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A method for preparing multiferroic composite ceramic material by magnetic field low temperature heat treatment

A technology of low-temperature heat treatment and composite ceramics, which is applied in the field of information functional materials, can solve the problems affecting the ferroelectric and ferromagnetic properties of materials, the increase of grain size, and high heat treatment temperature, so as to improve the performance of multiferroics, increase the magnetization strength, and reduce the preparation cost. low effect

Active Publication Date: 2019-12-03
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, some of these two processes require rapid quenching, high heat treatment temperature, and long time (400-880°C, 1-6h) during the strong magnetic field treatment process, and some require an additional high-temperature annealing process (650°C ~850℃)
If these processes are not properly controlled, the grain size will increase, which will affect the ferroelectric and ferromagnetic properties of the material.

Method used

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  • A method for preparing multiferroic composite ceramic material by magnetic field low temperature heat treatment
  • A method for preparing multiferroic composite ceramic material by magnetic field low temperature heat treatment
  • A method for preparing multiferroic composite ceramic material by magnetic field low temperature heat treatment

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] 1) Nano BaTiO prepared by hydrothermal or microwave hydrothermal method 3 and BaFe 12 o 19 Powder according to 0.9BaTiO 3 -0.1BaFe 12 o 19 The ratio is mixed evenly to get 0.7BaTiO 3 -0.3BaFe 12 o 19 Body sample A;

[0028] 2) Use a press to press the green body sample A into a disc shape under 150MPa;

[0029] 3) The formed wafer blank sample A was placed in a microwave sintering furnace and sintered at 1090°C for 100s to obtain 0.9BaTiO 3 -0.1BaFe 12 o 19 Composite ceramic B;

[0030]4) The composite ceramic B of gained is placed in the magnetic field sintering furnace of nitrogen atmosphere (such as figure 1 shown) for low-temperature heat treatment, nitrogen atmosphere is introduced at room temperature, and the nitrogen flow rate is 0.07m 3 / min. Control the current of the magnetic flux coil to 10.5A, raise the temperature from room temperature to 450°C at a rate of 4°C / min and hold it for 90 minutes, and obtain a composite ceramic material with excell...

Embodiment 2

[0032] 1) Nano BaTiO prepared by hydrothermal or microwave hydrothermal method 3 and BaFe 12 o 19 Powder according to 0.8BaTiO 3 -0.2BaFe 12 o 19 The ratio is mixed evenly to get 0.7BaTiO 3 -0.3BaFe 12 o 19 Body sample A;

[0033] 2) Use a press to press the green body sample A into a disc shape under 140MPa;

[0034] 3) The formed wafer blank sample A was placed in a microwave sintering furnace and sintered at 1080°C for 120s to obtain 0.8BaTiO 3 -0.2BaFe 12 o 19 Composite ceramic B;

[0035] 4) The composite ceramic B of gained is placed in the magnetic field sintering furnace of nitrogen atmosphere (such as figure 1 shown) for low-temperature heat treatment, nitrogen atmosphere is introduced at room temperature, and the nitrogen flow rate is 0.06m 3 / min. Control the current of the magnetic flux coil to 12A, raise the temperature from room temperature to 430°C at a rate of 5°C / min and hold it for 80min, and obtain a composite ceramic material with excellent mu...

Embodiment 3

[0037] 1) Nano BaTiO prepared by hydrothermal or microwave hydrothermal method 3 and BaFe 12 o 19 Powder according to 0.6BaTiO 3 -0.4BaFe 12 o 19 The ratio is mixed evenly to get 0.7BaTiO 3 -0.3BaFe 12 o 19 Body sample A;

[0038] 2) Use a press to press the green body sample A into a disc shape under 130MPa;

[0039] 3) The molded wafer blank sample A was placed in a microwave sintering furnace and sintered at 1060°C for 180s to obtain 0.6BaTiO 3 -0.4BaFe 12 o 19 Composite ceramic B;

[0040] 4) The composite ceramic B of gained is placed in the magnetic field sintering furnace of nitrogen atmosphere (such as figure 1 shown) for low-temperature heat treatment, nitrogen atmosphere is introduced at room temperature, and the nitrogen flow rate is 0.04m 3 / min. Control the current of the magnetic flux coil to 14A, raise the temperature from room temperature to 400°C at a rate of 7°C / min and hold it for 60 minutes, and obtain a composite ceramic material with excelle...

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Abstract

The invention provides a method for preparing multi-ferrous composite ceramic material by low-temperature magnetic field heat treatment. According to the method, BaTiO3-BaFe12O19 composite ceramic is subjected to heat treatment by an external magnetic field, so that the multiferroic performance of the composite ceramic is improved. The method comprises the steps as follows: preparing nanoBaTiO3 and BaFe12O19 powder with a hydrothermal method or a microwave hydrothermal method, preparing a BaTiO3-BaFe12O19 blank sample A from nanoBaTiO3 and the BaFe12O19 powder in a ratio of (1-x):x by uniform mixing; sintering the blank sample A in a microwave sintering furnace to obtain BaTiO3-BaFe12O19 composite ceramic B after cooling with the furnace; putting the obtained composite ceramic B in a magnetic field sintering furnace in a nitrogen atmosphere for low-temperature heat treatment at a magnetic flux current of 10-14 A and a temperature of 400-450 DEG C, and preserving heat for 60-90 minutes to obtain the composite ceramic material with excellent multiferroic performance. The method has the advantages that the maximum magnetization strength of the material is increased by about 80% and the maximum polarization strength is improved by about 11% with the addition of a low-temperature magnetic field heat treatment process during preparation of ceramic, , and the method is low in preparation cost, easy to operate, environment-friendly and pollution-free in process and does not require rapid quenching after magnetic field heat treatment.

Description

Technical field: [0001] The invention belongs to the technical field of information functional materials, and in particular relates to a method for preparing multiferroic composite ceramic materials by low-temperature heat treatment in a magnetic field. Background technique: [0002] Multiferroic materials (multiferroics) refer to the basic properties of two or more types of iron in the material. The basic properties of these irons include ferroelectricity (antiferroelectricity), ferromagnetism (antiferromagnetism, ferrimagnetism) and iron elasticity. In practice, since ferroelectric polarization requires empty 3d orbitals, while ferromagnetism requires nearly filled 3d electron orbitals, it is very difficult to have both ferroelectricity and ferromagnetism in one material. In order to obtain multiferroic materials with excellent properties, the synthesis of multiferroic composites is an effective method. Multiferroic composite materials have multiple properties such as fe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/468C04B35/622C04B35/64
CPCC04B35/468C04B35/622C04B35/64C04B2235/3215C04B2235/3272C04B2235/96
Inventor 蒲永平董子靖
Owner SHAANXI UNIV OF SCI & TECH