Mo < 6 + >-doped negative temperature coefficient high-entropy thermistor material as well as preparation method and application thereof

Abstract

The invention discloses a Mo < 6 + >-doped negative temperature coefficient high-entropy thermistor material as well as a preparation method and application thereof. The thermistor material is prepared from the following raw materials: calcium carbonate, lanthanum trioxide, cerium dioxide, europium oxide, gadolinium oxide, niobium pentoxide and molybdenum trioxide; the negative temperature coefficient high-entropy thermistor material with the chemical composition of (Ca < 0.2 > La < 0.2 > Ce < 0.2 > Eu < 0.2 > Gd < 0.2 >) Nb < 1-x > Mo < x > O < 4 > is prepared by adopting a two-step sintering method, wherein x is greater than or equal to 0 and less than or equal to 0.4. The thermistor material has the entropy stabilization effect of high-entropy ceramic, and the temperature-resistance response linearity, the resistivity, the material constant and the high-temperature service stability of the material can be remarkably improved by combining the synergistic effect of heterovalent doping of heterovalent Mo < 6 + > ions. The material prepared by the method can stably work in a wide temperature range of-50 DEG C to 1250 DEG C and is good in consistency, namely, the obtained material constant is B-50 DEG C / 1250 DEG C = 4976K-6773K, the resistivity is 33.1-78.4 omega.cm at the temperature of 1250 DEG C, the linear fitting decision coefficients (COD) of ln rho and 1000 / T are both greater than or equal to 99.26%, and the material is suitable for manufacturing high-temperature thermistors.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of thermistor material preparation, and relates to a Mo 6+ Doped negative temperature coefficient high-entropy thermistor material, preparation method and application thereof. BACKGROUND

[0002] Various advanced industrial applications require high-sensitivity and high-stability temperature sensors to ensure reliable operation of equipment within different temperature ranges. In particular, in the fields of aerospace, automotive industry and energy, high-temperature negative temperature coefficient (NTC) thermistor materials capable of stable operation within a wide temperature range show great application potential. However, traditional NTC thermistor materials are prone to changes in crystal structure at high temperatures, resulting in changes in resistance characteristics and affecting the accuracy of temperature measurement. In addition, long-term exposure to extreme temperatures can accelerate the aging process of the material, leading to gradual degradation of its performance over time. These problems limit the application of traditional thermistors in high-tech fields such as aerospace, deep-sea exploration and high-end manufacturing.

[0003] Recent studies have shown that high-entropy materials, by occupying equivalent lattice sites with multiple elements, benefit from entropy-dominated phase stability, lattice distortion caused by atomic disorder, slow diffusion dynamics and the synergistic effect of multiple components, and exhibit excellent thermal and chemical stability in extreme high-temperature environments. However, the disadvantage is that strong disorder may lead to a large number of electron scattering, resulting in extremely low carrier mobility, thus limiting the improvement of electrical transport performance. In addition, this strong disorder may cause an irreconcilable performance bottleneck in high-temperature sensor applications, making it difficult to achieve high-precision response to temperature changes.

[0004] To solve the above problems, researchers mainly use the following two strategies to achieve low aging rate and high temperature measurement accuracy within a wide temperature range. First, to find new high-thermal-stability wide-temperature-range thermistor materials. Rare earth RENbO4 materials with brownmillerite structure (space group C2 / c) have attracted widespread attention as high-temperature thermistor materials due to their unique NbO x network charge conduction mechanism and the shrinkage effect of lanthanide ions. Second, by introducing defects through heterovalent doping to adjust the electronic structure of the material, reducing carrier scattering to improve carrier mobility, and this method can also enhance the thermodynamic stability of the material in high-temperature environments, allowing it to maintain excellent performance within a wider temperature range. SUMMARY

[0005] The purpose of the present application is to provide a Mo 6+The application discloses a doped negative temperature coefficient high-entropy thermistor material, a preparation method and application thereof. -50℃ / 1250℃ The material has a material constant B = 4976K-6773K, and a resistivity of 33.1-78.4 6+ Ω.cm, and a linear fitting coefficient of determination (COD) of lnρ and 1000 / T is greater than or equal to 99.907 % %. The application discloses a doped negative temperature coefficient high-entropy thermistor material.

