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High-Curie-temperature lead-free barium-titanate-base PTCR (positive temperature coefficient of resistance) ceramic material, and preparation and application thereof

A lead-free barium titanate-based, ceramic material technology, applied in the field of electronic ceramics, can solve the problems of complex process operation, difficult semiconducting, and difficult to apply to large-scale industrial production, etc., to increase Curie temperature, reduce The effect of room temperature resistivity

Inactive Publication Date: 2015-04-29
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, studies have shown that when (Bi 0.5 Na 0.5 )TiO 3 When the content exceeds 2mol%, the BaTiO prepared by the traditional solid-state reaction method 3 -(Bi 0.5 Na 0.5 )TiO 3 Ceramics are difficult to semiconduct when sintered in air
In order to obtain the PTC performance of ceramics with higher BNT content, BaTiO 3 -(Bi 0.5 Na 0.5 )TiO 3 Ceramic sintering requires a process of reduction and re-oxidation, which is complicated to operate and requires precise control, which is difficult to apply to large-scale industrial production

Method used

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  • High-Curie-temperature lead-free barium-titanate-base PTCR (positive temperature coefficient of resistance) ceramic material, and preparation and application thereof
  • High-Curie-temperature lead-free barium-titanate-base PTCR (positive temperature coefficient of resistance) ceramic material, and preparation and application thereof
  • High-Curie-temperature lead-free barium-titanate-base PTCR (positive temperature coefficient of resistance) ceramic material, and preparation and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Embodiment 1: prepare the thermistor of high Curie temperature lead-free barium titanate-based PTCR ceramic material:

[0023] (1-x-y)BaTiO 3 -xBaBiO 3 -y(Bi 0.5 Na 0.5 )TiO 3 , take x=0.001, y=0; present embodiment according to above-mentioned molar ratio batching. The specific steps are:

[0024] Step 1. BaTiO 3 The synthesis method is: the BaCO 3 with TiO 2 The ingredients are mixed according to the molar ratio of 1:1, according to the ingredients: the mass ratio of ball stone: distilled water is 1:3:4, mixed and placed in a nylon tank for wet ball milling for 6 hours, and then the abrasive is dried at a temperature of 120 ° C, dried The material is placed in a crucible, and the temperature is raised to 1050°C at a heating rate of 5°C / min, and the temperature is kept for 2h to synthesize BaTiO. 3 .

[0025] Step 2. BaBiO 3 The synthesis method is: Bi 2 o 3 with BaCO 3 According to the molar ratio of 1:2, the ingredients are mixed according to the mass r...

Embodiment 2

[0030] Embodiment 2: prepare the thermistor of high Curie temperature lead-free barium titanate-based PTCR ceramic material:

[0031] (1-x-y)BaTiO 3 -xBaBiO 3 -y(Bi 0.5 Na 0.5 )TiO 3 , take x=0.002, y=0; present embodiment according to above-mentioned molar ratio batching. The specific steps are:

[0032] Step 1. BaTiO 3 The synthesis of is the same as in Example 1;

[0033] Step 2. BaBiO 3 The synthesis of is the same as in Example 1;

[0034] Step 3, according to 0.998BaTiO 3 -0.002BaBiO 3 -0.00036MnO 2 -0.01Si 3 N 4 Formulated with MnO 2 、Si 3 N 4 and the BaTiO synthesized in steps 1 and 2 3 Powder and BaBiO 3 The powder is compounded to form a mixture. According to the mixture: ball stone: distilled water, the mass ratio is 1:3:4, mixed and placed in a nylon tank for wet ball milling for 6 hours, and then the abrasive is dried at a temperature of 120°C to obtain a dry abrasive. ;

[0035] Step 4, with embodiment 1;

[0036] Step 5. Coat both sides of t...

Embodiment 3

[0038] Embodiment 3: Preparation of lead-free barium titanate-based PTCR ceramic material thermistor with high Curie temperature:

[0039] (1-x-y)BaTiO 3 -xBaBiO 3 -y(Bi 0.5 Na 0.5 )TiO 3 , take x=0.002, y=0.002; present embodiment according to above-mentioned molar ratio batching. The specific steps are:

[0040] Step 1. BaTiO 3 The synthesis of is the same as in Example 1;

[0041] Step 2. BaBiO 3 The synthesis of is the same as in Example 1;

[0042] Step three, (Bi 0.5 Na 0.5 ) Synthesis: Bi 2 o 3 with TiO 2 According to the molar ratio of 1:4, the ingredients are mixed according to the mass ratio of ball stone: anhydrous ethanol is 1:3:4 and placed in a nylon tank for wet ball milling for 6 hours, and then the abrasive is dried at a temperature of 90°C. The drying material was placed in a crucible, and the temperature was raised to 800°C at a heating rate of 5°C / min, and the temperature was kept for 2h to synthesize (Bi 0.5 Na 0.5 )TiO 3 .

[0043] Step ...

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Abstract

The invention discloses a high-Curie-temperature lead-free barium-titanate-base PTCR (positive temperature coefficient of resistance) ceramic material which is composed of BaTiO3, BaBiO3, (Bi0.5Na0.5)TiO3, MnO2 and Si3N4. The chemical formula of the material is (1-x-y)BaTiO[3-x]BaBiO[3-y](Bi0.5Na0.5)TiO3, wherein x=0.001-0.003, and y=0-0.01. 0.00034-0.00038mol of MnO2 and 0.008-0.012mol of Si3N4 are added to prepare every 1mol of (1-x-y)BaTiO[3-x]BaBiO[3-y](Bi0.5Na0.5)TiO3. The preparation method comprises the following steps: weighing and mixing the raw materials according to the mole formula, adding water, carrying out ball milling on the mixture, drying, keeping the temperature, drying, granulating, pelleting, and sintering to obtain the PTCR thermistor. The doping of the proper amount of BaBiO3 can lower the room temperature resistivity of the BaTiO3 system, and can enhance the Curie temperature of the system. The BT-BaBiO3-BNT system can be adopted to obtain the high-Curie-temperature lead-free PTCR material with low room temperature resistivity.

Description

technical field [0001] The invention relates to an electronic ceramic, in particular to a method for preparing high Curie temperature BT-BaBiO by a solid-state reaction method 3 -The method of BNT system PTCR ceramic material. Background technique [0002] The PTCR effect is a sudden increase in the resistivity of a resistor by several orders of magnitude at a specific temperature. This effect has a very wide range of applications in various fields such as electronics, machinery, medical and health care, agriculture, and household appliances. At present, most commercial PTCR elements use doped barium titanate-based semiconducting ceramics. The PTCR effect of barium titanate-based semiconductor ceramics is that the resistance jumps suddenly with the transformation from the square phase to the cubic phase near the Curie temperature. However, we know that pure BaTiO 3 The Curie temperature is 120°C, so BaTiO 3 The application temperature of PTCR-based ceramics is limited b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/468C04B35/622
Inventor 杨德安张驰卢丽霞丁春辉翟通
Owner TIANJIN UNIV
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