PREPARATION AND APPLICATION OF A LOW-B HIGH-RESISTANCE HIGH-TEMPERATURE THERMISTOR MATERIAL WITH WIDE TEMPERATURE RANGE

Abstract

An object of the present disclosure is to provide the preparation and application of a low-B high-resistance high-temperature thermistor material with wide temperature range. The thermistor material uses CaCO.sub.3, Y.sub.2O.sub.3, Nb.sub.2O.sub.5, CeO.sub.2 and MoO.sub.3 as raw materials. The Ca.sub.1-yY.sub.yMoO.sub.4-xCeNbO.sub.4 (1≤x≤3, 0.01≤y≤0.2) high-temperature thermistor material having low-B high-resistance and wide temperature region is obtained by mixing grinding, calcination, cold isostatic pressing, high-temperature sintering and coating electrode. The material constant B.sub.200° C./600° C. is 1800 K-4000 K, and the resistivity at 25° C. is 8.0×10.sup.5 Ω.Math.cm-6.0×10.sup.7 Ω.Math.cm. The low-B high-resistance wide temperature range high-temperature thermistor material prepared by the disclosure has stable performance and good consistency. The thermistor material has obvious negative temperature coefficient characteristics in the range of 25° C.-1000° C. and is suitable for manufacturing wide temperature range high-temperature thermistor.

Claims

1. A low-B high-resistance wide temperature range high-temperature thermistor material, wherein the thermistor material is prepared by CaCO.sub.3, Nb.sub.2O.sub.5, CeO.sub.2, MoO.sub.3 and Y.sub.2O.sub.3, and the thermistor material is a composite oxide including Ca, Y, Mo, Ce and Nb.

2. The low-B high-resistance wide temperature range high-temperature thermistor material according to claim 1, wherein the chemical composition system is composed of Ca.sub.1-yY.sub.yMoO.sub.4-xCeNbO.sub.4, wherein 1≤x≤3, 0.01≤y≤0.2.

3. The low-B high-resistance wide temperature range high-temperature thermistor material according to claim 1, wherein the molar ratio of Ca, Y, Mo, Ce and Nb is (0.8˜0.99):(0.01˜0.2): 1:(1˜3):(1˜3).

4. The low-B high-resistance wide temperature range high-temperature thermistor material according to claim 1, wherein the molar ratio of Ca, Y, Mo, Ce and Nb is (0.85˜0.95):(0.05˜0.15):1:(1.5˜2.5):(1.5˜2.5).

5. A preparation method of the low-B high-resistance wide temperature range high-temperature thermistor material according to claim 1, comprising the following steps: step a, weigh CaCO.sub.3, Nb.sub.2O.sub.5, CeO.sub.2, MoO.sub.3 and Y.sub.2O.sub.3, respectively and mix them, and grind the mixed raw materials for 5-10 hours to obtain powder A; step b, calcine the powder A in step a at 1000° C.-1100° C. for 3-5 hours, and grind for 5-10 hours to obtain powder B; step c, the powder B obtained in step b is pressed into a disk, and the formed disk is cold isostatic pressed and sintered at high temperature to obtain a high-temperature thermistor ceramic; and step d, the material sintered in step c is coated with platinum paste electrode on both sides, the thickness of the electrode is 2-3 mm, and then annealed to obtain the low-B high-resistance wide temperature range high-temperature thermistor.

6. The preparation method of the low-B high-resistance type high-temperature thermistor material with wide temperature range according to claim 5, wherein in step c, the powder B is pressed to form a disk at a pressure of 10-20 Kg/cm.sup.2 for 0.5-2 minutes, the formed disk is held at a pressure of 300-400 Mpa for 1-3 minutes for cold isostatic pressing, and then sintered at a temperature of 1200-1400° C. for 6-10 hours for preparation high-temperature thermistor ceramics.

7. The preparation method of the low-B high-resistance wide temperature range high-temperature thermistor material according to claim 5, wherein the annealing in step d is at 900° C. for 30 minutes.

8. The preparation method of the low-B high-resistance wide temperature range high-temperature thermistor material according to claim 5, wherein the prepared low-B high-resistance material is a wide temperature range high-temperature thermistor material with a temperature range of 25° C.-1000° C., a material constant of B.sub.200° C./600° C.=1800 K-4000 K, and a resistivity at 25° C. of 8.0×10.sup.5 Ω.Math.cm-6.0×10.sup.7 Ω.Math.cm.

