Rapid preparation method of CoSb3-based thermoelectric material and induction melting and sintering device

Abstract

The invention discloses a rapid preparation method of a CoSb3-based thermoelectric material and an induction melting and sintering device, and the preparation method comprises the steps: calculating an element ratio, weighing Cu powder, B powder, Co powder, Sb powder and Te powder obtained through calculation, mixing, and pressing into a columnar sample through a powder tablet press; putting the columnar sample into a metal cylinder mold, and then sealing the metal cylinder mold in a quartz glass tube; placing the quartz glass tube in an induction melting furnace, vacuumizing the quartz glass tube by using a vacuum pump, heating at certain induction heating power, taking out the metal cylinder mold from the quartz glass tube after heating for a period of time, quenching, taking out a sample, and grinding the prepared product to obtain a final finished product; according to the method, the skutterudite compound Cu < 0.1 > BCo < 4 > Sb < 11 >. 5 Te < 0.5 > is successfully prepared under the conditions of different heating powers and heating times by utilizing the rapid heating and electromagnetic stirring effects of electromagnetic induction smelting.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thermoelectric materials, in particular, the present application relates to a rapid preparation method of CoSb3-based thermoelectric material and an induction melting and sintering device. BACKGROUND

[0002] The cobaltite compound is named after being found in mineral form, and its general formula can be represented as AB3 (in the formula: A: Ir, Co, Ni, Fe, Rh, etc. metal elements, B: As, Sb, P non-metal), and the unit cell of the cobaltite CoSb3-based material contains a special cage structure, and the cobaltite thermoelectric material with natural pores has attracted the attention of researchers.

[0003] The binary pure CoSb3-based material has good electrical conductivity and Seebeck coefficient, and has excellent material electrical transport performance; but its lattice thermal conductivity is also high, thereby reducing the ZT value of the material. For this reason, many scientific researchers fill different atoms in the cage pores of the unit cell, so that the thermal transport performance is similar to glass. This is because the different atoms will undergo anharmonic motion in the pores, causing phonon scattering and reducing the thermal conductivity of the material. Therefore, in the research direction of CoSb3 semiconductor, the electrical resistivity and thermal conductivity can be optimized and reduced by element substitution doping, filling and nano-composite methods without affecting the S coefficient, thereby further improving the thermoelectric performance. The filling elements are single filling, binary filling, ternary filling, and even multi-element filling. At present, the element doping, pore filling and nano-composite method is an effective means to further optimize the thermoelectric performance of cobaltite.

[0004] Although the CoSb3-based material filling compound has good performance and strong plasticity, excellent electrical properties, and has a wide prospect in the practical application of thermoelectric materials, its lattice thermal conductivity is high, which limits its commercial development and practical application. Therefore, by improving the experimental method and filling and doping elements, the lattice thermal conductivity is effectively optimized, thereby improving the thermoelectric performance of the CoSb3-based material, and the grain and interface have a greater influence on the performance of cobaltite, which is an important research direction in recent years.

[0005] And for the preparation method of cobaltite, the following several methods are commonly used for the preparation of cobaltite: (1)Mechanical alloying method (high-energy ball milling method): through the impact, grinding and stirring technology of the ball mill to the powder or block, the powder or block material is alloyed, the grain is refined to nanometer level, the sintering ability is improved, and the mechanical chemical reaction method is finally realized. The advantages of this method are: fast reaction time, simple process flow, high efficiency, very suitable for large-scale powder production, and conducive to reducing the lattice thermal conductivity. But in the ball milling process, in order to prevent the sample from being oxidized, high-purity Co powder and Sb powder are required, and the operation is required in an oxygen-free environment. The sample collection is difficult, and impurities are easily introduced in the operation process.

[0006] (2) Melt spinning method: first, the melt is sprayed in a fluid manner onto a high-speed rotating copper roller, and then spun out to form a strip-shaped product with a nano-scale microstructure. This method has the advantages of short preparation period, controllable microstructure of raw materials, etc., but it is not suitable for large-scale preparation due to the small amount of sample required and the easy blocking of the circular hole at the bottom of the glass tube.

