CN102485692B

CN102485692B - Preparation method of two-dimensional sheet-shaped barium ferrite

Info

Publication number: CN102485692B
Application number: CN 201010572921
Authority: CN
Inventors: 孟锦宏; 孙杰; 刘宇; 曹晓晖; 王文举
Original assignee: Shenyang Ligong University
Current assignee: Shenyang Ligong University
Priority date: 2010-12-06
Filing date: 2010-12-06
Publication date: 2013-08-07
Anticipated expiration: 2030-12-06
Also published as: CN102485692A

Abstract

The invention provides a preparation method a two-dimensional sheet-shaped barium ferrite. The two-dimensional sheet-shaped barium ferrite has a chemical formula of BaFe12O19. The preparation method comprises the following steps of orderly or simultaneously adding a soluble barium salt-ferric salt mixed saline solution and a sodium carbonate-sodium hydroxide mixed alkali solution into a BaFe12O19 raw material obtained by any method to obtain a precursor, and calcinating the precursor at a temperature of 900 to 1100 DEG C to obtain BaFe12O19 power. The BaFe12O19 power has a nanoscale particle size. The particle of the BaFe12O19 power has an obvious two-dimensional hexagonal shape or a nearly hexagonal sheet shape, and can be adjusted in size by reaction conditions. The preparation method provided by the invention has simple and easily-controlled processes, is suitable for industrial production and realizes stable product performances. The BaFe12O19 power obtained by the preparation method is suitable for the fields of magnetic materials and electromagnetic wave absorption.

Description

A kind of preparation method of two-dimensional sheet barium ferrite

Technical field

The present invention relates to a kind of BaFe that possesses exemplary two dimensional sheet shape characteristic ₁₂O ₁₉The preparation method of powder.

Background technology

Barium ferrite (BaFe ₁₂O ₁₉) be a kind of hexaplanar hard magnetic material, with its excellent magnetic performance and good chemical stability, be widely used in magnetic material and absorbing material field.In recent years the performance and its pattern that studies show that barium ferrite are closely related, and when containing the sheet of some or club shaped structure in the particle, the suction ripple usefulness of barium ferrite improves and sheet BaFe relatively ₁₂O ₁₉Absorbing property slightly be better than bar-shaped (the secondary ancient cooking vessel of Pueraria lobota, Zhu Jing, Chen Limin. aerospace material technology, 1996, (5), 42; Refreshing former straight filial piety. electronic material (Japanese), 1982, (9), 25); In addition, bar-shaped and sheet BaFe ₁₂O ₁₉Coercive force all be higher than three-dimensional closely spherical (G H. Mu, X. F. Pan, N. Chen, et al. Materials Research Bulletin 2008, (43): 1369) usually.Thereby the sheet-like barium ferrite meaning that preparation size is bigger is obvious.

The synthetic method of barium ferrite is more, and comparatively commonly used is sol-gel process, chemical coprecipitation, ion-exchange-resin process.Sol-gel process and ion-exchange-resin process be usually used in preparing the nearly three-dimensional of nanoscale or two-dimentional barium ferrite (Li Yongrui, Zu Yapei, heath forest etc. Chinese patent. 200510046690; Zhong Wei, all promising. Chinese patent. 200410013959).The introducing by EDTA such as Wang Lixi (Lixi Wang, Qitu Zhang, Journal of Alloys and Compounds, 2008,454,410) etc. have on this basis prepared the sheet-like barium ferrite that the sheet footpath can reach 1.5 μ m.Step is many but these methods all respond, and lack of homogeneity is wayward, and cost is higher relatively, is not easy to shortcomings such as suitability for industrialized production.The barium ferrite of chemical coprecipitation preparation is nearly three-dimensional irregular pattern or two-dimensional sheet, and this procedure is simple, is easy to industrialization.But conventional coprecipitation is owing to be subjected to the restriction of thermodynamical equilibrium, prolong again behind the crystal crystallization certain hour at a certain temperature crystallization time to the particle diameter growth effect less and particle radial dimension usually at nanoscale.

In sum, provide a kind of particle radius-thickness ratio and radial dimension bigger, and method is simple, cost is lower, is easy to the sheet BaFe of suitability for industrialized production ₁₂O ₁₉The preparation method, for improving BaFe ₁₂O ₁₉Performance and widen its application and have important and practical meanings.

Summary of the invention

The object of the invention provides the ferritic preparation method of a kind of two-dimensional sheet.