[0006] The application discloses a Mo 6+ The doped negative temperature coefficient high-entropy thermistor material is prepared from calcium carbonate, lanthanum trioxide, cerium dioxide, europium trioxide, gadolinium trioxide, niobium pentoxide and molybdenum trioxide as raw materials. 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4, wherein 0≤x≤0.4, and the material has a monoclinic brownianite structure. a. according to the chemical composition (Ca 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4, 0≤x≤0.4, calcium carbonate, lanthanum trioxide, cerium dioxide, europium trioxide, gadolinium trioxide, niobium pentoxide and molybdenum trioxide are respectively taken as raw materials and placed in a agate ball mill jar, agate balls and anhydrous ethanol are added as grinding medium, a rotating speed is set to 300r / min, a forward rotation and reverse rotation interval time is 5 minutes, and ball milling time is 6-10 hours, so that a mixed powder is obtained. b. Calcine the mixed powder obtained in step a in air at 900-1100℃ for 3-5 hours, then place it in an agate ball mill jar for secondary grinding. Add agate grinding balls and anhydrous ethanol as grinding media. Set the rotation speed to 300 r / min and operate in an alternating forward and reverse rotation mode, with a 5-minute interval between forward and reverse rotations. The ball milling time is 6-10 hours to obtain dispersed (Ca) powder. 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 calcined powder; c. The calcined powder material obtained in step b is processed at a concentration of 15-25 kg / cm³. 2 The block is formed by uniaxial pressure for 40-80 seconds. The formed block material is then subjected to cold isostatic pressing and held at a pressure of 250-350 MPa for 3-5 minutes to obtain a block of φ8×1.2mm. d. The block obtained in step c is sintered using a two-step method. The sample is heated to 1400℃ at a heating rate of 3℃ / min, then cooled to 1200–1300℃ at a cooling rate of 2℃ / min and held at that temperature for 6–10 hours. Finally, it is cooled to room temperature in the furnace to obtain (Ca). 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 negative temperature coefficient thermistor ceramic material; e. Coat both sides of the ceramic material sintered in step d with platinum paste electrodes, and then anneal it at 900℃ for 30 minutes to obtain a material with a negative temperature coefficient characteristic in the temperature range of -50℃ to 1250℃, and a material constant of B. -50℃ / 1250℃ =4976K-6773K, resistivity at 1250℃ is 33.1–78.4 High-entropy thermistor material with a negative temperature coefficient of Ω·cm.

[0007] a kind of Mo 6+ The preparation method of doped high-entropy thermistor materials with negative temperature coefficients is carried out according to the following steps: a. According to its chemical composition (Ca) 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo xO4, 0≤x≤0.4 Calcium carbonate, lanthanum trioxide, cerium dioxide, europium trioxide, gadolinium trioxide, niobium pentoxide and molybdenum trioxide were weighed as raw materials and placed in an agate ball mill jar. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300 r / min, and the milling was carried out in a forward and reverse alternating mode with an interval of 5 minutes between forward and reverse rotation. The milling time was 6–10 hours to obtain a mixed powder. b. Calcine the mixed powder obtained in step a in air at 900-1100℃ for 3-5 hours, then place it in an agate ball mill jar for secondary grinding. Add agate grinding balls and anhydrous ethanol as grinding media. Set the rotation speed to 300 r / min and operate in an alternating forward and reverse rotation mode, with a 5-minute interval between forward and reverse rotations. The ball milling time is 6-10 hours to obtain dispersed (Ca) powder. 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 calcined powder; c. The calcined powder material obtained in step b is processed at a concentration of 15-25 kg / cm³. 2 The block is formed by uniaxial pressure for 40-80 seconds. The formed block material is then subjected to cold isostatic pressing and held at a pressure of 250-350 MPa for 3-5 minutes to obtain a block of φ8×1.2mm. d. The block obtained in step c is sintered using a two-step method. The sample is heated to 1400℃ at a heating rate of 3℃ / min, then cooled to 1200–1300℃ at a cooling rate of 2℃ / min and held at that temperature for 6–10 hours. Finally, it is cooled to room temperature in the furnace to obtain (Ca). 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 negative temperature coefficient thermistor ceramic material; e. Coat both sides of the ceramic material sintered in step d with platinum paste electrodes, and then anneal it at 900℃ for 30 minutes to obtain a material with a negative temperature coefficient characteristic in the temperature range of -50℃ to 1250℃, and a material constant of B. -50℃ / 1250℃ =4976K-6773K, resistivity at 1250℃ is 33.1–78.4 High-entropy thermistor material with a negative temperature coefficient of Ω·cm.

