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Negative temperature coefficient two-phase composite thermistor composition and preparation thereof

A technology of negative temperature coefficient and heat-sensitive material, applied in the field of negative temperature coefficient dual-phase composite heat-sensitive sensor material and its preparation, can solve the problems of difficult high resistivity, low resistivity, unfavorable material stability, low resistivity, etc. The effect of improved mechanical strength, good matching and good thermal stability

Inactive Publication Date: 2008-12-24
HEFEI SENSING ELECTRONICS +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] According to the report of China's "Semiconductor Ceramics and Applications" (133-134, 1991), heat treatment can be used to adjust the NTC resistivity and B value, but this method also changes the B value while changing the resistivity, and involves High temperature quenching process is not conducive to the stability of the material
Another common way to adjust the resistivity and B value is to change the element content in the system or dope new elements. The essence of this method is to change the resistance value by changing the activation energy of the spinel system. The B value also changes greatly during the process of the rate, so it is easy to prepare NTC materials with "high resistivity and high B value or low resistivity and low B value", but it is difficult to use this method to prepare "high resistance NTC material with low B value"

Method used

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  • Negative temperature coefficient two-phase composite thermistor composition and preparation thereof
  • Negative temperature coefficient two-phase composite thermistor composition and preparation thereof
  • Negative temperature coefficient two-phase composite thermistor composition and preparation thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Embodiment 1: (Fe 1.0 Cu 0.4 Ni 1.32 mn 3.28 o 8 )(YSZ) 1.5 preparation and testing of

[0014] Fe used in this example 1.0 Cu 0.4 Ni 1.32 mn 3.28 o 4 The powder is obtained by calcining the compound oxalate produced by solid-phase reaction at room temperature: the molar ratio of analytically pure copper acetate, iron oxalate, manganese acetate, nickel acetate, and oxalic acid is 0.4:1:3.28:1.32: 7.2. Use an analytical balance to weigh the above-mentioned substances of corresponding quality, mix the above-mentioned substances with zirconia balls in ethanol and ball mill for 1 day. The milling time should not be too short. Insufficient ball milling will lead to poor powder consistency. Lengthening can make the particle size of the powder smaller. In the present invention, powders with medium particle size are selected, and the ball milling time is generally selected to be 1 to 2 days. The ball milling time used in this example was 1 day; the obtained composit...

Embodiment 2

[0023] Embodiment 2: (Fe 1.0 Cu 0.4 Ni 1.32 mn 3.28 o 8 )(YSZ) 4 preparation and testing of

[0024] This example adopts the same preparation method as Example 1, the difference is that: the single-phase powder calcining condition is 850°C for 4h; the dual-phase powder ratio Fe 1.0 Cu 0.4 Ni 1.32 mn 3.28 o 8 :YSZ is 1:4, the ball milling time is 2 days, and the sintering temperature of the composite powder is increased to 1250°C, the particle size of the powder prepared under this condition is slightly smaller, 50-60 μm.

[0025] The same method as in Example 1 is used to carry out X-ray and scanning electron microscope tests on the sintered dual-phase composite material in this example. The results show that the single-phase powder obtained in this example is a spinel phase with a cubic structure; The phase composite material is composed of a cubic structure spinel phase and a cubic structure YSZ phase. The cubic spinel phase with a small mole fraction is evenly dis...

Embodiment 3

[0028] Embodiment 3: (Fe 1.0 Cu 0.3 Ni 1.32 mn 3.38 o 8 )(YSZ) 1.5 preparation and testing of

[0029] This example adopts the same preparation method as Example 1, the difference is that: the calcination condition of the single-phase powder is 800°C for 2h; the molar ratio of the two-phase powder is changed to Fe 1.0 Cu 0.3 Ni 1.32 mn 3.38 o 8 :YSZ is 1:1.5.

[0030] The same method as in Example 1 is used to carry out X-ray and scanning electron microscope tests on the sintered dual-phase composite material in this example. The results show that the single-phase powder in this example is a spinel phase with a cubic structure; the dual-phase composite The material is composed of a cubic structure spinel phase and a cubic structure YSZ phase. The cubic spinel phase with a small mole fraction is evenly distributed in the cubic phase YSZ with a large mole fraction, and forms a percolation network. The crystal of the spinel phase The particle size is 1-2 μm.

[0031] ...

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Abstract

The invention discloses a negative temperature coefficient two-phase composite heat-sensitive material and a method for preparing the same characterized by mixing and milling the copper acetate, ferric oxalate, manganese acetate, nickel acetate and oxalate according to the mol ratio of 0.2-0.6: 1: 3.48-3.08: 1.32: 7.2, calcining the mixture after drying, mixing the prepared powder with partial stable cubic zirconia powder according to the mol ratio of 1: 1.5-4, getting two-phase composite powder after milling and drying, getting the negative temperature coefficient material with a relative density more than 94% after sintering. The material has a stable structure, a sintering temperature between 1200 and 1250 DEG C, a higher mechanical strength than the single-phase spinel ceramic, a B value less than 2800K, a resistivity of 1000omega.cm, a resistance drift less than 3% when accelerated ageing 1000 hours at 150 DEG C, a very good NTC property between -60 DEG C to +50 DEG C, and is suitable for the negative temperature coefficient heat sensitive sensor material in the modern aerostat.

Description

technical field [0001] The invention belongs to the technical field of negative temperature coefficient heat-sensitive materials, in particular to a class of negative temperature coefficient (NTC) dual-phase composite heat-sensitive sensor materials used in modern high-altitude balloons and a preparation method thereof. Background technique [0002] Spinel structure compound is a commonly used NTC material, in view of the resistivity of this type of material has an Arrhenius (Arrhenius) relationship with respect to temperature: R=R 0 exp(B / T), where R 0 It is the conductivity (Ω·cm) of the material whose temperature tends to infinity, B is the thermal constant (K), and T is the absolute temperature (K), so this material can be used as a negative coefficient thermistor. Most of the existing negative temperature coefficient thermistors are made of spinel semiconductor ceramics, so as to use Mn-Cu-Ni-O series, Mn-Co-Ni-O series or Mn-Fe-Ni-O series The Mn-containing spinel st...

Claims

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Application Information

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IPC IPC(8): C04B35/48C04B35/622
Inventor 罗伟杨萍华朱运兵陈初升刘原平
Owner HEFEI SENSING ELECTRONICS
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