The technical scheme that adopts is:

The ferritic preparation method of a kind of two-dimensional sheet, its preparation process is:

(1) prepares raw material and obtain solution.Press barium salt and raw material BaFe ₁₂O ₁₉Mol ratio is that 0.01-0.6 takes by weighing barium salt and BaFe ₁₂O ₁₉By Fe (molysite)/Ba (barium salt)=11-12(mol ratio) take by weighing molysite; Press Na ₂CO ₃/ Ba(barium salt)=the 8-9(mol ratio), Na ₂CO ₃/ NaOH=3-7(mol ratio) takes by weighing Na ₂CO ₃And NaOH; With barium salt and the water-soluble mixing salt solution that is mixed with of molysite that has taken by weighing, with taking by weighing Na ₂CO ₃With the water-soluble mixed ammonium/alkali solutions that is mixed with of NaOH;

(2) preparation precursor.The BaFe that step (1) is taken by weighing ₁₂O ₁₉Put into reactor; In reactor, add mixing salt solution, under the continuous stirring mixed ammonium/alkali solutions is added reactor with certain speed and (perhaps, press H ₂O/ BaFe ₁₂O ₁₉=10-30ml/g adds water in reactor, under the continuous stirring condition, mixing salt solution and mixed ammonium/alkali solutions is added reactor simultaneously by certain speed, and control pH value is 7-9); Then the product that obtains was left standstill 10-40 hour; To the product suction filtration after leaving standstill, be washed to filtrate pH and detect nearly neutrality, obtain presoma in 10-80 ℃ of drying again;

(3) preparation product.Presoma was calcined 1-7 hour down in 900-1100 ℃.Calcining grind after finishing end product.

Advantage of the present invention and characteristics are mainly: at first, can prepare particle diameter by the technology of the present invention and can reach micron-sized sheet-like barium ferrite BaFe ₁₂O ₁₉Secondly, can be to sheet BaFe by changing reaction condition ₁₂O ₁₉Particle size carry out modulation; The 3rd, with the be regulated to basis of reaction condition to particle size, can be to the BaFe of sheet ₁₂O ₁₉Magnetostatic performance or electromagnetic performance regulate; The 4th, raw material BaFe ₁₂O ₁₉It is unrestricted to originate.That is to say, can BaFe any method preparation, any particle size ₁₂O ₁₉Be raw material, prepare sheet BaFe through the technology of the present invention ₁₂O ₁₉The 5th, the method process stabilizing is easy to repetition, and cost is lower, and properties of product are stable.

Description of drawings

Fig. 1 embodiment 1 raw material BaFe ₁₂O ₁₉(a) SEM figure.

Fig. 2 embodiment 1 product B aFe ₁₂O ₁₉(b) SEM figure.

Fig. 3 embodiment 1 raw material BaFe ₁₂O ₁₉(a) and product B aFe ₁₂O ₁₉(b) XRD figure.

Fig. 4 embodiment 1 raw material BaFe ₁₂O ₁₉(a) and product B aFe ₁₂O ₁₉(b) VSM figure.

The SEM figure of Fig. 5 embodiment 2 products.

Fig. 6 embodiment 3 raw material BaFe ₁₂O ₁₉(a) SEM figure.

Fig. 7 embodiment 3 product B aFe ₁₂O ₁₉(b) SEM figure.

Embodiment

Embodiment 1

Press the described chemical coprecipitation of document (S.R. Janasi, M. Emura, F.J.G. Landgraf, et al .Journal of Magnetism and Magnetic Materials, 2002,238,168) and prepare BaFe ₁₂O ₁₉And be raw material with it, press BaCl ₂2H ₂O and raw material BaFe ₁₂O ₁₉Mol ratio is 0.3 to take by weighing BaCl ₂2H ₂O presses FeCl ₃6H ₂O and BaCl ₂2H ₂The O mol ratio is 11.1 to take by weighing FeCl ₃6H ₂O is with BaCl ₂2H ₂O and raw material BaFe ₁₂O ₁₉And FeCl ₃6H ₂O is water-soluble join Ba ²⁺Concentration is 0.005mol/l mixing salt solution A; Press Na ₂CO ₃/ BaCl ₂2H ₂The O mol ratio is 8.5 to take by weighing Na ₂CO ₃, and press NaOH/NaCO ₃Mol ratio is 5 to take by weighing NaOH, with NaOH and NaCO ₃Water-soluble join CO ₃ ^2-Concentration is 0.01mol/l mixed ammonium/alkali solutions B.Conditioned reaction actuator temperature to 60 ℃ is with solution A and BaFe ₁₂O ₁₉Place reactor and continuous stirring, solution B is pressed adding speed and raw material BaFe ₁₂O ₁₉Ratio range be that the product with gained leaves standstill 24h then in the adding reactor of 160-240ml/h/g.To the suction filtration repeatedly of the product after leaving standstill, be washed to filtrate and approach neutral.Filter cake is obtained precursor at 60 ℃ of dry 24h.Presoma was calcined 4.5 hours in 1000 ℃.Calcining grind after finishing end product BaFe ₁₂O ₁₉

Accompanying drawing 1 is raw material BaFe ₁₂O ₁₉With the SEM figure of product, accompanying drawing 2 is raw material and product X RD figure, and their explanations are BaFe with the raw material of chemical coprecipitation preparation ₁₂O ₁₉, but wherein contain a spot of Fe ₂O ₃The product that with the coprecipitation is feedstock production is pure BaFe ₁₂O ₁₉, its grain diameter is brought up to the m into 0.3-1.8 μ by the 200-600nm of raw material, and radius-thickness ratio is 5-12.Accompanying drawing 3 is VSM figure of raw material and product, and they illustrate product B aFe ₁₂O ₁₉Coercive force (Hc) bring up to 3544Oe by 2913 Oe of raw material, its saturation magnetization (Ms) slightly drops to 54emu/g for 60 emu/g by raw material.