[0008] The Mo 6+Temperature monitoring and control of high-entropy doped thermistor materials with negative temperature coefficients in the fabrication of thermistors at high temperatures.

[0009] Compared with the prior art, the present invention has the following advantages: This invention proposes an entropy engineering-based synergistic heterovalent substitution strategy, which utilizes the entropy stabilization effect induced by the introduction of multi-element rare earth ions at the A-site and the Mo... 6+ The synergistic effect of heterovalent ion doping significantly increases the defect concentration, thereby optimizing the electron transport properties and lattice stability of the material. This further effectively enhances the linearity of the temperature-resistance response and high-temperature service stability. The Mo of the present invention 6+ Doped high-entropy thermistor materials with negative temperature coefficients can operate stably in a wide temperature range of -50–1250℃, which far exceeds the temperature adaptability range of traditional thermistor materials. The Mo of the present invention 6+ Doped high-entropy thermistor materials with negative temperature coefficients have high-precision temperature response characteristics. Their material constant B value is between 4976K and 6773K, and their coefficient of determination (COD) is as high as 99.9072%, which ensures high accuracy and reliability of temperature measurement. The two-step sintering method employed in this invention can effectively suppress grain coarsening while achieving complete densification of the material, significantly improving the material's high-temperature service stability. Furthermore, the second step involves a lower holding temperature, and although the holding time is longer, it is generally more energy-efficient than traditional processes that require prolonged holding at extremely high temperatures. Attached Figure Description

[0010] Figure 1 (Ca) in Embodiment 4 of the present invention 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 0.7 Mo 0.3 X-ray diffraction pattern of O4 thermistor; Figure 2 (Ca) in Embodiment 4 of the present invention 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 0.7 Mo 0.3 Scanning electron microscope image of O4 thermistor; Figure 3 (Ca) in Embodiment 4 of the present invention 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd0.2 )Nb 0.7 Mo 0.3 Resistance-temperature characteristic curve of O4 thermistor. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of the present invention clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments.

[0012] This invention provides a Mo 6+ The doped high-entropy thermistor material with a negative temperature coefficient has the chemical composition (Ca... 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4, where 0≤x≤0.4, is made from calcium carbonate, lanthanum trioxide, cerium dioxide, europium trioxide, gadolinium trioxide, niobium pentoxide, and molybdenum trioxide. Example 1