[0007] (3) Solid phase reaction method: first, use pure powder or compound as starting material, mix according to the chemical ratio, then put into high temperature atmosphere sintering furnace, anneal and keep warm for a long time, form a chemical reaction process. Finally, the bulk is obtained by densification sintering. The method has the advantages of effective peritectic reaction to produce impurities, high yield, high selectivity, no solvent, etc., but the preparation period is long, mostly only suitable for high temperature synthesis, time cost is high, etc.

[0008] Therefore, in view of the above problems, the present application aims to design a new preparation method. Based on the existing experimental conclusions, the Cu, B and Te elements are doped into the CoSb3 system to form a multi-doped skutterudite material, and the inductive melting sintering technology is used to successfully prepare the skutterudite compound Cu 0.1 BCo4Sb 11.5 Te 0.5 . SUMMARY

[0009] To solve the above technical problems, the present application provides a rapid preparation method of CoSb3-based thermoelectric material and an inductive melting sintering device. The inductive melting sintering technology is used to quickly and efficiently prepare skutterudite thermoelectric material by using the rapid heating and electromagnetic stirring of electromagnetic induction melting, so as to realize the rapid and efficient preparation from powder raw material to finished sample, thereby solving the corresponding technical problems in the above background technology.

[0010] To achieve the above purpose, the technical scheme adopted by the present application is as follows: In a first aspect, the present application relates to a rapid preparation method of CoSb3-based thermoelectric material, Step one: calculate Cu 0.1 BCo4Sb 11.5 Te 0.5 Elemental ratio of skutterudite compound, and the mass of 4N Cu powder, B powder, Co powder, Sb powder and Te powder calculated is weighed; Step two: the weighed Cu powder, B powder, Co powder, Sb powder and Te powder are mixed and pressed into a columnar sample using a powder tablet press; Step three: the columnar sample in step two is loaded into a metal cylinder mold, and then sealed in a quartz glass tube; Step four: the quartz glass tube is placed in an induction melting furnace, vacuum is first pumped to the quartz glass tube, then heated at a certain induction heating power, after a period of heating, the metal cylinder mold is taken out from the quartz glass tube for quenching and cooling, then the sample is taken out, and the product is prepared; Step five: the product in step four is polished to obtain the final product.

[0011] Preferably, the particle size of the Cu powder, B powder, Co powder, Sb powder and Te powder is about 200 mesh, and the mixing process in step two is high-energy ball milling under a nitrogen-filled environment.

[0012] Preferably, the size of the columnar sample is 10mm in diameter and 3.50-4.00mm in thickness.

[0013] Preferably, the induction heating in step four uses an induction melting furnace.

[0014] Preferably, the induction heating power in step four is 221-600W.

[0015] Preferably, the induction heating time in step four is 1-30min.

[0016] Preferably, the induction heating power in step four is 600W, and the induction heating time in step four is 200s.

[0017] In a second aspect, the present application relates to a CoSb3-based thermoelectric material prepared by the rapid preparation method of the CoSb3-based thermoelectric material described above.

[0018] In a third aspect, the present application relates to a rapid preparation induction melting sintering device for CoSb3-based thermoelectric material, which is applied to the rapid preparation method of the CoSb3-based thermoelectric material described above, and comprises: Quartz glass tube, both ends of the quartz glass tube are sealed with refractory plunger; An inductive heating body is a metal cylinder mold placed inside the quartz glass tube, the metal cylinder mold is a hollow structure, both ends of the hollow structure are sealed with sealing material, and the middle part of the hollow structure is placed with a columnar sample; A vacuumizing device is arranged on the refractory plunger at one end of the quartz glass tube.

[0019] Preferably, the vacuumizing device comprises a sealing flange arranged on the refractory plunger, the sealing flange is communicated with an air channel, one end of the air channel is provided with an air inlet hole, the other end of the air channel is provided with an air outlet hole, and the top end of the air channel is provided with a vacuum gauge.

