High-entropy perovskite type high-temperature thermistor material and preparation method thereof

Abstract

The invention provides a high-entropy perovskite type high-temperature thermistor material and a preparation method thereof.The material is prepared from calcium carbonate, barium carbonate, strontium carbonate, magnesium oxide, europium oxide, sodium carbonate, copper oxide and titanium dioxide through mixing, grinding, calcining, cold isostatic pressing, high-temperature sintering and electrode coating and burning. The material constant is B150 DEG C / 850 DEG C = 6207 K-9496 K, the resistivity at the temperature of 150 DEG C is 9.6 * 10 < 5 > omega.cm to 8.4 * 10 < 7 > omega.cm, and the sensitivity coefficient at the temperature of 850 DEG C is-0.49% / K to-0.75% / K. The invention also discloses a preparation method of the high-entropy perovskite type high-temperature thermistor material. The thermistor material prepared by the method is stable in performance, good in consistency, good in resistance-temperature curve linearity and large in sensitivity coefficient at high temperature, has obvious negative temperature coefficient characteristics in the range of 150-850 DEG C, and is suitable for manufacturing high-temperature thermistors.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor process technologies, and particularly relates to a high-entropy perovskite-like high-temperature thermistor material based on the high-entropy concept and a preparation method thereof. Background Art

[0002] With the rapid development of electronic information technology, the research on new negative temperature coefficient thermistor (NTCR) materials has always been the focus of many scientific research workers. NTCR materials are widely used in fields such as temperature detection, control, and compensation, including multiple industries such as household appliances, medical devices, aerospace, and automotive manufacturing. People expect to develop more sensitive, stable, and high-temperature-resistant NTCR materials to meet the ever-changing technical requirements. At the same time, with the continuous emergence of emerging industries, the demand for temperature control and sensing technologies is also increasing continuously, which further promotes the research and application of NTCR materials. Therefore, carrying out research on high-temperature thermistor materials with new structures is of great significance for enriching the thermistor material system.

[0003] CaCu3Ti4O 12 The material is a material with a body-centered cubic perovskite-like structure, and its space group is Im-3. The liquid-phase sintering mechanism makes the ceramic have high density, so it has high thermal stability. However, when the temperature of this material reaches 300 °C, the resistance-temperature curve will undergo a non-linear transformation, resulting in its inability to be applied in the high-temperature region. This non-linear transformation is caused by the change of the grain conduction type from impurity scattering dominance to phonon and lattice scattering dominance at 300 °C. Therefore, it is particularly important to study and improve the preparation process and structural design of CaCu3Ti4O 12 materials to improve their high-temperature stability and application performance.

[0004] Based on the non-linear characteristics of the resistance-temperature curve of CaCu3Ti4O 12 materials at 300 °C, the present invention adopts a high-entropy strategy to perform high-entropy design on its Ca site to prepare a high-entropy perovskite-like (CaBaSrM1M2) 0.2 Cu3Ti4O 12 high-temperature thermistor material in the temperature range of 150 - 850 °C. In addition, by designing donor elements, acceptor elements, and the coexistence of donor and acceptor elements in the material, the material constants of the ceramic are adjusted to make it suitable for various environments. Summary of the Invention

[0005] The object of the present invention is to provide a high-entropy perovskite-type high-temperature thermistor material and a preparation method thereof. The material uses calcium carbonate, barium carbonate, strontium carbonate, magnesium oxide, europium sesquioxide, sodium carbonate, copper oxide, and titanium dioxide as raw materials. Through mixing and grinding, calcination, cold isostatic pressing, high-temperature sintering, and electrode coating, a high-entropy perovskite-type high-temperature thermistor material can be obtained, and the material constant is B 150℃ / 850℃ = 6207K - 9496K, and the resistivity at a temperature of 150 °C is 9.6×10 5 Ω·cm - 8.4×10 7 Ω·cm, and the sensitivity coefficient at a temperature of 850 °C is -0.49% / K - -0.75% / K for the high-temperature thermistor material. The thermistor material prepared by the present invention has stable performance, good consistency, and a high linearity of the resistance-temperature curve. The thermistor material has an obvious negative temperature coefficient characteristic in the range of 150 °C - 850 °C and is suitable for manufacturing high-temperature thermistors.