9. A preparation method of the low-B high-resistance wide temperature range high-temperature thermistor material according to claim 2, comprising the following steps: step a, weigh CaCO.sub.3, Nb.sub.2O.sub.5, CeO.sub.2, MoO.sub.3 and Y.sub.2O.sub.3, respectively and mix them, and grind the mixed raw materials for 5-10 hours to obtain powder A; step b, calcine the powder A in step a at 1000° C.-1100° C. for 3-5 hours, and grind for 5-10 hours to obtain powder B; step c, the powder B obtained in step b is pressed into a disk, and the formed disk is cold isostatic pressed and sintered at high temperature to obtain a high-temperature thermistor ceramic; and step d, the material sintered in step c is coated with platinum paste electrode on both sides, the thickness of the electrode is 2-3 mm, and then annealed to obtain the low-B high-resistance wide temperature range high-temperature thermistor.

10. A preparation method of the low-B high-resistance wide temperature range high-temperature thermistor material according to claim 3, comprising the following steps: step a, weigh CaCO.sub.3, Nb.sub.2O.sub.5, CeO.sub.2, MoO.sub.3 and Y.sub.2O.sub.3, respectively and mix them, and grind the mixed raw materials for 5-10 hours to obtain powder A; step b, calcine the powder A in step a at 1000° C.-1100° C. for 3-5 hours, and grind for 5-10 hours to obtain powder B; step c, the powder B obtained in step b is pressed into a disk, and the formed disk is cold isostatic pressed and sintered at high temperature to obtain a high-temperature thermistor ceramic; and step d, the material sintered in step c is coated with platinum paste electrode on both sides, the thickness of the electrode is 2-3 mm, and then annealed to obtain the low-B high-resistance wide temperature range high-temperature thermistor.

11. A preparation method of the low-B high-resistance wide temperature range high-temperature thermistor material according to claim 4, comprising the following steps: step a, weigh CaCO.sub.3, Nb.sub.2O.sub.5, CeO.sub.2, MoO.sub.3 and Y.sub.2O.sub.3, respectively and mix them, and grind the mixed raw materials for 5-10 hours to obtain powder A; step b, calcine the powder A in step a at 1000° C.-1100° C. for 3-5 hours, and grind for 5-10 hours to obtain powder B; step c, the powder B obtained in step b is pressed into a disk, and the formed disk is cold isostatic pressed and sintered at high temperature to obtain a high-temperature thermistor ceramic; and step d, the material sintered in step c is coated with platinum paste electrode on both sides, the thickness of the electrode is 2-3 mm, and then annealed to obtain the low-B high-resistance wide temperature range high-temperature thermistor.

12. An application of the thermistor material according to claim 1 is in manufacturing wide temperature range high-temperature thermistor.

13. An application of the thermistor material according to claim 2 is in manufacturing wide temperature range high-temperature thermistor.

14. An application of the thermistor material according to claim 3 is in manufacturing wide temperature range high-temperature thermistor.

15. An application of the thermistor material according to claim 4 is in manufacturing wide temperature range high-temperature thermistor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 is the XRD pattern of the thermistor ceramic material of the disclosure.

DESCRIPTION OF THE EMBODIMENTS

[0026] The technical scheme of the disclosure will be described in detail below, but the protection scope of the disclosure is not limited to the embodiment.

Example 1

[0027] step a, according to the composition of Ca.sub.0.8Y.sub.0.2MoO.sub.4-3CeNbO.sub.4, the analytical pure CaCO.sub.3, Nb.sub.2O.sub.5, CeO.sub.2, MoO.sub.3 and Y.sub.2O.sub.3 are respectively weighed and mixed. The mixed raw materials are ground in the agate mortar for 8 hours to obtain the powder;

[0028] step b, calcine the ground powder in step a at 1100° C. for 3 hours, and grind it for 6 hours to obtain Ca.sub.0.8Y.sub.0.2MoO.sub.4-3CeNbO.sub.4 powder;

[0029] step c, the powder obtained in step b is pressed into a disk at a pressure of 20 Kg/cm.sup.2 for 1 minute, and the disk is cold isostatic pressed for 3 minutes at a pressure of 300 Mpa, and then sintered at 1350° C. for 9 hours to produce a high temperature thermistor ceramic material. The phase structure is shown in FIG. 1, which is a composite structure, that is, CaMoO.sub.4 phase and CeNbO.sub.4 phase;

[0030] step d, the ceramic material sintered in step c is coated with platinum paste electrode on both sides, the thickness of the electrode was 2 mm, and then annealed at 900° C. for 30 minutes. The temperature range of the thermistor material is 25° C.-1000° C., the material constant B.sub.200° C./600° C. is 1800 K, and the resistivity at 25° C. is 8.0×10.sup.5 Ω.Math.cm.

