阅读说明：本技术 一种锡酸盐体系负温度系数热敏电阻材料及其制备方法 (Stannate system negative temperature coefficient thermistor material and preparation method thereof ) 是由 高博 李晓卉 常爱民 于 2021-02-25 设计创作，主要内容包括：本发明涉及一种锡酸盐体系负温度系数热敏电阻材料,该体系热敏电阻材料是以二氧化锡、三氧化二镧、三氧化二钕、三氧化二钐和三氧化二钆为原料,将二氧化锡分别与三氧化二镧、三氧化二钕、三氧化二钐或三氧化二钆混合,经过球磨、干燥、研磨、煅烧、再研磨、冷等静压成型、高温烧结,即可得到锡酸盐体系材料,该体系材料电性能参数为：B-(400℃/1000℃)=12320-15177K,ρ-(1000℃)=0.650-8.095×10～3Ω·cm。本发明制备的锡酸盐负温度系数热敏电阻材料体系在温度区间400℃-1100℃内具有明显的负温度系数特性,该材料体系电性能稳定,一致性好,老化性能稳定,对氧分压不敏感,是一类适合制造用于高温及不同氧分压环境的热敏电阻材料。(The invention relates to a stannate system negative temperature coefficient thermistor material, which takes tin dioxide, lanthanum oxide, neodymium oxide, samarium oxide and gadolinium oxide as raw materials, the tin dioxide is respectively mixed with the lanthanum oxide, the neodymium oxide, the samarium oxide or the gadolinium oxide, and the stannate system material can be obtained after ball milling, drying, grinding, calcining, regrinding, cold isostatic pressing and high-temperature sintering, and the electrical performance parameters of the system material are as follows: b is 400℃/1000℃ =12320‑15177K，ρ 1000℃ =0.650‑8.095×10 3 Omega cm. The stannate negative temperature coefficient thermistor material system prepared by the invention has obvious negative temperature coefficient characteristics within a temperature range of 400-1100 ℃, has stable electrical property, good consistency, stable aging performance and insensitivity to oxygen partial pressure, and is suitable for manufacturing thermistor materials used in high-temperature and different oxygen partial pressure environments.)

1. Negative temperature of stannate systemThe coefficient thermistor material is characterized in that the chemical general formula of the thermistor material is as follows: a. the₂Sn₂O₇Wherein A = La, Nd, Sm or Gd, is formed by mixing and burning raw material tin dioxide with lanthanum oxide, neodymium oxide, samarium oxide or gadolinium oxide respectively, and the specific operation is carried out according to the following steps:

a. according to A₂Sn₂O₇Weighing tin dioxide, mixing the tin dioxide with lanthanum oxide, neodymium oxide, samarium oxide or gadolinium oxide respectively, placing the mixture in an agate ball milling tank, wet-milling the mixture for 6 to 8 hours by using analytically pure absolute ethyl alcohol as a dispersion medium, drying the slurry after the wet milling at the temperature of 120 ℃, taking out the slurry and milling the slurry for 1 hour to obtain powder;

b. calcining the powder obtained in the step a at the temperature of 1200-1250 ℃ for 3-5h, and then grinding for 2-4h to obtain thermistor powder;

c. c, mixing the powder obtained in the step b at a ratio of 15-25kg/cm²The pressure is pressed and molded, the pressure maintaining time is 1-2min, the molded block is subjected to cold isostatic pressing, the pressure is maintained at 250-300MPa for 1-3min, and then the block is sintered for 10h at the temperature of 1600-1650 ℃ to obtain the negative temperature coefficient thermistor material of the stannate system;

d. coating platinum slurry electrodes on the front and back surfaces of the negative temperature coefficient thermistor material of the stannate system obtained in the step c, and then annealing at 900 ℃ for 1-2h to obtain the negative temperature coefficient thermistor material with the following electrical performance parameters: b is_{400℃/1000℃}=12320-15177K，ρ_1000℃=0.650-8.095×10³Omega cm stannate system negative temperature coefficient thermistor material.

