CN-121974670-A - Improved method for preparing manganese zinc ferrite nano-particles

Abstract

The invention belongs to the technical field of soft magnetic ferrite, and particularly relates to a preparation method of manganese zinc ferrite nano particles with safety, high performance and low cost. The invention provides an improved sol-gel preparation method of manganese zinc ferrite nano particles, which takes N, N-Dimethylformamide (DMF) as a solvent, polyvinylpyrrolidone (PVP) as a dispersing agent, and zinc acetate is adopted to replace the traditional zinc nitrate raw material, so that the use of easy-to-make explosion chemicals is avoided. The method has the advantages of simple process, low sintering temperature, short time, low energy consumption and cost, simple equipment requirement and the like, and is suitable for large-scale industrial production.

Inventors

• LU RUIE
• WEN JIAN
• LIANG ZHONGWEI
• LIU GUIYUN
• XIAO JINRUI
• LEI QUN
• JIANG LINGLI

Assignees

• 广州大学

Dates

Publication Date

20260505

Application Date

20251231

Claims (10)

1. 1. A method for preparing manganese zinc ferrite nanoparticles, comprising the steps of: S1, weighing manganese nitrate, zinc acetate and ferric nitrate according to stoichiometric ratio of Mn, zn and Fe in molecular formula Mn x Zn 1-x Fe 2 O 4 of the manganese zinc ferrite, adding N, N-dimethylformamide solution, stirring and dissolving to obtain metal ion solution; s2, adding polyvinylpyrrolidone into the metal ion solution, and continuously stirring to obtain stable and uniform sol; s3, drying and grinding the sol to obtain precursor powder; S4, sintering the precursor powder for the first time in an air atmosphere, and then sintering the precursor powder for the second time in a nitrogen atmosphere to obtain manganese zinc ferrite nano particles; wherein the temperature of the second sintering is higher than the temperature of the first sintering.
2. 2. The method of claim 1, wherein the manganese nitrate is manganese nitrate tetrahydrate, the zinc acetate is zinc acetate dihydrate, and the iron nitrate is iron nitrate nonahydrate.
3. 3. The method according to claim 1, wherein the amount of N, N-dimethylformamide is 4-6 ml per millimole of manganese zinc ferrite added.
4. 4. The method according to claim 1, wherein the molar ratio of polyvinylpyrrolidone to manganese zinc ferrite is 1:60-100.
5. 5. The method according to claim 1, wherein the drying is at 100-150 ℃ for 4-6 hours.
6. 6. The method of claim 1, wherein the temperature of the first sintering is 300-500 ℃ and the temperature of the second sintering is 600-800 ℃.
7. 7. The method of any one of claims 1-6, wherein the time for the first sintering is 1-2 hours and the time for the second sintering is 0.5-2 hours.
8. 8. The method of claim 1, wherein the first sintering is performed at a temperature of 500 ℃ for 2 hours and the second sintering is performed at a temperature of 600 ℃ for 1 hour.
9. 9. Manganese zinc ferrite nanoparticles prepared according to the method of any one of claims 1-8.
10. 10. The manganese-zinc-ferrite nanoparticle according to claim 9, wherein the saturation magnetization of the manganese-zinc-ferrite nanoparticle is 60-80 emu/g and the particle size is 60-160 nm.

Description

Improved method for preparing manganese zinc ferrite nano-particles Technical Field The invention belongs to the technical field of soft magnetic ferrite, and particularly relates to an improved sol-gel method for preparing manganese zinc ferrite nano particles. Background The Mn-Zn ferrite as one kind of key soft magnetic material has excellent soft magnetic performance including high initial magnetic conductivity, high resistivity, low loss, high saturation magnetic flux density, etc. and is thus used widely in high frequency power electronic device, such as transformer, inductor, filtering magnetic core, magnetic head, etc. and is one core material for promoting the development of high frequency, miniaturization and high energy efficiency. Therefore, the method and the process for preparing the manganese zinc ferrite are simple, safe, low in energy consumption and capable of being scaled are developed, and have important significance for further application in electronic devices. Currently, the main preparation methods of the manganese zinc ferrite comprise a solid phase sintering method, a coprecipitation method, a hydrothermal method and a sol-gel method. Except the solid phase method, the rest belongs to wet chemical technology. The solid phase sintering process uses metal oxide as material and includes ball milling, pre-sintering, secondary ball milling, forming, high temperature sintering and other steps. The method needs to be subjected to high-temperature treatment (900-1300 ℃) and ball milling for many times, the energy consumption is high, the flow is complex, the obtained powder is low in purity, poor in uniformity and easy to agglomerate, and the particle size is usually tens of microns. The coprecipitation method is to react metal salt solution containing Mn, zn and Fe with a precipitant, and then to obtain the product through ageing, filtering, washing, drying and sintering. But the precipitate is difficult to sufficiently wash and filter, is easy to cause component segregation, has long reaction period and is more complex in process flow. The hydrothermal method is used for carrying out high-temperature high-pressure reaction in an autoclave, so that nano-scale powder can be prepared, but the preparation method is limited by the volume of the autoclave and is difficult to realize large-scale production. Meanwhile, the method can involve toxic reagents and generate harmful byproducts and waste materials, and certain environmental protection pressure exists. In the sol-gel method, metal salt is generally dissolved in water or alcohol solvent, chelating agent is added to form uniform sol, and ferrite is obtained through drying and sintering. The method has the advantages of simple equipment, easy regulation and control of process parameters and low energy consumption, and is suitable for laboratory and pilot scale preparation. However, existing sol-gel techniques still face a number of limitations. For example, chinese patent CN109775761B, "a method for preparing manganese-zinc ferrite nanoparticles", proposes a method for preparing manganese-zinc ferrite nanoparticles by sintering at low temperature of 300-500 ℃, but the obtained product has lower crystallinity, limited improvement of saturated magnetic flux density, and easy generation of Fe 2O3 impurity phase at higher temperature, damaging magnetic properties, and difficulty in meeting high power application requirements. Another patent application CN111471342a "a manganese zinc ferrite-carbon nanotube grafted polyaniline wave-absorbing coating and its preparation method" discloses a preparation method of manganese zinc ferrite-carbon nanotube grafted polyaniline wave-absorbing coating, in which chlorine salts such as FeCl 3、MnCl2 and ZnCl 2 are used to prepare manganese zinc ferrite nanofibers, but the method mainly focuses on the structural design and wave-absorbing performance of the composite material, and the basic magnetic performance of the composite material is not systematically explored. In addition, although the patent CN1066565C "preparation method of ultrafine manganese zinc ferrite powder" successfully prepares ultrafine manganese zinc ferrite powder with excellent magnetic properties, the process flow of the preparation method comprises a plurality of steps of filtering, washing, organic alcohol exchange, solvent removal by nitrogen purging, sintering and the like, the operation is complex, and the large-scale production is difficult to realize. Therefore, a method which is simple in process, low in cost, energy-saving and environment-friendly and can stably prepare the high-performance manganese zinc ferrite nano particles is still lacking, and the method becomes a key bottleneck for further application of the material. In view of this, the present invention has been made. Disclosure of Invention The invention aims to solve the problems of complex preparation process, high reaction temperature, poor environmental protection