[0020] Compared with the prior art, the application has the following beneficial effects: 1. In the technical scheme of the application, CoSb3-based thermoelectric material is taken as a research object, based on existing experimental conclusions, and in view of the existing problems of doped skutterudite, Cu, B and Te elements are doped into the CoSb3 system to form a multi-doped skutterudite material. The atomic radius of Cu is relatively moderate, and Cu has the advantages of high thermal conductivity and electrical conductivity, and low resistivity. The atomic radius of boron is small (0.098 nm), and boron is distributed along the grain boundary. The addition of boron can effectively refine the grain size of the material, improve the mobility of carriers, and improve the thermoelectric performance and interface performance of the material. Te and Sb elements are adjacent atoms, and their radii are similar, so they can be used as replacement atoms for Sb. By doping Te, n-type conductive skutterudite can be obtained from the skutterudite-based material. The n-type skutterudite has a large effective mass of electrons, and its Seebeck coefficient is larger than that of the p-type sample under the same carrier concentration. The Te-doped skutterudite significantly improves the electrical transport performance and reduces the thermal conductivity to a certain extent. By co-doping multiple different elements, the mass fluctuation of the CoSb3-based material atoms can be increased, which can reduce the lattice thermal conductivity. At the same time, the introduction of new elements also increases the surface defects of the grain boundary, which enhances the phonon scattering, thereby reducing the thermal conductivity. According to the thermoelectric figure of merit formula, the decrease in thermal conductivity can improve the overall thermoelectric performance under the condition of constant electrical conductivity.

[0021] 2. In the technical scheme of the application, the sample structure is dense after sintering in a magnetic field environment, the grain boundary is clear, there are a small amount of tiny pores, the particle distribution of the sample is relatively uniform, and the grain size is mostly in the micro-nanometer level. The small particle size increases the Cu 0.1 BCo4Sb 11.5 Te 0.5 The grain boundary of the sample, thereby improving the scattering of heat-carrying phonons, optimizing the lattice thermal conductivity of the skutterudite, and introducing a magnetic field environment to make the internal grains of the sample have preferred orientation.

[0022] 3、The advantage of the present application is that: based on the magnetic field condition, low-temperature solid-phase reaction preparation of sample Cu 0.1 BCo4Sb 11.5 Te 0.5 The Seebeck coefficient of the sample Cu 0.1 BCo4Sb 11.5 Te 0.5 The Seebeck coefficient is negative, indicating that the synthesized sample has typical n-type semiconductor, and the Seebeck coefficient increases with the increase of preparation temperature, which is due to the occurrence of bipolar effect, and the intrinsic excitation can be ignored at lower temperature, resulting in the increase of Seebeck coefficient, when the temperature rises, the lattice vibration increases, resulting in the increase of internal intrinsic excitation, increasing the effect of Seebeck coefficient, therefore, the external magnetic field can assist the synthesis of composite Cu 0.1 BCo4Sb 11.5 Te 0.5 The compound has the effects of energy saving, consumption reduction and resource saving. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The figure is the schematic diagram of the induction melting and sintering device for rapid preparation of CoSb3-based thermoelectric material in the application; Figure 2 The figure is the XRD test result graph of the sample prepared under different heating power in the application; Figure 3 The figure is the XRD test result graph of the sample prepared under different heating time in the application; Figure 4 The figure is the cross-section scanning electron microscope graph of CoSb3-based thermoelectric material sample in the embodiment of the application, the induction heating power is 600W, and the induction heating time is 5min; Figure 5 The figure is the Seebeck coefficient and resistivity of CoSb3-based thermoelectric material sample in the application, and the change relation graph with heating power; Figure 6 The figure is the power factor of CoSb3-based thermoelectric material sample in the application, and the change relation graph with heating power; Figure 7 The figure is the Seebeck coefficient and resistivity of CoSb3-based thermoelectric material sample in the application, and the change relation graph with heating time; Figure 8 The figure is the power factor of CoSb3-based thermoelectric material sample in the application, and the change relation graph with heating time; The markings in the accompanying drawings are: 1-vacuum gauge, 2-air outlet, 3-sealing flange, 4-refractory plunger, 5-quartz glass tube, 6-sealing material, 7-columnar sample, 8-induction heating body, 9-induction coil, 10-air inlet. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0026] The raw materials used in this preparation method are all high-purity metal powders and non-metallic powders, including: high-purity Cu powder (4N), high-purity Te powder (4N), high-purity B powder (4N), Co powder (4N), and Sb powder (4N). The parameters of the raw materials are shown in Table 1:

