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A W-type ferrite electromagnetic-wave absorbent and the corresponding preparation method

An electromagnetic wave absorbing and ferrite technology, applied in chemical instruments and methods, electrical components, other chemical processes, etc., can solve the problems of time-consuming processes, limited mass production of materials, and complexity, and achieve thin coatings and easy processing. and mass production, the effect of wide bandwidth

Active Publication Date: 2008-07-09
溧阳常大技术转移中心有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Patent CN 1807537A adopts the in-situ deposition method to prepare composite absorbing materials, which is time-consuming and the production process is complicated, which greatly limits the mass production of materials

Method used

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  • A W-type ferrite electromagnetic-wave absorbent and the corresponding preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Step 1: Add Ba(NO 3 ) 2 , Co(NO 3 ) 2 ·6H 2 O and Fe(NO 3 ) 3 ·9H 2 O was dissolved in distilled water and stirred to obtain a clear and transparent solution. The molar ratio of raw materials: Ba / Co / Fe=1:2:16.

[0029] Step 2: Add citric acid to the solution of step (1) and stir to obtain a clear and transparent solution. The molar ratio of raw materials: citric acid / Ba=19:1.

[0030] Step 3: Add ethylene glycol to the solution of step (2) and stir to obtain a uniform solution. The molar ratio of raw materials: ethylene glycol / citric acid = 1:1.

[0031] Step 4: Add ammonia to the solution prepared in step (3), mix it completely, and adjust the solution to neutral, pH=7.

[0032] Step 5: Place the solution of step (4) in a water bath at 90°C to evaporate slowly for 2 hours, and then dry it in an oven at 130°C until a black dry gel is formed.

[0033] Step 6: Pre-burn the dry gel at 450°C for 3 hours to completely decompose the organic matter.

[0034] Step 7: Put the pre-fi...

Embodiment 2

[0037] Step 1: Add Ba(NO 3 ) 2 , Co(NO 3 ) 2 ·6H 2 O and Fe(NO 3 ) 3 ·9H 2 O was dissolved in distilled water and stirred to obtain a clear and transparent solution. Raw material molar ratio: Ba / Co / Fe=1:2:15.2.

[0038] Step 2 to Step 6: Same as Step 2 to Step 6 in Example 1.

[0039] Step 7: Put the pre-fired sample in a muffle furnace, heat up to 1800°C at a rate of 5°C / min, keep it for 5 hours, and cool down with the furnace to obtain a single W-type ferrite crystal phase.

[0040] Figure 2 is a SEM photograph of the prepared ferrite. The prepared sample has a particle size of 1 to 5 microns and a uniform distribution.

Embodiment 3

[0042] Step 1: Add Ba(NO 3 ) 2 , Co(NO 3 ) 2 ·6H 2 O, Ni(NO 3 ) 2 ·6H 2 O and Fe(NO 3 ) 3 ·9H 2 O was dissolved in distilled water and stirred to obtain a clear and transparent solution. The molar ratio of raw materials: Ba / Co / Ni / Fe=1:1:1:16.

[0043] Step 2 to Step 6: Same as Step 2 to Step 6 in Example 1.

[0044] Step 7: Place the pre-fired sample in a muffle furnace, heat up to 1000°C at a rate of 5°C / min, keep it for 3 hours, and cool down with the furnace to obtain ferrite with a particle size of 1-10 microns. It is a single W shape.

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Abstract

The invention discloses a W-typed ferrite electromagnetic absorbing material and the preparation method thereof, which takes barium, cobalt, the iron nitrate of iron, organic acid, saturated lower alcohol and water as main raw materials with the molar ratio that Ba / Fe is equal to 1:14-17, Ba / Co is equal to 1:1-2, the organic acid / Ba is equal to 10-40:1 and the saturated lower alcohol / organic acid is equal to 0-3:1; the raw material can be mixed by transition metal elements such as lanthanum, nickel, titanium, manganese, copper and cerium; the invention is prepared by a sol-gel process and roasting under pre-roasting and high temperature conditions; the invention takes the organic acid as a complexing agent and takes the saturated small molecular alcohol as a dispersant; the invention has the advantages of uniform and complete crystallization, excellent electromagnetic performance, high dielectric constant, high absorbing efficiency, thin coating, wide frequency band, etc. The invention is easy for processing and batch production and is an ideal method for preparing the ferrite.

Description

Technical field [0001] The invention relates to an electromagnetic wave absorbing material and a preparation process thereof, in particular to a W-shaped ferrite electromagnetic wave absorbing material and a preparation method thereof. Background technique [0002] Among the magnetic dielectric absorbing materials, the hexagonal ferrite is superior to the spinel ferrite, and the W-type of the hexagonal ferrite has better absorption characteristics than other types. The molecular formula of W type ferrite is BaMe 2 Fe 16 O 27 (Me is a divalent metal ion). It has the characteristics of low price, high resistance, stable chemical properties and various excellent magnetic properties. It has been widely used as permanent magnet materials and high-density perpendicular magnetic recording media. Especially in recent years, with the development of stealth technology and electromagnetic shielding technology, ferrite has developed rapidly due to its good absorption characteristics. [0003...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05K9/00C09K3/00
Inventor 张跃严生虎刘建武沈介发马锦国
Owner 溧阳常大技术转移中心有限公司
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