Application of high-entropy two-dimensional material in thermometer and thermometer

Abstract

The invention provides an application of a high-entropy two-dimensional material in a thermometer, and a temperature sensing element of the thermometer is composed of a material with the following chemical formula: HEX2 + / -delta, 0 < = delta < = 0.5; wherein HE is selected from 3-15 metal elements of groups IIIB to VB in the periodic table of elements; the atom ratio of each metal element is independently 3%-60%, and the sum of the atom ratios of the metal elements is equal to 100%; and X is selected from one or more of O, S, Se and Te. The invention also provides a thermometer. According to the thermometer, a high-entropy two-dimensional material is adopted as a temperature sensing element. The use temperature range of the thermometer is very wide, for example, the thermometer can be used between 0.3 K and 420 K. In addition, the thermometer provided by the invention has the characteristics of wide temperature range, high stability, high precision and irradiation resistance.

Description

Technical Field

[0001] The present invention belongs to the field of material application. Specifically, the present invention relates to a use of a high entropy two-dimensional material in a thermometer and the thermometer. Background Art

[0002] One of the most important advances related to cryogenics is the development of cryogenic temperature measurement technology. Cryogenic temperature measurement plays an indispensable role in pharmaceutical storage, laboratory research, industrial cooling systems, practical applications of superconductors, aerospace and defense. In the past two decades, thermometers of various forms and materials have been developed, such as platinum thermometers, semiconductor thermometers such as germanium, rhodium iron thermometers, carbon glass thermometers, and diode thermometers.

[0003] These thermometers all have some significant defects. For example, platinum resistance thermometers are very stable to the use environment, but because the resistance of metals decreases rapidly at low temperatures, the sensitivity of resistance values ​​to temperature changes is also greatly reduced. Therefore, platinum thermometers are generally used for temperature detection above 13K. Semiconductor thermometers such as doped germanium have non-monotonic changes in resistance with temperature above 100K, so their use temperature is generally below 100K. Rhodium iron resistance thermometers can cover the temperature range of 0.65K to 400K, but due to the presence of magnetic elements, there is a significant magnetoresistance effect in the magnetic field, so they cannot be used for temperature detection under strong magnetic fields. Silicon and gallium arsenide diodes can cover the entire temperature range of 1.4K to 500K, but their use is limited in high magnetic fields. Carbon glass resistance thermometers can cover the temperature range of 1.4K to 325K and have good adaptability to magnetic fields, but because carbon glass is prone to crystallization and grain boundaries between amorphous particles after multiple thermal cycles, its long-term stability is significantly inferior to platinum, germanium, and rhodium iron resistance thermometers.

[0004] In many application fields, the above-mentioned thermometers cannot meet the use requirements. For example, in the high-energy field, long-term monitoring of superconducting magnets and detection of liquefaction and distribution of cryogenic refrigerants are required. Thermometers in the prior art cannot meet the monitoring and control of liquid fuels, propulsion systems and cooling equipment in aerospace, as well as the requirements for thermometer accuracy and stability of thermostats in basic scientific research. Therefore, sensors used in such applications need to have multiple properties, including a large temperature measurement range from 0.3K (or lower to dilution refrigeration temperature) to 400K, magnetic field insensitivity, radiation hardness, high resolution to detect small temperature changes, fast thermal response time to detect impending magnet quench, and good long-term stability.

[0005] In view of the lack of ideal working materials in the field of low-temperature temperature measurement, in 1989 the U.S. Department of Energy funded a three-phase research project for the development of thermometers in superconducting super colliders. This led to the birth of a ZrN-based thermometer named Cernox. Cernox can cover a temperature range of 0.1-420K depending on the brand, is less affected by magnetic fields and radiation, and has little change in resistance value after long-term use. Therefore, most of the cryostats in the world currently use Cernox as thermometers. However, the patent of Cernox is owned by Lake Shore Cryotronics, Inc. of the United States (US5367285A), and thermometers at home and abroad need to be purchased from this company. The existing Cernox thermometers are expensive and have complex preparation processes.