[0027] The main experimental instruments required in this preparation method are: electronic balance, all-round planetary ball mill (ball mill, grinding balls), vacuum drying oven, tableting columnar mold, powder tablet press, induction melting furnace, XRD diffractometer, SEM tester, etc. The instruments and their models used in this experiment are shown in Table 2 below:

[0028] The specific preparation process steps are as follows: Step 1: Calculate the skutterudite compound (Cu 0.1 BCo4Sb 11.5 Te 0.5 ) element ratio Calculation and weighing of experimental raw material mass: The total mass of the experimental drugs is 30g. According to the relevant formula , according to the chemical formula (Cu 0.1 BCo4Sb 11.5 Te 0.5 ) Calculate the mass of Cu powder, Co powder, Sb powder, Te powder and B powder and weigh them. g / mol, g / mol, g / mol, g / mol.

[0029] Step 2: uniform mixing The mass of Cu powder, Co powder, Sb powder, Te powder and B powder is calculated, and the required mass is weighed using a decimal electronic balance. Then, the weighed powder is placed in a cleaned and dried ball mill tank. It is noted that the weighed mass can be slightly larger than the actual calculated result because there is a certain loss of raw materials during the weighing process and the mixing and tabletting process. The raw materials are weighed in the order of decreasing mass and then transferred to the ball mill tank. Then, the ball mill tank is poured into the assembled ball mill, and the ball mill tank is vacuumized. The ball mill tank is placed in a planetary ball mill under N2 atmosphere. The program parameters of the ball mill are set, and the ball mill is started. After 2 hours, the ball mill is taken out.

[0030] Step 3: tabletting and forming After the ball mill program is running well, the ball mill tank is taken out of the ball mill, and the mixed powder in the ball mill tank is poured into an agate mortar. The ground powder is weighed using an electronic balance, and 1.65-1.8 g of the ground powder is placed into a tabletting die. After the die is assembled, it is moved under the pressure rod of the tablet press. The power of the tablet press is turned on, and the pressure is adjusted (3-4 MPa). The tablet press is started, and the up or down switch is manually pressed. The tablet is pressed into a circular shape with a thickness of 3.5-4.0 mm and a height of about 10 mm. After the tablet is pressed, it is demolded and taken out. The formed circular tablet sample is placed into a prepared sample bag, labeled, and placed into a vacuum tank to prevent oxidation by air.

[0031] Step 4: sample sintering The sample sintering process uses an induction melting and sintering device, which includes: a quartz glass tube 5, both ends of which are sealed with refractory plungers 4; an induction heating body 8, which is a metal cylinder mold placed inside the quartz glass tube 5. The metal cylinder mold is hollow, and both ends of the hollow structure are sealed with sealing material 6. The middle part of the hollow structure is used to place a columnar sample. The refractory plunger 4 at one end of the quartz glass tube 5 is provided with a vacuumizing device. The vacuumizing device includes a sealing flange 3 arranged on the refractory plunger 4, which is in communication with an air duct. One end of the air duct is provided with an air inlet hole 10, the other end of the air duct is provided with an air outlet hole 2, and the top end of the air duct is provided with a vacuum gauge 1. The induction melting and sintering device is arranged in an induction melting furnace for induction heating. The induction melting furnace is an HT-25AB type induction melting furnace, in which an induction coil 9 is arranged.

