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High induction grain-oriented la-doped strontium ferrite and preparation method thereof

A strontium ferrite, lanthanum doping technology, applied in chemical instruments and methods, iron compounds, inorganic chemistry, etc., can solve the problems of lowering the sintering temperature, achieve low fusion-assisted sintering temperature, short holding time, and simple improvement process Effect

Inactive Publication Date: 2016-05-25
HAIAN INST OF HIGH TECH RES NANJING UNIV +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Third, the molten salt induction effect solves the problem of rare earth lanthanum ion substitution and doping, which affects the lattice energy and leads to the appearance of non-magnetic phases, which promotes the migration of rare earth lanthanum ions and reduces the sintering temperature, which is beneficial to the preparation of single-phase lanthanum ion doping Strontium ferrite

Method used

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  • High induction grain-oriented la-doped strontium ferrite and preparation method thereof
  • High induction grain-oriented la-doped strontium ferrite and preparation method thereof
  • High induction grain-oriented la-doped strontium ferrite and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] This experiment is to prepare undoped strontium ferrite powder, the specific steps are as follows.

[0022] Weigh 1.058g strontium nitrate (Sr(NO 3 ) 2 ) and 24.24g iron nitrate (Fe(NO 3 ) 3 9H 2 O) put into the beaker of 1000mL as raw material, and add 13.448g citric acid as complexing agent, dissolve with appropriate amount of distilled water. Heat the obtained mixed solution in a water bath at 80°C to completely volatilize the water, then heat the dry gel at 200-300°C, through the self-propagating combustion of citric acid, react between nitrate and citric acid to form strontium For ferrite precursor powder, mix the generated precursor powder with anhydrous sodium sulfate uniformly at a certain mass ratio of 1:1, then put it into a cylindrical crucible, and heat up at 1100 °C at a rate of 10 / min in an air atmosphere. ℃ sintering for 2 hours to obtain a dense block; put the block strontium ferrite sintered material into distilled water for ultrasonic dissolution,...

Embodiment 2

[0024] This experiment is to prepare lanthanum-doped strontium ferrite powder with x=0.15, the specific steps are as follows.

[0025] Weigh 0.896g strontium nitrate (Sr(NO 3 ) 2 ), 24.24g iron nitrate (Fe(NO 3 ) 3 9H 2 O) and 0.277g lanthanum nitrate (La(NO 3 ) 3 ·nH 2 O) put into the beaker of 1000mL as raw material, and add 20.17g citric acid as complexing agent, dissolve with appropriate amount of distilled water. Other preparation processes are the same as in Example 1. The prepared ultra-fine lanthanum-doped strontium ferrite powder is mixed with a certain quality of epoxy resin and placed in a mold, solidified at room temperature in a 5KOe magnetic field, the remanence ratio of the oriented sample reaches 71.2%, and the hysteresis loop at room temperature is shown in figure 2 .

Embodiment 3

[0027] This experiment is to prepare lanthanum-doped strontium ferrite powder with x=0.2, the specific steps are as follows.

[0028] Weigh 0.846g strontium nitrate (Sr(NO 3 ) 2 ), 24.24g iron nitrate (Fe(NO 3 ) 3 9H 2 O) and 0.37g lanthanum nitrate (La(NO 3 ) 3 ·nH 2O) put into the beaker of 1000mL as raw material, and add 20.17g citric acid as complexing agent, dissolve with appropriate amount of distilled water. Other preparation processes are the same as in Example 1. It can be seen from the XRD measurement of the unoriented powder that the molten salt assisted sintered lanthanum-doped strontium ferrite powder has no non-magnetic phase, see image 3 .

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Abstract

The invention relates to high induction grain-oriented la-doped strontium ferrite and a preparation method of the high induction grain-oriented la-doped strontium ferrite. The preparation method is characterized by comprising the following steps of preparing a rare-earth la ion-doped strontium ferrite precursor through a sol-gel method; preparing single-phase la ion-doped strontium ferrite by adopting molten salt auxiliary sintering; firstly carrying out mechanical ball milling to mix the precursor with a sodium sulfate mixture for one hour, wherein a preferable sintering process is that heat preservation is carried out for 2 hours in an air atmosphere at the temperature of 1000 to 1100 DEG C and a temperature rising speed of 10 / min; dissolving sulfate by adopting distilled water, preferably carrying out ultrasonic dissolution for 3 to 5 times, and drying at 100 DEG C, thus obtaining ultra-fine la-doped strontium ferrite powder. According to the preparation method disclosed by the invention, the cost of used raw materials is cheap, the preparation technology is mature, the molten salt auxiliary sintering temperature is lower, the heat preservation time is short, and the energy source is saved; a prepared ferrite oxide is Sr1-xLaxFe12O19, and x is larger than or equal to 0 and smaller than or equal to 0.2, which are all single-phase hexagonal crystals; in an optimal doping rate x is equal to 0.15, the saturated magnetization strength is 69.52 emu / g, the maximum coercive force is up to 6252Oe, and a remanence ratio is up to 71.2 percent; the ultra-fine la-doped strontium ferrite powder is excellent in magnetic orientation performance, excellent in magnetic performance and suitable for bonded magnets, automobile motors and electromagnetic shielding and magnetic recording materials.

Description

technical field [0001] The invention belongs to the field of magnetic materials, in particular to a lanthanum-doped strontium ferrite with high magnetic orientation and a preparation method thereof, in particular to a single-phase hexagonal lanthanum-doped strontium ferrite powder prepared by a molten salt assisted sintering technology. Background technique [0002] Permanent ferrite has the advantages of wide range of raw materials, good chemical stability, low price and high coercive force. It is widely used in the fields of electronics industry, household appliances and electrical equipment, such as microwave absorbing materials, magnetic recording materials, motors and bonding magnetic poles. In particular, M-type strontium ferrite magnets with large magnetocrystalline anisotropy have mature preparation technology and low cost. In recent years, many articles and technologies have achieved high remanence and high coercive force by improving the synthesis route, sintering...

Claims

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Application Information

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IPC IPC(8): C01G49/00
CPCC01G49/0036C01G49/0054C01P2002/72C01P2006/42
Inventor 雷成龙唐少龙周连明潘冠军孟祥康都有为
Owner HAIAN INST OF HIGH TECH RES NANJING UNIV