[0006] High entropy two-dimensional materials have been a research hotspot in recent years, mainly focusing on the study of catalytic, magnetic, optical and superconducting properties. For example, the existing paper High Entropy van der Waals Materials (Adv. Sci. 2022, 9, 2203219) discloses its applications in catalysis, magnetism and optics.

[0007] Therefore, there is an urgent need to develop a new resistance-type wide temperature range high-precision thermometer with performance comparable to that of Cernox. Summary of the invention

[0008] The purpose of the present invention is to provide a new thermometer. The thermometer uses a high entropy two-dimensional material as a temperature sensing element. The thermometer has a very wide operating temperature range, for example, it can be used between 0.3K-420K. In addition, the thermometer of the present invention has the characteristics of wide temperature range, high stability, high precision, and radiation resistance.

[0009] The above-mentioned object of the present invention is achieved through the following technical solutions.

[0010] In the context of the present invention, the term "high entropy two-dimensional material" refers to a two-dimensional material composed of three or more metal elements selected from Groups IIIB to VB of the Periodic Table.

[0011] In one aspect, the present invention provides a use of a high entropy two-dimensional material in a thermometer, wherein the temperature sensing element of the thermometer is composed of a material having the following chemical formula:

[0012] HEX 2±δ , 0≤δ≤0.5;

[0013] HE is 3-15 metal elements selected from Groups IIIB to VB of the periodic table; the atomic percentage of each metal element is independently 3%-60% and the sum of the atomic percentages of each metal element is equal to 100%;

[0014] X is one or more selected from O, S, Se and Te.

[0015] The inventors of the present invention unexpectedly found that when high-entropy two-dimensional materials are used for the temperature sensing element of the thermometer, a wide temperature range, high stability, high precision, and radiation-resistant thermometer can be prepared. Without wishing to be bound by theory, the concept of the present invention is based on the following four points: for a wide monotonic temperature measurement range, the electrical curve of the high-entropy disordered system exhibits a variable range transition behavior, thereby satisfying the requirement that it will not diverge rapidly in the low temperature zone; for the requirement of magnetic insensitivity, the high-entropy system can obtain a material system with a small magnetic resistance change by selecting suitable elements due to the diversity of its element combination; for cycle life, the high-entropy two-dimensional thin layer is a single crystal, thereby effectively reducing the changes caused by the weak links between grain boundaries and grains during repeated heating and cooling; furthermore, the high-entropy material system has better stability and high corrosion resistance than single members, and the high-entropy system also has self-healing characteristics, and has good tolerance to radiation damage, and is expected to be used in special use environments such as aerospace and large accelerator beam stations.

[0016] Preferably, in the use of the high entropy two-dimensional material in a thermometer described in the present invention, the operating temperature range of the thermometer is 0.3K-420K.

[0017] Preferably, in the use of the high entropy two-dimensional material in a thermometer described in the present invention, the temperature sensing element is composed of the material in the form of a block, a thin sheet or a film.

[0018] Preferably, in the use of the high entropy two-dimensional material in a thermometer described in the present invention, the material is a single crystal or a polycrystal.

[0019] Preferably, in the use of the high entropy two-dimensional material described in the present invention in a thermometer, the resistance value of the thermometer is 1 milliohm to 500 megohm.

[0020] In another aspect, the present invention provides a thermometer, wherein the temperature sensing element of the thermometer is composed of a material having the following chemical formula:

[0021] HEX 2±δ , 0≤δ≤0.5;

[0022] HE is 3-15 metal elements selected from Groups IIIB to VB of the periodic table; the atomic percentage of each metal element is independently 3%-60% and the sum of the atomic percentages of each metal element is equal to 100%;

[0023] X is one or more selected from O, S, Se and Te.