[0013] a. Based on 30g, according to the chemical composition (Ca... 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x 2.061g of calcium carbonate, 3.354g of lanthanum trioxide, 3.547g of cerium dioxide, 3.632g of europium trioxide, 3.735g of gadolinium trioxide, and 13.681g of niobium pentoxide were weighed out as raw materials and placed in an agate ball mill jar. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300r / min, and the milling was carried out in a forward and reverse alternating mode with an interval of 5 minutes between forward and reverse rotation. The milling time was 6 hours to obtain a mixed powder. b. The mixed powder obtained in step a was calcined in air at 900℃ for 3 hours, and then placed in an agate ball mill jar for secondary grinding. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300 r / min, and the milling was carried out in an alternating forward and reverse rotation mode, with an interval of 5 minutes between forward and reverse rotations. The milling time was 6 hours to obtain dispersed (Ca) powder. 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 calcined powder; c. The calcined powder material obtained in step b is processed at 15 kg / cm³.2 The block was formed by uniaxial pressure for 40 seconds. The formed block material was then subjected to cold isostatic pressing and held at a pressure of 250 MPa for 3 minutes to obtain a block of φ8×1.2mm. d. The block obtained in step c is sintered using a two-step method. The sample is heated to 1400℃ at a heating rate of 3℃ / min, then cooled to 1200℃ at a cooling rate of 2℃ / min and held at that temperature for 6 hours. Finally, it is cooled to room temperature in the furnace to obtain (Ca). 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 negative temperature coefficient thermistor ceramic material; e. Coat both sides of the ceramic material sintered in step d with platinum paste electrodes, and then anneal it at 900℃ for 30 minutes to obtain a material with a negative temperature coefficient characteristic in the temperature range of -50℃ to 1250℃, and a material constant of B. -50℃ / 1250℃ A high-entropy thermistor material with a negative temperature coefficient of 4976 K and a resistivity of 33.1 Ω·cm at a temperature of 1250 °C. Example 2

[0014] a. Based on 30g, according to (Ca 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 0.9 Mo 0.1 According to the chemical composition (x=0.1), 2.053g of calcium carbonate, 3.342g of lanthanum trioxide, 3.533g of cerium dioxide, 3.609g of europium trioxide, 3.721g of gadolinium trioxide, 12.267g of niobium pentoxide, and 1.476g of molybdenum trioxide were weighed out as raw materials and placed in an agate ball mill jar. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300r / min, and the milling was carried out in a forward and reverse rotation alternating mode with an interval of 5 minutes between forward and reverse rotations. The milling time was 7 hours to obtain a mixed powder. b. The mixed powder obtained in step a was calcined in air at 950℃ for 3.5 h, and then placed in an agate ball mill jar for secondary grinding. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300 r / min, and the milling was carried out in an alternating forward and reverse rotation mode, with an interval of 5 minutes between forward and reverse rotations. The milling time was 7 hours to obtain dispersed (Ca) powder. 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd0.2 )Nb 1-x Mo x O4 calcined powder; c. The calcined powder material obtained in step b is processed at 18 kg / cm³. 2 The block was formed by uniaxial pressure for 50 seconds. The formed block material was then subjected to cold isostatic pressing and held at a pressure of 280 MPa for 3.5 minutes to obtain a block with a diameter of φ8×1.2mm. d. The block obtained in step c is sintered using a two-step method. The sample is heated to 1400℃ at a heating rate of 3℃ / min, then cooled to 1220℃ at a cooling rate of 2℃ / min and held at that temperature for 7 hours. Finally, it is cooled to room temperature in the furnace to obtain (Ca). 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 negative temperature coefficient thermistor ceramic material; e. Coat both sides of the ceramic material sintered in step d with platinum paste electrodes, and then anneal it at 900℃ for 30 minutes to obtain a material with a negative temperature coefficient characteristic in the temperature range of -50℃ to 1250℃, and a material constant of B. -50℃ / 1250℃ A high-entropy thermistor material with a negative temperature coefficient of 5578K and a resistivity of 42.1Ω·cm at a temperature of 1250℃. Example 3