2. A method for preparing a stannate system negative temperature coefficient thermistor material is characterized by comprising the following steps:

a. according to A₂Sn₂O₇Weighing tin dioxide, mixing with lanthanum oxide, neodymium oxide, samarium oxide or gadolinium oxide, placing in an agate ball milling tank, wet milling for 6-8h with analytically pure absolute ethyl alcohol as a dispersion medium, drying the slurry after wet milling at 120 ℃, taking the slurry, and drying the slurryGrinding for 1h to obtain powder;

b. calcining the powder obtained in the step a at the temperature of 1200-1250 ℃ for 3-5h, and then grinding for 2-4h to obtain thermistor powder;

c. c, mixing the powder obtained in the step b at a ratio of 15-25kg/cm²The pressure is pressed and molded, the pressure maintaining time is 1-2min, the molded block is subjected to cold isostatic pressing, the pressure is maintained at 250-300MPa for 1-3min, and then the block is sintered for 10h at the temperature of 1600-1650 ℃ to obtain the negative temperature coefficient thermistor material of the stannate system;

d. coating platinum slurry electrodes on the front and back surfaces of the negative temperature coefficient thermistor material of the stannate system obtained in the step c, and then annealing at 900 ℃ for 1-2h to obtain the negative temperature coefficient thermistor material with the following electrical performance parameters: b is_{400℃/1000℃}=12320-15177K，ρ_1000℃=0.650-8.095×10³Omega cm stannate system negative temperature coefficient thermistor material.

Technical Field

The invention relates to a stannate system negative temperature coefficient thermistor material and a preparation method thereof, the thermistor material has obvious negative temperature coefficient characteristic in the temperature range of 400-1100 ℃, is a novel thermistor suitable for manufacturing a high-temperature thermistor, and belongs to the field of semiconductor sensors.

Background

With the rapid development of scientific and technical information technology, automotive electronics and aerospace industry, there is an increasing demand for negative temperature coefficient thermistors (NTCs) having high accuracy and being applicable to high-temperature and severe environments. In recent years, perovskite-based composite materials and spinel-based composite materials are used as hot materials of high-temperature NTC thermistor materials. Although great progress has been made, the maximum temperature upper limit for most reported materials is only 800 ℃ and a few materials reach 1000 ℃. Meanwhile, most NTC thermistor materials have a resistance of only tens of ohms at a high temperature upper limit, and the resistance change range is small, so that the practical application of the NTC thermistor materials in a high-temperature environment is limited. And the materials also have the defects of poor aging characteristics, susceptibility to oxygen environment influence on electrical properties and the like. In the face of high temperature environments and high pressures and severe oxidation or corrosion caused by high temperatures, such materials are required to have high chemical and thermal stability and to be insensitive to oxygen partial pressure. Currently, most high temperature NTC thermistor materials cannot meet such requirements.

Therefore, the invention discloses a stannate system negative temperature coefficient thermistor material, which has obvious negative temperature coefficient characteristics within the temperature of 400-1100 ℃, stable electrical property, good consistency, stable aging performance and insensitivity to oxygen partial pressure, and is a thermistor material suitable for manufacturing a thermistor used in a high-temperature environment.

Disclosure of Invention

The invention aims to provide a stannate system negative temperature coefficient thermistor material and a preparation method thereofMixing lanthanum oxide, neodymium oxide, samarium oxide or gadolinium oxide, and performing ball milling, drying, grinding, calcining, re-grinding, cold isostatic pressing and high-temperature sintering to obtain a stannate system material, wherein the electrical performance parameters of the system material are as follows: b is_{400℃/1000℃}＝12320-15177K，ρ_1000℃＝0.650-8.095×10³Omega cm. The stannate system negative temperature coefficient thermistor material has obvious negative temperature coefficient characteristics within a temperature range of 400-1100 ℃, has stable electrical property, good consistency, stable aging performance and insensitivity to oxygen partial pressure, and is a thermistor material suitable for manufacturing thermistors in high-temperature environments.