[0006] A high-entropy perovskite-type high-temperature thermistor material described in the present invention uses calcium carbonate, barium carbonate, strontium carbonate, magnesium oxide, europium sesquioxide, sodium carbonate, copper oxide, and titanium dioxide as raw materials, and its chemical composition system is (CaBaSrM1M2) 0.2 Cu3Ti4O 12 , belonging to the body-centered cubic perovskite structure, with the space group Im-3, where M1, M2 = Mg, Eu, Na. The specific operation is carried out according to the following steps:

[0007] a. According to (CaBaSrM1M2) 0.2 Cu3Ti4O 12 where M1, M2 = Mg, Eu, Na, respectively weigh calcium carbonate, barium carbonate, strontium carbonate, magnesium oxide, europium sesquioxide, sodium carbonate, copper oxide, and titanium dioxide for mixing, and place them in an agate mortar for grinding for 6 - 10 hours to obtain a powder;

[0008] b. Calcinate the powder ground in step a at a temperature of 850 - 950 °C for 4 - 8 hours, and then grind it for 5 - 8 hours to obtain (CaBaSrM1M2) 0.2 Cu3Ti4O 12 M1, M2 = Mg, Eu, Na powder;

[0009] c. Press the powder material obtained in step b into a block at a pressure of 10 - 20 Kg / cm 2 for 0.5 - 2 minutes. Cold isostatic press the formed block material, keep the pressure at 250 - 350 MPa for 1 - 3 minutes, and then sinter it at a temperature of 950 °C - 1050 °C for 4 - 8 hours to obtain a high-temperature thermistor ceramic material;

[0010] d. Coat platinum paste electrodes on both the front and back sides of the ceramic material sintered in step c, and then anneal at 900 °C for 30 minutes to obtain a high-temperature thermistor material with a negative temperature coefficient characteristic in the temperature range of 150 °C - 850 °C, a material constant B 150℃ / 850℃ = 6207K - 9496K, the resistivity at 150 °C is 9.6×10 5 Ω·cm - 8.4×10 7 Ω·cm, and the sensitivity coefficient at 850 °C is -0.49% / K - -0.75% / K.

[0011] A preparation method of a high-entropy perovskite-type high-temperature thermistor material is carried out according to the following steps:

[0012] a. According to (CaBaSrM1M2) 0.2 Cu3Ti4O 12 where M1, M2 = Mg, Eu, Na, respectively weigh calcium carbonate, barium carbonate, strontium carbonate, magnesium oxide, europium sesquioxide, sodium carbonate, copper oxide and titanium dioxide for mixing, and place them in an agate mortar for grinding for 6 - 10 hours to obtain a powder;

[0013] b. Calcinate the ground powder in step a at 850 - 950 °C for 4 - 8 hours, and then grind for 5 - 8 hours to obtain (CaBaSrM1M2) 0.2 Cu3Ti4O 12 M1, M2 = Mg, Eu, Na powder;

[0014] c. Press the powder material obtained in step b into a block at a pressure of 10 - 20 Kg / cm 2 for 0.5 - 2 minutes, perform cold isostatic pressing on the formed block material, keep the pressure at 250 - 350 MPa for 1 - 3 minutes, and then sinter at 950 °C - 1050 °C for 4 - 8 hours to obtain a high-temperature thermistor ceramic material;

[0015] d. Coat platinum paste electrodes on both the front and back sides of the ceramic material sintered in step c, and then anneal at 900 °C for 30 minutes to obtain a high-temperature thermistor material with a negative temperature coefficient characteristic in the temperature range of 150 °C - 850 °C, a material constant B 150℃ / 850℃ = 6207K - 9496K, the resistivity at 150 °C is 9.6×10 5 Ω·cm - 8.4×10 7 Ω·cm, and the sensitivity coefficient at 850 °C is -0.49% / K - -0.75% / K.

[0016] A high-entropy perovskite-like high-temperature thermistor material and a preparation method thereof according to the present invention. By using the solid-phase method, oxides of calcium, barium, strontium, magnesium, europium, sodium, copper and titanium are mixed, ground, calcined, mixed and ground again to obtain a negative temperature coefficient thermistor powder material. Then, the formed bulk material is cold isostatically pressed. After high-temperature sintering, platinum paste electrodes are coated on both the front and back sides to obtain a thermistor ceramic sheet. The thermistor of this ceramic sheet is a body-centered cubic perovskite-like (CaBaSrM1M2) 0.2 Cu3Ti4O 12 (M1, M2 = Mg, Eu, Na) ceramic material, and its material constant is B 150℃ / 850℃ = 6207K - 9496K, and the resistivity at a temperature of 150 °C is 9.6×10 5 Ω·cm - 8.4×10 7 Ω·cm, and the sensitivity coefficient at a temperature of 850 °C is -0.49% / K - -0.75% / K. The high-temperature thermistor material prepared by the method of the present invention has stable performance, good consistency, and high linearity of the resistance-temperature curve. This thermistor material has an obvious negative temperature coefficient characteristic in the temperature range of 150 °C - 850 °C and is suitable for manufacturing high-temperature thermistors. Brief Description of the Drawings

[0017] Figure 1 is the XRD pattern of the (CaBaSrM1M2) 0.2 Cu3Ti4O 12 (M1, M2 = Mg, Eu, Na) thermosensitive ceramic material of the present invention.