[0015] a. Based on 30g, according to (Ca 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 0.8 Mo 0.2 The chemical composition of O4, x=0.2, was determined by weighing 2.045g of calcium carbonate, 3.329g of lanthanum trioxide, 3.520g of cerium dioxide, 3.595g of europium trioxide, 3.707g of gadolinium trioxide, 10.863g of niobium pentoxide, and 12.941g of molybdenum trioxide as raw materials and placing them in an agate ball mill jar. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300r / min, and the milling was carried out in an alternating forward and reverse rotation mode, with a 5-minute interval between forward and reverse rotation. The milling time was 8 hours to obtain a mixed powder. b. The mixed powder obtained in step a was calcined in air at 1000℃ for 4 hours, and then placed in an agate ball mill jar for secondary grinding. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300 r / min, and the milling was carried out in an alternating forward and reverse rotation mode, with an interval of 5 minutes between forward and reverse rotation. The milling time was 8 hours to obtain dispersed (Ca) powder. 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 calcined powder; c. The calcined powder material obtained in step b is processed at 25 kg / cm³. 2 The block was formed by uniaxial pressure for 60 seconds. The formed block material was then subjected to cold isostatic pressing and held at a pressure of 300 MPa for 4 minutes to obtain a block of φ8×1.2mm. d. The block obtained in step c is sintered using a two-step method. The sample is heated to 1400℃ at a heating rate of 3℃ / min, then cooled to 1250℃ at a cooling rate of 2℃ / min and held at that temperature for 8 hours. Finally, it is cooled to room temperature in the furnace to obtain (Ca). 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 negative temperature coefficient thermistor ceramic material; e. Coat both sides of the ceramic material sintered in step d with platinum paste electrodes, and then anneal it at 900℃ for 30 minutes to obtain a material with a negative temperature coefficient characteristic in the temperature range of -50℃ to 1250℃, and a material constant of B. -50℃ / 1250℃ =5894K, resistivity is 52.9 at 1250℃. High-entropy thermistor material with a negative temperature coefficient of Ω·cm. Example 4

[0016] a. Based on 30g, according to (Ca 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 0.7 Mo 0.3The chemical composition of O4, x=0.3, was determined by weighing 2.037g of calcium carbonate, 3.316g of lanthanum trioxide, 3.507g of cerium dioxide, 3.582g of europium trioxide, 3.693g of gadolinium trioxide, 9.469g of niobium pentoxide, and 4.395g of molybdenum trioxide as raw materials and placing them in an agate ball mill jar. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300r / min, and the milling was carried out in an alternating forward and reverse rotation mode, with a 5-minute interval between forward and reverse rotation. The milling time was 9 hours to obtain a mixed powder. b. The mixed powder obtained in step a was calcined in air at 1050℃ for 4.5 h, and then placed in an agate ball mill jar for secondary grinding. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300 r / min, and the milling was carried out in an alternating forward and reverse rotation mode, with an interval of 5 minutes between forward and reverse rotation. The milling time was 9 hours to obtain dispersed (Ca) powder. 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 calcined powder; c. The calcined powder material obtained in step b is processed at 23 kg / cm³. 2 The block was formed by uniaxial pressure for 70 seconds. The formed block material was then subjected to cold isostatic pressing and held at a pressure of 330 MPa for 4.5 minutes to obtain a block with a diameter of φ8×1.2mm. d. The block obtained in step c is sintered using a two-step method. The sample is heated to 1400℃ at a heating rate of 3℃ / min, then cooled to 1280℃ at a cooling rate of 2℃ / min and held at that temperature for 9 hours. Finally, it is cooled to room temperature in the furnace to obtain (Ca). 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 negative temperature coefficient thermistor ceramic material; e. Coat both sides of the ceramic material sintered in step d with platinum paste electrodes, and then anneal it at 900℃ for 30 minutes to obtain a material with a negative temperature coefficient characteristic in the temperature range of -50℃ to 1250℃, and a material constant of B. -50℃ / 1250℃ =6219K, resistivity is 59.0 at 1250℃. High-entropy thermistor material with a negative temperature coefficient of Ω·cm. Example 5