[0024] Preferably, in the thermometer described in the present invention, the operating temperature range of the thermometer is 0.3K-420K.

[0025] Preferably, in the thermometer described in the present invention, the temperature sensing element is composed of the material in the form of a block, a sheet or a film.

[0026] Preferably, in the thermometer described in the present invention, the material is single crystal or polycrystalline.

[0027] Preferably, in the thermometer described in the present invention, the resistance value of the thermometer is 1 milliohm to 500 megohm.

[0028] In a specific embodiment of the present invention, a bulk single crystal sample of a high entropy two-dimensional material can be obtained by a gas phase transport method: first, a selected high entropy HE element and an X element are mixed in a ratio of 1:2 (the total atomic ratio of the HE element is recorded as 1), and then a vacuum tube is sealed and fired at 600°C to 1100°C, kept warm for 1 day, and then cooled to obtain HEX 2-δ The polycrystalline sample was then HEX 2-δ The sample is sealed with a certain amount of iodine and iodine is used as a transmission medium. The two ends of the quartz tube are placed in a tube furnace at 1000-1100℃ and 800-950℃ for 1-30 days respectively. It is cooled to room temperature by quenching to obtain a bulk single crystal of a high entropy two-dimensional material.

[0029] In a specific embodiment of the present invention, a high entropy two-dimensional material thin film thermometer can be obtained by the following two ways:

[0030] One approach is to use mechanical stripping to cleave the bulk single crystal of the obtained high-entropy two-dimensional material into the ideal thickness through tape stripping and adhere it to a sapphire substrate; then, prepare the electrode by thermal evaporation coating, magnetron sputtering coating or electron beam coating; finally, obtain the required thin film thermometer by encapsulating it with an insulating layer such as boron nitride or electrical sealant.

[0031] Another approach is to directly deposit a thin film sample of a certain thickness on a sapphire substrate by chemical vapor deposition; then, prepare the electrode by thermal evaporation, magnetron sputtering or electron beam coating; finally, evaporate a silicon oxide insulating layer or encapsulate it with electrical insulating glue to obtain the desired thin film thermometer.

[0032] The present invention has the following beneficial effects:

[0033] The present invention provides a high entropy two-dimensional material HEX 2-δ A new use of the invention can be used to prepare a thermometer with wide temperature range, high stability, high precision and radiation resistance.

[0034] HEX 2-δThe resistance value changes monotonically in the temperature range of 0.3K-420K, and the resistance value is between 1 milliohm and 500 megohm. 2-δ The resistance variation range is highly adjustable with the composition, so that an optimal temperature sensitivity can be obtained. The temperature error range of the thermometer at 2K is less than 1% after 1000 thermal shocks. In addition, the magnetoresistance variation range of the sample is less than 5% under an external field of 9T, and the resistance variation at 2K is less than 2% after 10kGy of γ-ray irradiation, showing excellent radiation resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The embodiments of the present invention are described in detail below with reference to the accompanying drawings, wherein:

[0036] Figure 1 The high entropy two-dimensional material Ti of Example 1 of the present invention 0.4 V 0.15 Cr 0.15 Nb 0.15 Ta 0.15 Crystal optical photograph of Se2.

[0037] Figure 2 The high entropy two-dimensional material Ti of Example 1 of the present invention 0.4 V 0.15 Cr 0.15 Nb 0.15 Ta 0.15 Energy dispersive X-ray spectroscopy (EDX) composition analysis of Se2 shows that the ratio results are close to the nominal ratio.

[0038] Figure 3 The high entropy two-dimensional material Ti obtained by Example 1 of the present invention 0.4 V 0.15 Cr 0.15 Nb 0.15 Ta 0.15 Optical photograph of the prototype device of thin film resistor thermometer prepared by Se2.

[0039] Figure 4 The high entropy two-dimensional material Ti obtained by Example 1 of the present invention 0.4 V 0.15 Cr 0.15 Nb 0.15 Ta 0.15 Double logarithmic coordinates of the temperature sensitivity of the thin film resistance thermometer prototype device prepared by Se2.