It is higher that the present embodiment explanation can be prepared the crystallization order degree with method provided by the invention, is hexagonal plate or the nearly hexagonal BaFe of exemplary two dimensional ₁₂O ₁₉, and the increase of sheet-like particle radial dimension and radius-thickness ratio can make its magnetostatic performance obviously improve.

Embodiment 2

Step by embodiment 1 prepares BaFe ₁₂O ₁₉, the differential responses condition is: press BaCl ₂2H ₂O and raw material BaFe ₁₂O ₁₉Mol ratio is 0.1, Fe/Ba=12(mol ratio), the presoma calcination time is 3h.

Accompanying drawing 4 is the SEM figure of end-product, and it shows end-product BaFe ₁₂O ₁₉The two-dimensional sheet pattern is obvious, and grain diameter is 0.3-1.5 μ m, and radius-thickness ratio is 6-10, analyzes through VSM, and its Hc is 3632Oe, and Ms is 59emu/g.

Compare with embodiment 1, the present embodiment explanation can be to BaFe by the modulation reaction condition ₁₂O ₁₉Particle size and radius-thickness ratio regulate, thereby also can regulate its magnetostatic performance.

Embodiment 3

(2008,454: 410) described sol-gel process prepares BaFe for Lixi Wang, Qitu Zhang. Journal of Alloys and Compounds to press document ₁₂O ₁₉And be raw material with it, prepare BaFe by the step of embodiment 1 ₁₂O ₁₉

Accompanying drawing 5 is the SEM figure of raw material and product, and it shows end-product BaFe ₁₂O ₁₉Pattern in the form of sheets, grain diameter is 0.4-1.7 μ m, radius-thickness ratio is 2-9.Analyze its Hc through VSM and can reach 4586Oe, Ms is 60emu/g.

Compare with embodiment 1, the present embodiment explanation is with the BaFe of distinct methods preparation ₁₂O ₁₉Be raw material, all can prepare the BaFe that is obvious sheet pattern with the technology of the present invention ₁₂O ₁₉In addition, also can be to product B aFe by changing raw material ₁₂O ₁₉Particle size and magnetostatic performance regulate.

Claims

1. ferritic preparation method of two-dimensional sheet, its feature comprises following processing step:

1) prepares raw material and obtain solution, take by weighing barium salt and molysite and the water-soluble mixing salt solution that is mixed with, take by weighing Na ₂CO ₃With NaOH and the water-soluble mixed ammonium/alkali solutions that is mixed with, take by weighing a certain amount of raw material BaFe again ₁₂O ₁₉2) preparation presoma; The BaFe that step 1) is taken by weighing ₁₂O ₁₉Put into reactor; In reactor, add mixing salt solution, under the continuous stirring mixed ammonium/alkali solutions is added reactor with certain speed, perhaps press H ₂O/ BaFe ₁₂O ₁₉=10-30ml/g adds water in reactor, under the continuous stirring condition, mixing salt solution and mixed ammonium/alkali solutions is added reactor simultaneously by certain speed, and control pH value is 7-9; Then the product that obtains was left standstill 10-40 hour; To the product suction filtration after leaving standstill, be washed to filtrate pH and detect nearly neutrality, obtain presoma in 10-80 ℃ of drying again; 3) preparation product, with presoma in 900-1100 ℃ of down calcining 1-7 hour, grind after calcining finishes end product;

Alleged raw material BaFe in the described step 1) ₁₂O ₁₉With the proportioning of various salt be: be 11-12, Na with molar ratio computing molysite/barium salt ₂CO ₃/ barium salt is 8-9, Na ₂CO ₃/ NaOH is 3-7, barium salt/raw material BaFe ₁₂O ₁₉Be 0.01-0.6, Ba in the mixing salt solution ²⁺Concentration is 0.001-0.03 mol/l, CO in the mixed ammonium/alkali solutions ₃ ^2-Concentration is 0.001-0.03 mol/l, its step 2) in mixed ammonium/alkali solutions or mixing salt solution add reactor speed and add raw material BaFe with institute ₁₂O ₁₉Ratio range be 20-500ml/h/g;

Prepared BaFe ₁₂O ₁₉Its particle is tangible two-dimentional hexagonal or nearly hexagonal plate pattern, and the particle radial dimension reaches micron order; The particle radius-thickness ratio is greater than 5.

2. the ferritic preparation method of a kind of two-dimensional sheet as claimed in claim 1, it is characterized in that: the barium salt in the step (1) is barium chloride, barium nitrate or other soluble barium salt, molysite is iron chloride, ferric nitrate or other soluble ferric iron salt.

3. the ferritic preparation method of a kind of two-dimensional sheet as claimed in claim 1 is characterized in that: used BaFe in step (1) and (2) ₁₂O ₁₉It is that chemical coprecipitation, sol-gel process, hydro thermal method, organic resin method are prepared for raw material, and its particle size is unrestricted, and granule-morphology is the irregular three-D pattern.