[0018] Figure 2 is the resistance-temperature curve graph of the (CaBaSrM1M2) 0.2 Cu3Ti4O 12 (M1, M2 = Mg, Eu, Na) thermosensitive ceramic material of the present invention. Detailed Embodiments

[0019] Example 1

[0020] a. First, according to the composition of (CaBaSrMgEu) 0.2 Cu3Ti4O 12 , analytical pure calcium carbonate, barium carbonate, strontium carbonate, magnesium oxide, europium sesquioxide, copper oxide and titanium dioxide are weighed and mixed respectively, and placed in an agate mortar and ground for 6 hours to obtain a powder;

[0021] b. The powder ground in step a is calcined at a temperature of 850 °C for 4 hours, and after grinding for 5 hours, the (CaBaSrMgEu) 0.2 Cu3Ti4O 12 powder is obtained;

[0022] c. Press the powder obtained in step b into a compact at a pressure of 10 Kg / cm 2 , for 0.5 minutes. Subject the formed block material to cold isostatic pressing, hold the pressure at 250 MPa for 1 minute, and then sinter it at a temperature of 950 °C for 4 hours to obtain a high-temperature thermosensitive ceramic material;

[0023] d. Coat platinum paste electrodes on both the front and back sides of the ceramic material sintered in step c, and then anneal it at 900 °C for 30 minutes to obtain a high-temperature thermistor material with a negative temperature coefficient characteristic in the temperature range of 150 - 850 °C, a material constant of B 150℃ / 850℃ = 9496 K, a resistivity of 0.6×10 5 Ω·cm at a temperature of 150 °C, and a sensitivity coefficient of -0.75% / K at a temperature of 850 °C.

[0024] Example 2

[0025] a. Weigh calcium carbonate, barium carbonate, strontium carbonate, magnesium oxide, europium sesquioxide, copper oxide, and titanium dioxide respectively according to the composition of (CaBaSrMgNa) 0.2 Cu3Ti4O 12 , mix them, and grind them in an agate mortar for 8 hours to obtain a powder;

[0026] b. Calcinate the ground powder in step a at a temperature of 900 °C for 6 hours, and then grind it for 7 hours to obtain the (CaBaSrMgNa) 0.2 Cu3Ti4O 12 powder;

[0027] c. Press the powder obtained in step b into a compact at a pressure of 15 Kg / cm 2 , for 1 minute. Subject the formed block material to cold isostatic pressing, hold the pressure at 300 MPa for 3 minutes, and then sinter it at a temperature of 1000 °C for 6 hours to obtain a high-temperature thermosensitive ceramic material;

[0028] d. Coat platinum paste electrodes on both the front and back sides of the ceramic material sintered in step c, and then anneal it at a temperature of 900 °C for 30 minutes to obtain a high-temperature thermistor material with a negative temperature coefficient characteristic in the temperature range of 150 = 850 °C, a material constant of B 150℃ / 850℃ = 8379 K, a resistivity of 2.4×10 7 Ω cm at a temperature of 150 °C, and a sensitivity coefficient of -0.66% / K at a temperature of 850 °C.

[0029] Example 3

[0030] a. Weigh calcium carbonate, barium carbonate, strontium carbonate, europium sesquioxide, sodium carbonate, copper oxide, and titanium dioxide respectively according to the composition of (CaBaSrEuNa) 0.2 Cu3Ti4O 12For the composition, weigh calcium carbonate, barium carbonate, strontium carbonate, europium sesquioxide, sodium carbonate, copper oxide and titanium dioxide respectively and mix them, then place them in an agate mortar and grind for 10 hours to obtain a powder.

[0031] b. Calcinate the ground powder in step a at a temperature of 950 °C for 8 hours, and then grind for 8 hours to obtain the (CaBaSrEuNa) 0.2 Cu3Ti4O 12 powder.