[0040] Figure 5 The high entropy two-dimensional material Ti obtained by using Example 1 of the present invention 0.4 V 0.15 Cr 0.15 Nb 0.15 Ta 0.15The resistance variation curves of the prototype device of thin film resistance thermometer prepared by Se2 at the initial stage and after 1000 thermal shocks.

[0041] Figure 6 The high entropy two-dimensional material Ti obtained by Example 1 of the present invention 0.4 V 0.15 Cr 0.15 Nb 0.15 Ta 0.15 The resistance change of the prototype device of the thin film resistance thermometer prepared by Se2 before and after 1000 thermal shocks divided by the initial resistance value at the corresponding temperature.

[0042] Figure 7 The high entropy two-dimensional material Ti obtained by Example 1 of the present invention 0.4 V 0.15 Cr 0.15 Nb 0.15 Ta 0.15 The temperature calibration deviation of the prototype device of the thin film resistance thermometer prepared by Se2, the ordinate value is obtained by dividing ΔR by d(ΔR) / dT.

[0043] Figure 8 The high entropy two-dimensional material Ti obtained by Example 2 of the present invention 0.6 V 0.1 Cr 0.1 Nb 0.1 Ta 0.1 The resistance curve of the prototype device of thin film resistance thermometer prepared by Se2 versus temperature

[0044] Fig. 9 The high entropy two-dimensional material Ti obtained by Example 2 of the present invention 0.6 V 0.1 Cr 0.1 Nb 0.1 Ta 0.1 The magnetoresistance effect of the prototype device of thin film resistance thermometer prepared by Se2 at 9T is comparable to that of the commercial Cernox.

[0045] Fig.10 The high entropy two-dimensional material Ti of Example 3 of the present invention 0.2 V 0.2 Cr 0.2 Nb 0.2 Ta 0.2 X-ray diffraction spectrum of SSe single crystal.

[0046] Fig.11 The high entropy two-dimensional material Ti obtained by Example 3 of the present invention 0.2 V 0.2 Cr 0.2 Nb0.2 Ta 0.2 The resistance value of the resistance thermometer prototype device prepared by SSe changes with temperature.

[0047] Fig.12 The high entropy two-dimensional material Ti obtained by Example 3 of the present invention 0.2 V 0.2 Cr 0.2 Nb 0.2 Ta 0.2 Temperature calibration deviation change curve of the prototype device of thin-film resistance thermometer prepared by SSe after irradiation.

[0048] Fig.13 The high entropy two-dimensional material Sc obtained by Example 4 of the present invention 0.05 Mo 0.05 W 0.05 Cr 0.05 Ti 0.3 V 0.1 Nb 0.1 Ta 0.1 Zr 0.1 Hf 0.1 The resistance value of the resistance thermometer prototype device prepared by Se2 changes with temperature. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below in conjunction with specific embodiments. The given examples are only for illustrating the present invention, rather than for limiting the scope of the present invention.

[0050] Example 1

[0051] The component used is Ti 0.4 V 0.15 Cr 0.15 Nb 0.15 Ta 0.15 Se2 is a high-entropy two-dimensional material used to prepare a resistive thermometer prototype device with an operating temperature of 5-400K.

[0052] First, the selected elements were mixed in a ratio of Ti:V:Cr:Nb:Ta:Se=0.4:0.15:0.15:0.15:0.15:2, and the mixture was sealed in a vacuum tube and fired at 1000°C. After keeping the temperature for one day, the mixture was cooled to obtain Ti 0.4 V 0.15 Cr 0.15 Nb 0.15 Ta 0.15 Polycrystalline sample of Se2.