The invention relates to a stannate system negative temperature coefficient thermistor material, wherein the chemical general formula of the system thermistor material is as follows: a. the₂Sn₂O₇Wherein A is La, Nd, Sm or Gd, which is formed by mixing and burning raw material tin dioxide with lanthanum oxide, neodymium oxide, samarium oxide or gadolinium oxide respectively, and the specific operation is carried out according to the following steps:

a. according to A₂Sn₂O₇Weighing tin dioxide, mixing the tin dioxide with lanthanum oxide, neodymium oxide, samarium oxide or gadolinium oxide respectively, placing the mixture in an agate ball milling tank, wet-milling the mixture for 6 to 8 hours by using analytically pure absolute ethyl alcohol as a dispersion medium, drying the slurry after the wet milling at the temperature of 120 ℃, taking out the slurry and milling the slurry for 1 hour to obtain powder;

b. calcining the powder obtained in the step a at the temperature of 1200-1250 ℃ for 3-5h, and then grinding for 2-4h to obtain thermistor powder;

c. c, mixing the powder obtained in the step b at a ratio of 15-25kg/cm²The pressure is pressed and molded, the pressure maintaining time is 1-2min, the molded block is subjected to cold isostatic pressing, the pressure is maintained at 250-300MPa for 1-3min, and then the block is sintered for 10h at the temperature of 1600-1650 ℃ to obtain the negative temperature coefficient thermistor material of the stannate system;

d. coating platinum slurry electrodes on the front and back surfaces of the negative temperature coefficient thermistor material of the stannate system obtained in the step c, and then annealing at 900 ℃ for 1-2 hours to obtain the negative temperature coefficient thermistor materialThe electrical property parameters were: b is_{400℃/1000℃}＝12320-15177K，ρ_1000℃＝0.650-8.095×10³Omega cm stannate system negative temperature coefficient thermistor material.

A method for preparing a stannate system negative temperature coefficient thermistor material comprises the following steps:

a. according to A₂Sn₂O₇Weighing tin dioxide, mixing the tin dioxide with lanthanum oxide, neodymium oxide, samarium oxide or gadolinium oxide respectively, placing the mixture in an agate ball milling tank, wet-milling the mixture for 6 to 8 hours by using analytically pure absolute ethyl alcohol as a dispersion medium, drying the slurry after the wet milling at the temperature of 120 ℃, taking out the slurry and milling the slurry for 1 hour to obtain powder;

b. calcining the powder obtained in the step a at the temperature of 1200-1250 ℃ for 3-5h, and then grinding for 2-4h to obtain thermistor powder;

c. c, mixing the powder obtained in the step b at a ratio of 15-25kg/cm²The pressure is pressed and molded, the pressure maintaining time is 1-2min, the molded block is subjected to cold isostatic pressing, the pressure is maintained at 250-300MPa for 1-3min, and then the block is sintered for 10h at the temperature of 1600-1650 ℃ to obtain the negative temperature coefficient thermistor material of the stannate system;

d. coating platinum slurry electrodes on the front and back surfaces of the negative temperature coefficient thermistor material of the stannate system obtained in the step c, and then annealing at 900 ℃ for 1-2h to obtain the negative temperature coefficient thermistor material with the following electrical performance parameters: b is_{400℃/1000℃}＝12320-15177K，ρ_1000℃＝0.650-8.095×10³Omega cm stannate system negative temperature coefficient thermistor material.

The invention relates to a stannate system negative temperature coefficient thermistor material and a preparation method thereof, analytically pure tin dioxide is respectively mixed with analytically pure lanthanum oxide, analytically pure neodymium oxide, analytically pure samarium oxide or analytically pure gadolinium oxide by a ball milling method, ball milling, drying, grinding, calcining and re-grinding are carried out, then the powder is formed by sheet type cold isostatic pressing, platinum slurry electrodes are coated on the front and back surfaces after high-temperature sintering to obtain the thermistor, the system thermistor material is A₂Sn₂O₇Stannate, the bodyThe series electrical property parameters are as follows: b is_{400℃/1000℃}＝12320-15177K，ρ_1000℃＝0.650-8.095×10³Omega cm. By changing the cation at the A position, a series of A can be obtained₂Sn₂O₇The high-temperature negative temperature coefficient thermistor material.

The invention relates to a stannate system negative temperature coefficient thermistor material and a preparation method thereof, and the innovation points of the material are as follows:

(1) the stannate system A of the invention₂Sn₂O₇The negative temperature coefficient thermistor material has typical NTC characteristic in a higher temperature range of 400-1100 ℃, and is stable in performance in a high-temperature environment.