Example 2

[0031] step a, According to the composition of Ca.sub.0.9Y.sub.0.1MoO.sub.4-2CeNbO.sub.4, the analytical pure CaCO.sub.3, Nb.sub.2O.sub.5, CeO.sub.2, MoO.sub.3 and Y.sub.2O.sub.3 are respectively weighed and mixed. The mixed raw materials are ground in the agate mortar for 5 hours to obtain the powder;

[0032] step b, Calcine the ground powder in step a at 1000° C. for 4 hours, and grind it for 10 hours to obtain Ca.sub.0.9Y.sub.0.1MoO.sub.4-2CeNbO.sub.4 powder;

[0033] step c, The powder obtained in step b is pressed into a disk at a pressure of 15 Kg/cm.sup.2 for 0.5 minute, and the disk is cold isostatic pressed for 1 minutes at a pressure of 350 Mpa, and then sintered at 1400° C. for 6 hours to produce a high temperature thermistor ceramic material;

[0034] step d, The ceramic material sintered in step c is coated with platinum paste electrode on both sides, the thickness of the electrode was 2 mm, and then annealed at 900° C. for 30 minutes. The temperature range of the thermistor material is 25° C.-1000° C., the material constant B.sub.200° C./600° C. is 2000 K, the resistivity at 25° C. is 3.0×10.sup.6 Ω.Math.cm.

Example 3

[0035] step a, According to the composition of Ca.sub.0.99Y.sub.0.01MoO.sub.4-1CeNbO.sub.4, the analytical pure CaCO.sub.3, Nb.sub.2O.sub.5, CeO.sub.2, MoO.sub.3 and Y.sub.2O.sub.3 are respectively weighed and mixed. The mixed raw materials are ground in the agate mortar for 10 hours to obtain the powder;

[0036] step b, Calcine the ground powder in step a at 1050° C. for 5 hours, and grind it for 5 hours to obtain Ca.sub.0.99Y.sub.0.01MoO.sub.4-1CeNbO.sub.4 powder;

[0037] step c, The powder obtained in step b is pressed into a disk at a pressure of 10 Kg/cm.sup.2 for 2 minute, and the disk is cold isostatic pressed for 2 minutes at a pressure of 400 Mpa, and then sintered at 1400° C. for 10 hours to produce a high temperature thermistor ceramic material;

[0038] step d, The ceramic material sintered in step c is coated with platinum paste electrode on both sides, the thickness of the electrode was 3 mm, and then annealed at 900° C. for 30 minutes. The temperature range of the thermistor material is 25° C.-1000° C., the material constant B.sub.200° C./600° C. is 4000 K, the resistivity at 25° C. is 6.0×10.sup.7 Ω.Math.cm.

Example 4

[0039] step a, According to the composition of Ca.sub.0.85Y.sub.0.15MoO.sub.4-2CeNbO.sub.4, the analytical pure CaCO.sub.3, Nb.sub.2O.sub.5, CeO.sub.2, MoO.sub.3 and Y.sub.2O.sub.3 are respectively weighed and mixed. The mixed raw materials are ground in the agate mortar for 6 hours to obtain the powder;

[0040] step b, Calcine the ground powder in step a at 1080° C. for 5 hours, and grind it for 8 hours to obtain Ca.sub.0.85Y.sub.0.15MoO.sub.4-2CeNbO.sub.4 powder;

[0041] step c, The powder B obtained in step b is pressed into a disk at a pressure of 10 Kg/cm.sup.2 for 2 minute, and the disk is cold isostatic pressed for 3 minutes at a pressure of 300 Mpa, and then sintered at 1250° C. for 10 hours to produce a high temperature thermistor ceramic material;

[0042] step d, The ceramic material sintered in step c is coated with platinum paste electrode on both sides, the thickness of the electrode is 2 mm, and then annealed at 900° C. for 30 minutes. The temperature range is 25° C.-1000° C., the material constant B.sub.200° C./600° C. is 1900 K, the resistivity at 25° C. is 1.5×10.sup.6 Ω.Math.cm.

Example 5

[0043] The preparation method of example 5 is the same as that of example 1, and the difference is that the composition of example 5 is Ca.sub.0.85Y.sub.0.15MoO.sub.4-1.5CeNbO.sub.4.

Example 6

[0044] The preparation method of example 6 is the same as that of example 1, and the difference is that composition of example 6 is composed of Ca.sub.0.95Y.sub.0.5MoO.sub.4-2.5CeNbO.sub.4.

[0045] The performance parameters of the low-B high-resistance wide temperature range high-temperature thermistor material prepared in examples 5-6 are all in the following range: the temperature range is 25° C.-1000° C., the material constant B.sub.200° C./600° C. is 1800 K-4000 K, the resistivity at 25° C. is 8.0×10.sup.5 Ω.Math.cm-6.0×10.sup.7 Ω.Math.cm.

[0046] It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure covers modifications and variations provided that they fall within the scope of the following claims and their equivalents.