[0053] Then, 1 g of powdered Ti 0.4 V 0.15 Cr 0.15 Nb0.15 Ta 0.15 The Se2 polycrystalline sample was sealed with 50 mg of iodine and iodine was used as the transmission medium. The two ends of the quartz tube were placed in a tube furnace at 1050°C and 950°C for 20 days. After cooling to room temperature by quenching, a bulk single crystal of a two-dimensional high entropy material was obtained. The optical photograph of the single crystal is shown in Figure 1. Figure 1 As shown. Through energy dispersive X-ray spectroscopy (EDX) component analysis, it is found that the actual composition is close to the nominal ratio, as shown in Figure 2 shown.

[0054] Secondly, use a mask hard mask to make an electrode mask on a sapphire glass substrate, and use thermal evaporation to plate a metal electrode on the substrate. The metal materials used are Cr and Au to obtain the bottom electrode required for the device. Use Scotch tape to dissociate the high-entropy two-dimensional material single crystal into a master tape, use polydimethylsiloxane (PDMS) film to tear off a thin layer of sample from the master tape, find a suitable flat thin film sample with a thickness of 100nm under a metallographic microscope, and transfer it to the pre-made bottom electrode. Slowly lift the PDMS to make good contact between the sample film and the bottom electrode. Use hexagonal boron nitride (h-BN) as a protective layer, dissociate it into a master tape using Scotch tape, and also use PDMS to tear it off, and select a large area of ​​flat thin film and transfer it to the sample surface, so that the hexagonal boron nitride is well fitted with the sample, electrode and substrate without bubbles, forming a Figure 3 The device shown.

[0055] The standard four-wire method was used to measure the resistance of the prototype device. The resistance value changed with temperature as shown in Figure 4 shown. Figure 4 The results show that the resistance of the prototype device changes monotonically with temperature in the working temperature range. As the temperature decreases, the temperature sensitivity increases, indicating that the prototype device has good temperature resolution at low temperatures.

[0056] To test the ability of the prototype device to withstand thermal shock, the prototype device was subjected to up to 1000 thermal cycles. The resistance change with temperature before and after the thermal cycle is shown in Figure 2. Figure 5 The ratio of the difference before and after to the original resistance is less than 2% in the entire working temperature range, as shown in Figure 6 The temperature calibration deviation is less than 1K, as shown in Figure 7 shown.

[0057] Example 2

[0058] The component used is Ti 0.6 V 0.1 Cr 0.1 Nb 0.1 Ta 0.1 Se2 is a high-entropy two-dimensional material used to prepare a resistive thermometer prototype device with an operating temperature of 1.6-400K.

[0059] First, the selected elements are mixed in a ratio of Ti:V:Cr:Nb:Ta:Se=0.6:0.1:0.1:0.1:0.1:2, and then the tube is sealed in a vacuum and fired at 1000°C. After keeping the temperature for one day, the tube is cooled to obtain Ti. 0.6 V 0.1 Cr 0.1 Nb 0.1 Ta 0.1 Polycrystalline sample of Se2.

[0060] Then, 1 g of powdered Ti 0.6 V 0.1 Cr 0.1 Nb 0.1 Ta 0.1 The Se2 polycrystalline sample and 50 mg of iodine were placed in a tubular furnace with argon gas, and the regional temperature was set to 1050°C. A sapphire glass substrate was placed at the rear end of the gas flow, and the temperature at the substrate was set to 950°C. The reaction lasted for 30 minutes. The film was cooled to room temperature by quenching to obtain a thin film of a two-dimensional high entropy material. The thin film device preparation method is the same as that in Example 1.

[0061] The standard four-wire method was used to measure the resistance of the prototype device. The resistance value changed with temperature as shown in Figure 8 shown. Figure 8 The results show that the prototype device has good temperature resolution down to 1.6K.

[0062] To verify the magnetic field stability of the prototype device, a 9T magnetoresistance test was performed at 2K. The results are as follows: Fig. 9 The magnetoresistance is less than 1% at 9T, indicating that the device is suitable for use in strong magnetic field environments such as monitoring the temperature of superconducting magnets.