(2) The resistivity of the material is hardly influenced by oxygen partial pressure, and the material can keep higher resistivity in a high-temperature environment, can reach a kiloohm level, and is beneficial to the practical application in the high-temperature environment.

The material has obvious negative temperature coefficient characteristic, and the system material has stable electrical property, good consistency, stable aging performance and insensitivity to oxygen partial pressure, and is a thermistor material suitable for manufacturing high-temperature and different oxygen partial pressure environments.

Drawings

FIG. 1 shows the present invention A₂Sn₂O₇Graph of resistivity versus temperature for (a ═ La, Nd, Sm, Gd) materials.

FIG. 2 shows the present invention A₂Sn₂O₇Graph of resistivity versus oxygen partial pressure for (a ═ La, Nd, Sm, Gd) materials.

Detailed Description

Example 1

a. According to La₂Sn₂O₇Weighing tin dioxide and lanthanum oxide, mixing, placing in an agate ball milling tank, wet milling for 8h by using analytically pure absolute ethyl alcohol as a dispersion medium, drying slurry after wet milling at the temperature of 120 ℃, taking out and grinding for 1h to obtain powder;

b. calcining the powder obtained in the step a at 1200 ℃ for 4h, and grinding for 4h to obtain thermistor powder;

c. b, mixing the powder obtained in the step b at a ratio of 25kg/cm²Pressing the block to form the block, keeping the pressure for 2min, carrying out cold isostatic pressing on the formed block, keeping the pressure for 1min at the pressure of 300MPa, and then sintering the block at the temperature of 1600 ℃ for 10h to obtain the negative temperature coefficient thermistor material of lanthanum stannate;

d. coating platinum slurry electrodes on the front and back surfaces of the negative temperature coefficient thermistor material of lanthanum stannate obtained in the step c, and then annealing at 900 ℃ for 2 hours to obtain the thermistor material with the following electrical performance parameters: b is_{400℃/1000℃}＝15177K，ρ_1000℃＝1.707×10³Omega cm lanthanum stannate negative temperature coefficient thermistor material.

Example 2

a. According to La₂Sn₂O₇Weighing tin dioxide and lanthanum oxide, mixing, placing in an agate ball milling tank, wet milling for 8h by using analytically pure absolute ethyl alcohol as a dispersion medium, drying slurry after wet milling at the temperature of 120 ℃, taking out and grinding for 1h to obtain powder;

b. calcining the powder obtained in the step a at 1250 ℃ for 5 hours, and grinding for 4 hours to obtain thermistor powder;

c. b, mixing the powder obtained in the step b at a ratio of 25kg/cm²Pressing the block to form the block, keeping the pressure for 2min, carrying out cold isostatic pressing on the formed block, keeping the pressure for 2min at the pressure of 300MPa, and then sintering the block at the temperature of 1650 ℃ for 10h to obtain the negative temperature coefficient thermistor material of lanthanum stannate;

d. coating platinum slurry electrodes on the front and back surfaces of the negative temperature coefficient thermistor material of lanthanum stannate obtained in the step c, and then annealing at 900 ℃ for 2 hours to obtain the thermistor material with the following electrical performance parameters: b is_{400℃/1000℃}＝13643K，ρ_1000℃＝0.650×10³Omega cm lanthanum stannate negative temperature coefficient thermistor material.

Example 3

a. According to La₂Sn₂O₇Weighing tin dioxide and lanthanum oxide, mixing, placing in an agate ball milling tank, wet milling for 6h by using analytically pure absolute ethyl alcohol as a dispersion medium, and wet millingDrying the slurry at the temperature of 120 ℃, taking out and grinding for 1h to obtain powder;

b. calcining the powder obtained in the step a at 1200 ℃ for 3h, and grinding for 4h to obtain thermistor powder;

c. c, mixing the powder obtained in the step b at a ratio of 20kg/cm²Pressing the block body into a block under the pressure of 2min, carrying out cold isostatic pressing on the formed block body, keeping the pressure at 250MPa for 3min, and then sintering the block body at the temperature of 1600 ℃ for 10h to obtain the negative temperature coefficient thermistor material of lanthanum stannate;

d. coating platinum slurry electrodes on the front and back surfaces of the negative temperature coefficient thermistor material of lanthanum stannate obtained in the step c, and then annealing for 1h at 900 ℃ to obtain the thermistor material with the following electrical performance parameters: b is_{400℃/1000℃}＝14982K，ρ_1000℃＝1.638×10³Omega cm lanthanum stannate negative temperature coefficient thermistor material.

