcined material C

[0035] Sample type Br(kGs) Hcb(kOe) Hcj(kOe) (BH)m(MGO) C1 3.943 3.154 3.306 3.852 C2 3.930 3.543 3.764 3.775 C3 3.935 3.637 3.925 3.781

[0036]Pre-sintered material C follows the formula in Table 1, and the sintering temperature of the three formulas of C1, C2 and C3 is 1175°C. It can be seen from Table 4 that compared with C1, the remanence of formula C2 is only slightly reduced by 13Gs, while the coercive force of the material is increased by 389Oe, and the intrinsic coercive force is increased by 458Oe; compared with C1, the remanent m...

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Abstract

The invention discloses a method for improving coercivity of permanent ferrite by adding an additive without reduction of residual magnetism, which specifically comprises the following steps of: 1), preparing materials, namely, adding two to six of CaCO3, SrCO3, SiO2, Al2O3, H3BO3 and Cr2O3 in secondary process on the basis of iron strontium oxide once pre-sintered material, and adding an additive with formula of RxAlyFezOm, wherein R is mixture of two or more of Pr, Bi, Gd, Nd, Cu, Cr and Co; 2), ball milling; 3), pressing and forming; 4), sintering; and 5), grinding. The invention has the following positive effects that: with respect to the same pre-sintered material, coercivity and intrinsic coercivity of the material are improved by 300-700Oe without reduction of residual magnetism after the additive RxAlyFezOm is added.

Description

technical field [0001] The invention relates to a method for increasing the coercive force of permanent ferrite, in particular to a method for increasing the coercive force of permanent ferrite by adding an additive without reducing the remanence. Background technique [0002] With the rapid development of the automobile industry, high-performance automobile motors have higher and higher requirements on the performance of permanent ferrite. In order to meet the market demand, in recent years, after the Japanese TDK company, the ace company in the ferrite industry, launched the FB9 and FB12 series of high-performance permanent magnet ferrite products, there has been a rapid development of high-tech ferrite companies in the global ferrite industry. Performance permanent ferrite boom. Various manufacturers have explored ways to improve the magnetic properties of permanent ferrites from the aspects of raw materials, secondary additions, and production processes. The microstruc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/26C04B35/622
Inventor 杨玉杰曹晓希裴晓东王勇
Owner SINOSTEEL ANHUI TIANYUAN TECH
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