[0063] Example 3

[0064] The component used is Ti 0.2 V 0.2 Cr 0.2 Nb 0.2 Ta 0.2 The high entropy two-dimensional material of SSe is used to prepare a prototype device of a resistance thermometer with an operating temperature of 0.3-400 K. The single crystal growth method is the same as that in Example 1.

[0065] The high entropy two-dimensional material Ti prepared in this embodiment 0.2 V 0.2 Cr 0.2 Nb 0.2 Ta 0.2 The X-ray diffraction spectrum of SSe single crystal is as follows Fig.10 shown. Fig.10The diffraction peaks are sharp and no impurity peaks appear, which indicates that a single phase is formed and that the anion S can be well incorporated into the lattice. The device directly selects a flat block material, uses silver glue to bond 4 silver wires, and is encapsulated with a high thermal conductivity epoxy resin.

[0066] The standard four-wire method was used to measure the resistance of the prototype device. The resistance value changed with temperature as shown in Fig.11 shown. Fig.11 The results show that the prototype device has good temperature resolution down to 0.3K.

[0067] In order to test the radiation resistance of the prototype device, the prototype device was irradiated with γ-rays with an irradiation intensity of 0.007Gy / s and a total radiation dose of 10kGy. The temperature calibration deviation after irradiation is as follows Fig.12 As shown in the figure, the temperature calibration deviation caused by γ-rays is less than 1K. This shows that the device is expected to be used in strict environments such as particle accelerators and aerospace.

[0068] Example 4

[0069] The utilization component is Sc 0.05 Mo 0.05 W 0.05 Cr 0.05 Ti 0.3 V 0.1 Nb 0.1 Ta 0.1 Zr 0.1 Hf 0.1 Se2 high entropy two-dimensional material, a resistance thermometer prototype device with an operating temperature of 15-400 K is prepared. The single crystal growth method is the same as that in Example 1. The thin film device preparation method is the same as that in Example 1.

[0070] The standard four-wire method was used to measure the resistance of the prototype device. The resistance value changed with temperature as shown in Fig.13 shown. Fig.13 The results show that the prototype device has good temperature resolution capability down to 15K.

Claims

1. Use of a high entropy two-dimensional material in a thermometer, wherein: The temperature sensing element of the thermometer is made of a material having the following chemical formula composition: HEX 2±δ ,0≤δ≤0.5; HE is 3-15 metal elements selected from Groups IIIB to VB of the periodic table; the atomic percentage of each metal element is independently 3%-60% and the sum of the atomic percentages of each metal element is equal to 100%; X is one or more selected from O, S, Se and Te.

2. Use of the high entropy two-dimensional material in a thermometer according to claim 1, wherein: The operating temperature range of the thermometer is 0.3K-420K.

3. Use of the high entropy two-dimensional material in a thermometer according to claim 1, wherein: The temperature sensing element is composed of the material in the form of a block, a sheet or a film; Preferably, the material is single crystal or polycrystalline.

4. Use of the high entropy two-dimensional material in a thermometer according to claim 1, wherein: The resistance value of the thermometer is 1 milliohm to 500 megohm.

5. A thermometer, wherein: The temperature sensing element of the thermometer is composed of a material having the following chemical formula: HEX 2±δ ,0≤δ≤0.5; HE is 3-15 metal elements selected from Groups IIIB to VB of the periodic table; the atomic percentage of each metal element is independently 3%-60% and the sum of the atomic percentages of each metal element is equal to 100%; X is one or more selected from O, S, Se and Te.

6. The thermometer according to claim 5, wherein: The operating temperature range of the thermometer is 0.3K-420K.

7. The thermometer according to claim 5, wherein: The temperature sensing element is composed of the material in the form of a block, a sheet or a film; Preferably, the material is single crystal or polycrystalline.

8. The thermometer according to claim 5, wherein: The resistance value of the thermometer is 1 milliohm to 500 megohm.

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