Example 4

a. According to Nd₂Sn₂O₇Weighing tin dioxide and neodymium oxide, mixing, placing in an agate ball milling tank, wet milling for 7h by using analytically pure absolute ethyl alcohol as a dispersion medium, drying slurry after wet milling at the temperature of 120 ℃, taking out and grinding for 1h to obtain powder;

b. calcining the powder obtained in the step a at 1200 ℃ for 3h, and grinding for 3h to obtain thermistor powder;

c. c, mixing the powder obtained in the step b at a ratio of 15kg/cm²The pressure is pressed into blocks for molding, the pressure maintaining time is 2min, the molded blocks are subjected to cold isostatic pressing, the pressure is maintained at 300MPa for 1min, and then the blocks are sintered for 10h at the temperature of 1600 ℃ to obtain the negative temperature coefficient thermistor material of neodymium stannate;

d. coating platinum slurry electrodes on the front and back surfaces of the neodymium stannate negative temperature coefficient thermistor material obtained in the step c, and then annealing at 900 ℃ for 1h to obtain the material with the following electrical performance parameters: b is_{400℃/1000℃}＝13705K，ρ_1000℃＝8.095×10³Omega cm neodymium stannate negative temperature coefficient thermistor material.

Example 5

a. According to Nd₂Sn₂O₇Weighing tin dioxide and neodymium oxide, mixing, placing in an agate ball milling tank, wet milling for 8h by using analytically pure absolute ethyl alcohol as a dispersion medium, drying slurry after wet milling at the temperature of 120 ℃, taking out and grinding for 2h to obtain powder;

b. calcining the powder obtained in the step a at 1200 ℃ for 3h, and grinding for 4h to obtain thermistor powder;

c. c, mixing the powder obtained in the step b at a ratio of 20kg/cm²The pressure is pressed into blocks for molding, the pressure maintaining time is 1min, the molded blocks are subjected to cold isostatic pressing, the pressure is maintained at 250MPa for 2min, and then the blocks are sintered for 10h at the temperature of 1600 ℃ to obtain the negative temperature coefficient thermistor material of neodymium stannate;

d. coating platinum slurry electrodes on the front and back surfaces of the neodymium stannate negative temperature coefficient thermistor material obtained in the step c, and then annealing at 900 ℃ for 1h to obtain the material with the following electrical performance parameters: b is_{400℃/1000℃}＝13324K，ρ_1000℃＝7.895×10³Omega cm neodymium stannate negative temperature coefficient thermistor material.

Example 6

a. According to Sm₂Sn₂O₇Weighing tin dioxide and samarium sesquioxide, mixing, placing in an agate ball milling tank, wet milling for 6 hours by using analytically pure absolute ethyl alcohol as a dispersion medium, drying slurry after the wet milling at the temperature of 120 ℃, taking out and grinding for 1 hour to obtain powder;

b. calcining the powder obtained in the step a at 1250 ℃ for 5 hours, and grinding for 2 hours to obtain thermistor powder;

c. c, mixing the powder obtained in the step b at a ratio of 20kg/cm²Pressing the blocks into blocks under the pressure of 2min, performing cold isostatic pressing on the formed blocks, maintaining the pressure at 250MPa for 2min, and sintering the blocks at 1600 ℃ for 10h to obtain the samarium stannate negative temperature coefficient thermistor material;

d. coating platinum slurry electrodes on the front and back surfaces of the samarium stannate negative temperature coefficient thermistor material obtained in the step c, and annealing at 900 ℃ for 1h to obtain the electrical propertyThe energy parameters are as follows: b is_{400℃/1000℃}＝12897K，ρ_1000℃＝1.739×10³Omega cm samarium stannate negative temperature coefficient thermistor material.