[0032] The specific sintering process is as follows: the pressed sample is loaded into a metal cylinder mold, then sealed in a quartz glass tube 5, and then the quartz glass tube 5 is placed in an induction melting furnace. First, the quartz glass tube 5 is vacuumed by a vacuum pump, then heated at different induction heating powers, and after a certain time of heating, the metal cylinder mold is taken out of the quartz glass tube 5 for quenching cooling, and then the sample is taken out.

[0033] Step 5: Sample polishing After the sample is sintered and cooled to room temperature, wear gloves, take clean sandpaper, and polish it on the sandpaper with tweezers until the surface impurities are removed.

[0034] Step 6: Sample detection The polished sintered sample is cleaned by ultrasonic wave for about 30 minutes, dried, and then tested for Seebeck coefficient, r value (resistivity), XRD detection, and SEM detection. The samples obtained in this experiment are detected by XRD and SEM to measure the lattice index, characteristic peak, composition, structure, microstructure, surface morphology, and microstructure of the samples. The purity and microstructure of the prepared samples and the electrical properties are studied to obtain the preparation rules of CoSb3-based thermoelectric materials under magnetic field environment and element doping.

[0035] Step 7: Analyze data According to the analysis of the pictures obtained by XRD, the lattice index, characteristic peak, and composition can be analyzed. According to the SEM pictures, the microstructure and microstructure can be analyzed. According to the test of electrical properties, the Seebeck coefficient and resistivity are tested, and the power factor is calculated by formula to obtain the change rule of the electrical properties of the sample.

[0036] Examples 1-7: The preparation process steps described above are used for preparation, except for the holding temperature and holding time, and the rest of the parameters remain unchanged, wherein: In example 1, the inductive heating power in step 4 is 221 W, and the inductive heating time in step 4 is 200 s; In example 2, the inductive heating power in step 4 is 300 W, and the inductive heating time in step 4 is 200 s; In example 3, the inductive heating power in step 4 is 400 W, and the inductive heating time in step 4 is 200 s; In example 4, the inductive heating power in step 4 is 500 W, and the inductive heating time in step 4 is 200 s; The inductive heating power in step 4 in Example Five is 600W, and the inductive heating time in step 4 is 200s; The inductive heating power in step 4 in Example Six is 700W, and the inductive heating time in step 4 is 200s.

[0037] XRD data analysis of the sample: Examples One to Six are based on the reaction of Cu 0.1 BCo4Sb 11.5 Te 0.5 The sample is polished on both sides, ultrasonically cleaned and dried, ground and crushed into powder, and XRD-6100 type XRD powder polycrystalline diffractometer is used for X-ray diffraction analysis under the condition of scanning step of 4° / min and diffraction angle of 20-80°, as shown in Figure 2 .

[0038] As Figure 2 shown, the Cu 0.1 BCo4Sb 11.5 Te 0.5 sample XRD spectrum, Examples One to Six are sintered from different heating powers to obtain Cu 0.1 BCo4Sb 11.5 Te 0.5 The XRD diffraction analysis spectrum of the sample shows that all the main peaks of the sample correspond to the standard card of CoSb3, in addition to this, no other impurity phase appears in all the XRD spectra of the sample, which shows that the main component of the synthesized sample is CoSb3, and the added elements Cu, B and Te are all dissolved into the CoSb3 crystal structure. When the inductive heating power is 700W, the sample diffraction peak slightly shifts to low angle, because the increase of sintering power increases the sintering temperature, and the lattice constant increases due to the filling of elements Cu, B and Te into the porosity of skutterudite, which causes the expansion of the unit cell, resulting in the shift of the sample diffraction peak.

[0039] Examples Seven to Fourteen: The preparation process steps are prepared as described above, except that the holding temperature and holding time are changed, and the other parameters remain unchanged, wherein: The inductive heating power in step 4 in Example Seven is 600W, and the inductive heating time in step 4 is 0.5min; The inductive heating power in step 4 in Example Eight is 600W, and the inductive heating time in step 4 is 1min; The inductive heating power in step 4 in Example Nine is 600W, and the inductive heating time in step 4 is 5min; The inductive heating power in step 4 in the example ten is 600W, and the inductive heating time in step 4 is 15min; The inductive heating power in step 4 in the example eleven is 600W, and the inductive heating time in step 4 is 30min.