[0032] c. Press the powder material obtained in step b into a block under a pressure of 20 Kg / cm 2 for 2 minutes. Then perform cold isostatic pressing on the formed block material, keep the pressure at 350 MPa for 3 minutes, and then sinter at a temperature of 1050 °C for 8 hours to obtain a high-temperature thermosensitive ceramic material.

[0033] d. Coat platinum paste electrodes on both the front and back sides of the ceramic material sintered in step c, and then anneal at a temperature of 900 °C for 30 minutes to obtain a high-temperature thermistor material with a negative temperature coefficient characteristic in the temperature range of 150 - 850 °C, a material constant of B 150℃ / 850℃ = 6207 K, a resistivity of 3.4×10 7 Ω·cm at a temperature of 150 °C and a sensitivity coefficient of -0.49% / K at a temperature of 850 °C.

Claims

1. A high-entropy perovskite-like high-temperature thermistor material, characterized in that The material uses calcium carbonate, barium carbonate, strontium carbonate, magnesium oxide, europium sesquioxide, sodium carbonate, copper oxide and titanium dioxide as raw materials, and its chemical composition system is (CaBaSrM1M2) 0.2 Cu3Ti4O 12 , belonging to the body-centered cubic perovskite structure, with the space group Im-3, where M1, M2 = Mg, Eu, Na. The specific operation is carried out according to the following steps: a. According to (CaBaSrM1M2) 0.2 Cu3Ti4O 12 Among them, M1, M2 = Mg, Eu, Na. Weigh calcium carbonate, barium carbonate, strontium carbonate, magnesium oxide, europium sesquioxide, sodium carbonate, copper oxide and titanium dioxide respectively, mix them, and grind them in an agate mortar for 6 - 10 hours to obtain a powder. b. Calcinate the ground powder in step a at a temperature of 850 - 950 °C for 4 - 8 hours, and then grind for 5 - 8 hours to obtain (CaBaSrM1M2) 0.2 Cu3Ti4O 12 M1, M2 = Mg, Eu, Na powder c. Press the powder material obtained in step b into a block at a pressure of 10 - 20 Kg / cm 2 , and the time is 0.5 - 2 minutes. Subject the formed block material to cold isostatic pressing, hold the pressure at 250 - 350 MPa for 1 - 3 minutes, and then sinter it at a temperature of 950°C - 1050°C for 4 - 8 hours to obtain a high-temperature thermosensitive ceramic material; d. Coat the front and back sides of the ceramic material sintered in step c with platinum paste electrodes, and then anneal at 900 °C for 30 minutes to obtain a high-temperature thermistor material with a negative temperature coefficient characteristic in the temperature range of 150 °C - 850 °C, a material constant of B 150℃ / 850℃ = 6207K - 9496K, and the resistivity at 150 °C is 9.6×10 5 Ω·cm - 8.4×10 7 Ω·cm, and the sensitivity coefficient at 850 °C is -0.49 % / K - -0.75 % / K.

2. A preparation method of a high-entropy perovskite-like high-temperature thermistor material, characterized in that Proceed as follows: a. According to (CaBaSrM1M2) 0.2 Cu3Ti4O 12 where M1, M2 = Mg, Eu, Na, respectively weigh calcium carbonate, barium carbonate, strontium carbonate, magnesium oxide, europium sesquioxide, sodium carbonate, copper oxide and titanium dioxide, mix them, and grind them in an agate mortar for 6 - 10 hours to obtain a powder. b. Calcinate the ground powder in step a at a temperature of 850 - 950 °C for 4 - 8 hours, and then grind it for 5 - 8 hours to obtain (CaBaSrM1M2) 0.2 Cu3Ti4O 12 M1, M2 = Mg, Eu, Na powder c. Press the powder material obtained in step b into a compact at a pressure of 10 - 20 Kg / cm 2 , with a time of 0.5 - 2 minutes. Then, perform cold isostatic pressing on the formed block material, hold the pressure at 250 - 350 MPa for 1 - 3 minutes, and then sinter at a temperature of 950°C - 1050°C for 4 - 8 hours to obtain a high-temperature thermosensitive ceramic material; d. Coat the front and back sides of the ceramic material sintered in step c with platinum paste electrodes, and then anneal at 900 °C for 30 minutes to obtain a high-temperature thermistor material with a negative temperature coefficient characteristic in the temperature range of 150 °C - 850 °C, a material constant of B 150℃ / 850℃ = 6207K - 9496K, the resistivity at 150 °C is 9.6×10 5 Ω·cm - 8.4×10 7 Ω·cm, and the sensitivity coefficient at 850 °C is -0.49 % / K - -0.75 % / K.

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