Example 7

a. According to Sm₂Sn₂O₇Weighing tin dioxide and samarium sesquioxide, mixing, placing in an agate ball milling tank, wet milling for 8h by using analytically pure absolute ethyl alcohol as a dispersion medium, drying slurry after the wet milling at the temperature of 120 ℃, taking out and grinding for 1h to obtain powder;

b. calcining the powder obtained in the step a at 1200 ℃ for 3h, and grinding for 3h to obtain thermistor powder;

c. c, mixing the powder obtained in the step b at a ratio of 20kg/cm²Pressing the blocks into blocks under the pressure of 2min, carrying out cold isostatic pressing on the formed blocks, keeping the pressure at 300MPa for 3min, and then sintering the blocks at 1600 ℃ for 10h to obtain the samarium stannate negative temperature coefficient thermistor material;

d. coating platinum slurry electrodes on the front surface and the back surface of the samarium stannate negative temperature coefficient thermistor material obtained in the step c, and then annealing at 900 ℃ for 1h to obtain the thermistor material with the following electrical performance parameters: b is_{400℃/1000℃}＝12320K，ρ_1000℃＝1.654×10³Omega cm samarium stannate negative temperature coefficient thermistor material.

Example 8

a. According to Gd₂Sn₂O₇Weighing tin dioxide and gadolinium oxide, mixing, placing in an agate ball milling tank, wet milling for 6h by using analytically pure absolute ethyl alcohol as a dispersion medium, drying slurry after wet milling at the temperature of 120 ℃, taking out and grinding for 1h to obtain powder;

b. calcining the powder obtained in the step a at 1250 ℃ for 5 hours, and grinding for 3 hours to obtain thermistor powder;

c. b, mixing the powder obtained in the step b at a ratio of 25kg/cm²Pressing the mixture into a block under the pressure of 1min, performing cold isostatic pressing on the formed block, maintaining the pressure at 250MPa for 2min, and sintering the block at 1600 ℃ for 10h to obtain the negative temperature of gadolinium stannateA coefficient thermistor material;

d. coating platinum slurry electrodes on the front surface and the back surface of the gadolinium stannate negative temperature coefficient thermistor material obtained in the step c, and then annealing for 2 hours at 900 ℃ to obtain the gadolinium stannate negative temperature coefficient thermistor material with the following electrical performance parameters: b is_{400℃/1000℃}＝13604K，ρ_1000℃＝2.812×10³Omega cm gadolinium stannate negative temperature coefficient thermistor material.

Example 9

a. According to Gd₂Sn₂O₇Weighing tin dioxide and gadolinium oxide, mixing, placing in an agate ball milling tank, wet milling for 8h by using analytically pure absolute ethyl alcohol as a dispersion medium, drying slurry after wet milling at the temperature of 120 ℃, taking out and grinding for 1h to obtain powder;

b. calcining the powder obtained in the step a at 1200 ℃ for 5 hours, and grinding for 4 hours to obtain thermistor powder;

c. c, mixing the powder obtained in the step b at a ratio of 20kg/cm²Pressing the block to form the block, keeping the pressure for 1min, carrying out cold isostatic pressing on the formed block, keeping the pressure at 300MPa for 3min, and then sintering the block at 1600 ℃ for 10h to obtain the gadolinium stannate negative temperature coefficient thermistor material;

d. coating platinum slurry electrodes on the front surface and the back surface of the gadolinium stannate negative temperature coefficient thermistor material obtained in the step c, and then annealing for 2 hours at 900 ℃ to obtain the gadolinium stannate negative temperature coefficient thermistor material with the following electrical performance parameters: b is_{400℃/1000℃}＝13256K，ρ_1000℃＝2.342×10³Omega cm gadolinium stannate negative temperature coefficient thermistor material.

Example 10

Any of the negative temperature coefficient thermistor materials of stannate systems obtained in examples 1 to 9 was subjected to a cation change at the A site to obtain a pyrochlore-structured high-temperature negative temperature coefficient thermistor material. The material has the advantages of simple preparation process, good consistency, stable aging performance and insensitivity to oxygen partial pressure, and is suitable for manufacturing thermistor materials used in high-temperature and different oxygen partial pressure environments.