[0040] The Cu 0.1 BCo4Sb 11.5 Te 0.5 The sample is polished, ultrasonically cleaned and dried, ground and broken into powder, and XRD-6100 type XRD powder polycrystalline diffractometer is used for X-ray diffraction analysis under the condition of scanning step of 4° / min and diffraction angle of 20-80°, as shown in Figure 3 The sample is polished, ultrasonically cleaned and dried, ground and broken into powder, and XRD-6100 type XRD powder polycrystalline diffractometer is used for X-ray diffraction analysis under the condition of scanning step of 4° / min and diffraction angle of 20-80°, as shown in

[0041] Figure 3 The Cu 0.1 BCo4Sb 11.5 Te 0.5 The sample XRD spectrum. From the XRD diffraction analysis spectrum, when the inductive heating time is 0.5min, the main peak of the sample does not correspond to the standard card of CoSb3, and only the diffraction peak of element Te appears in the spectrum, indicating that the skutterudite compound CoSb3 cannot be synthesized under the condition of inductive heating power of 600W and inductive heating time of 0.5min. When the inductive heating time is 1-30min, all the main peaks of the sample correspond to the standard card of CoSb3, indicating that the main component of the sample is CoSb3. The experimental results show that when the inductive heating power is 600W, the lowest inductive heating time for synthesizing the skutterudite compound CoSb3 is 1min.

[0042] The sample SEM analysis: the microstructure of the sample is tested and analyzed by scanning electron microscope, Figure 4 The sample Cu 0.1 BCo4Sb 11.5 Te 0.5 The cross-sectional scanning electron microscope image, wherein Fig. (a) is a cross-sectional image with magnification of 500 times, and Fig. (b) is a cross-sectional image with magnification of 5000 times. As can be seen from the figure, there are many holes in the synthesized sample, and the holes are caused by unstable inductive heating power. As can be seen from Fig. (b), the grain boundary of the sample is not obvious, and the crystallinity of the grain is poor, which is consistent with the test results of XRD.

[0043] Sample Cu 0.1 BCo4Sb 11.5 Te 0.5 Analysis of electrical properties: Figure 5 For sample Cu 0.1 BCo4Sb 11.5 Te 0.5 The relationship diagram of Seebeck coefficient S, resistivity p and different heating power under the condition of heating time of 200s. From Figure 5 It can be seen that the resistivity of the samples of example one to example six decreases first and then increases with the increase of heating power, first decreases linearly from heating power of 221W to 400W, then slowly decreases to 500W to obtain the minimum resistivity of p = 1.51 mW·cm, and then sharply rises; the absolute value of the Seebeck coefficient of the sample increases first and then decreases with the increase of heating power, first increases slowly from heating power of 221W to 500W, then sharply increases to 600W to obtain the maximum absolute value of the Seebeck coefficient of S = 176.88 μVK -1 , and then linearly decreases.

[0044] Figure 6 For sample Cu 0.1 BCo4Sb 11.5 Te 0.5 The relationship diagram of power factor and different heating power under the condition of heating time of 200s. From Figure 5 It can be seen that the power factor of the samples of example one to example six increases first and then decreases with the increase of heating power, first increases slowly from heating power of 221W to 600W to obtain the maximum power factor of PF = 1819.01 μW / mK 2 , and then linearly decreases. Overall analysis shows that the best sintering power of sample Cu 0.1 BCo4Sb 11.5 Te 0.5 is 600W.

[0045] Under the condition of the best heating power of 600W, the influence of different heating time on the resistivity p, Seebeck coefficient S, power factor PF, etc. of sample Cu 0.1 BCo4Sb 11.5 Te 0.5 is explored, and the best heating time of the sample is investigated.