[0017] a. Based on 30g, according to (Ca0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 0.6 Mo 0.4 The chemical composition of O4, x=0.4, was determined by weighing 2.030g of calcium carbonate, 3.304g of lanthanum trioxide, 3.494g of cerium dioxide, 3.569g of europium trioxide, 3.679g of gadolinium trioxide, 8.086g of niobium pentoxide, and 5.838g of molybdenum trioxide as raw materials and placing them in an agate ball mill jar. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300r / min, and the milling was carried out in an alternating forward and reverse rotation mode, with a 5-minute interval between forward and reverse rotation. The milling time was 10 hours to obtain a mixed powder. b. The mixed powder obtained in step a was calcined in air at 1100℃ for 5 hours, and then placed in an agate ball mill jar for secondary grinding. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300 r / min, and the milling was carried out in an alternating forward and reverse rotation mode, with an interval of 5 minutes between forward and reverse rotation. The milling time was 10 hours to obtain dispersed (Ca) powder. 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 calcined powder; c. The calcined powder material obtained in step b is processed at 25 kg / cm³. 2 The block was formed by uniaxial pressure for 80 seconds. The formed block material was then subjected to cold isostatic pressing and held at a pressure of 350 MPa for 5 minutes to obtain a block of φ8×1.2mm. d. The block obtained in step c is sintered using a two-step method. The sample is heated to 1400℃ at a heating rate of 3℃ / min, then cooled to 1300℃ at a cooling rate of 2℃ / min and held at that temperature for 10 hours. Finally, it is cooled to room temperature in the furnace to obtain (Ca). 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 negative temperature coefficient thermistor ceramic material; e. Coat both sides of the ceramic material sintered in step d with platinum paste electrodes, and then anneal it at 900℃ for 30 minutes to obtain a material with a negative temperature coefficient characteristic in the temperature range of -50℃ to 1250℃, and a material constant of B. -50℃ / 1250℃=6773K, resistivity is 78.4 at 1250℃. High-entropy thermistor material with a negative temperature coefficient of Ω·cm. Example 6

[0018] Taking Example 4 as an example: Figure 1 As shown, all diffraction peaks correspond to a mixed solid solution structure, which is composed of a monoclinic yttrium niobite type RENbO4 (space group C2 / c) and a tetragonal scheelite type structure (space group I41 / a). like Figure 2 As shown, it can be seen that (Ca) 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 0.7 Mo 0.3 The O4 thermistor ceramic has obvious grains and almost no obvious pores throughout the sample. This indicates that Example 3 prepared a dense ceramic body with an overall grain distribution range of 0.5-3.9 μm and an average grain size of 1.95 μm, which conforms to a normal distribution. like Figure 3 As shown, it can be seen that (Ca) 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 0.7 Mo 0.3 O4 high-entropy thermistors exhibit significant negative temperature characteristics, with a linear fit COD of 99.907 for lnρ and 1000 / T in the range of -50–1250℃.

[0019] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A kind of Mo 6+ The doped high-entropy thermistor material with negative temperature coefficient is characterized by... This thermistor material uses calcium carbonate, lanthanum trioxide, cerium dioxide, europium trioxide, gadolinium trioxide, niobium pentoxide, and molybdenum trioxide as raw materials, and its chemical composition is (Ca... 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4, where 0 ≤ x ≤ 0.4, is a monoclinic yttrium-niobium mineral structure. The specific operation is carried out according to the following steps: a. According to its chemical composition (Ca) 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4, 0≤x≤0.4 Calcium carbonate, lanthanum trioxide, cerium dioxide, europium trioxide, gadolinium trioxide, niobium pentoxide and molybdenum trioxide were weighed as raw materials and placed in an agate ball mill jar. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300 r / min, and the milling was carried out in a forward and reverse alternating mode with an interval of 5 minutes between forward and reverse rotation. The milling time was 6–10 hours to obtain a mixed powder. b. Calcine the mixed powder obtained in step a in air at 900-1100℃ for 3-5 hours, then place it in an agate ball mill jar for secondary grinding. Add agate grinding balls and anhydrous ethanol as grinding media. Set the rotation speed to 300 r / min and operate in an alternating forward and reverse rotation mode, with a 5-minute interval between forward and reverse rotations. The ball milling time is 6-10 hours to obtain dispersed (Ca) powder. 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 calcined powder; c. The calcined powder material obtained in step b is processed at a concentration of 15-25 kg / cm³. 2 The block is formed by uniaxial pressure for 40-80 seconds. The formed block material is then subjected to cold isostatic pressing and held at a pressure of 250-350 MPa for 3-5 minutes to obtain a block of φ8×1.2mm. d. The block obtained in step c is sintered using a two-step method. The sample is heated to 1400℃ at a heating rate of 3℃ / min, then cooled to 1200–1300℃ at a cooling rate of 2℃ / min and held at that temperature for 6–10 hours. Finally, it is cooled to room temperature in the furnace to obtain (Ca). 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 negative temperature coefficient thermistor ceramic material; e. Coat both sides of the ceramic material sintered in step d with platinum paste electrodes, and then anneal it at 900℃ for 30 minutes to obtain a material with a negative temperature coefficient characteristic in the temperature range of -50℃ to 1250℃, and a material constant of B. -50℃ / 1250℃ =4976K-6773K, resistivity of 33.1–78.4Ω·cm at 1250℃.

2. A kind of Mo 6+ A method for preparing doped high-entropy thermistor materials with negative temperature coefficients, characterized in that, The specific operation is carried out according to the following steps: a. According to its chemical composition (Ca) 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4, 0≤x≤0.4 Calcium carbonate, lanthanum trioxide, cerium dioxide, europium trioxide, gadolinium trioxide, niobium pentoxide and molybdenum trioxide were weighed as raw materials and placed in an agate ball mill jar. Agate grinding balls and anhydrous ethanol were added as grinding media. The rotation speed was set to 300 r / min, and the milling was carried out in a forward and reverse alternating mode with an interval of 5 minutes between forward and reverse rotation. The milling time was 6–10 hours to obtain a mixed powder. b. Calcine the mixed powder obtained in step a in air at 900-1100℃ for 3-5 hours, then place it in an agate ball mill jar for secondary grinding. Add agate grinding balls and anhydrous ethanol as grinding media. Set the rotation speed to 300 r / min and operate in an alternating forward and reverse rotation mode, with a 5-minute interval between forward and reverse rotations. The ball milling time is 6-10 hours to obtain dispersed (Ca) powder. 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 calcined powder; c. The calcined powder material obtained in step b is processed at a concentration of 15-25 kg / cm³. 2 The block is formed by uniaxial pressure for 40-80 seconds. The formed block material is then subjected to cold isostatic pressing and held at a pressure of 250-350 MPa for 3-5 minutes to obtain a block of φ8×1.2mm. d. The block obtained in step c is sintered using a two-step method. The sample is heated to 1400℃ at a heating rate of 3℃ / min, then cooled to 1200–1300℃ at a cooling rate of 2℃ / min and held at that temperature for 6–10 hours. Finally, it is cooled to room temperature in the furnace to obtain (Ca). 0.2 La 0.2 Ce 0.2 Eu 0.2 Gd 0.2 )Nb 1-x Mo x O4 negative temperature coefficient thermistor ceramic material; e. Coat both sides of the ceramic material sintered in step d with platinum paste electrodes, and then anneal it at 900℃ for 30 minutes to obtain a material with a negative temperature coefficient characteristic in the temperature range of -50℃ to 1250℃, and a material constant of B. -50℃ / 1250℃ =4976K-6773K, resistivity of 33.1–78.4Ω·cm at 1250℃.

3. The Mo according to claim 1 or 2 6+ Application of doped high-entropy thermistor materials with negative temperature coefficients in the fabrication of thermistors for high-temperature environmental temperature monitoring and control.

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