[0046] Figure 7 For sample Cu 0.1 BCo4Sb 11.5 Te 0.5 The relationship diagram of Seebeck coefficient S, resistivity p and heating time under the condition of the best heating power of 600W. FromFigure 7 It can be seen that with the increase of heating time, the resistivity of the samples of Example Seven-Example Eleven shows a trend of first decreasing and then increasing, and the turning point appears when the heating power is 600 W and the heating time is 5 min, and the sample obtains the lowest resistivity of p = 1.66 mW·cm; the absolute value of the Seebeck coefficient of the sample shows a trend of first decreasing and then increasing with the increase of heating time, and the absolute value of the Seebeck coefficient reaches the highest value of S = 169.71 μVK under the condition of a heating power of 600 W and a heating time of 1 min -1 , and the lowest absolute value of the Seebeck coefficient is S = 151.83 μVK when the heating power is 600 W and the heating time is 15 min -1 .

[0047] Figure 8 Cu 0.1 BCo4Sb 11.5 Te 0.5 The relationship diagram of the power factor under the condition of the optimal heating power of 600 W and the heating time. From Figure 8 it can be seen that the power factor of the samples of Example Seven-Example Eleven shows a gradually decreasing trend with the increase of heating time, and the sample obtains the maximum power factor of PF = 1540.11 μW / mK under the condition of a heating power of 600 W and a heating time of 1 min 2 . Combined with Figure 6 and Figure 8 analysis, it is concluded that the optimal induction heating time of the sample Cu 0.1 BCo4Sb 11.5 Te 0.5 is 200 s.

[0048] By using the induction melting sintering technology, the elements of Cu, B, Te, etc. are doped to CoSb3, and the sample Cu 0.1 BCo4Sb 11.5 Te 0.5 is prepared by using the rapid heating and electromagnetic stirring effect of electromagnetic induction melting. The influence law of different heating powers, different heating times and element doping on the microstructure and electrical properties of the sample Cu 0.1 BCo4Sb 11.5 Te 0.5 is examined, and the following conclusions are mainly obtained: when the heating time is 200 s, the sample obtains the lowest resistivity of 1.51 mW·cm under the condition of a heating power of 500 W; the lowest heating time of the skutterudite compound Cu 0.1 BCo4Sb 11.5 Te 0.5 is 1 min when the heating power is 600 W, and the highest absolute value of the Seebeck coefficient is 176.88 μVK when the heating time is 200 s.-1 The maximum power factor is 1819.01 μW / mK 2 ; Induction heating preparation sample Cu 0.1 BCo4Sb 11.5 Te 0.5 The optimal preparation condition is that the heating power is 600 W and the heating time is 200 s.

[0049] While the embodiments of the application have been shown and described, it is to be understood that the embodiments can be varied, modified, substituted and changed by those skilled in the art without departing from the principles and spirit of the application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for rapidly preparing CoSb3-based thermoelectric materials, characterized in that: Step 1: Calculate Cu 0.1 BCo4Sb 11.5 Te 0.5 The element ratio of the skutterudite compound, and weighing 4N grade Cu powder, B powder, Co powder, Sb powder, and Te powder according to the calculated mass; Step 2: Mix the weighed Cu powder, B powder, Co powder, Sb powder, and Te powder and press them into columnar samples using a powder tablet press (7); Step 3: Place the columnar sample (7) in step 2 into a metal cylinder mold and then seal it in a quartz glass tube (5); Step 4: placing the quartz glass tube (5) in an induction melting furnace, first evacuating the quartz glass tube (5) with a vacuum pump, then heating it with a certain induction heating power, and after heating for a period of time, removing the metal cylinder mold from the quartz glass tube (5), quenching and cooling it, and then taking out the sample to obtain a product; Step 5: Polish the product in step 4 to obtain the final product.

2. A method for rapidly preparing a CoSb3-based thermoelectric material according to claim 1, characterized in that: The particle size of the Cu powder, B powder, Co powder, Sb powder and Te powder is about 200 mesh, and the mixing process in step 2 is to perform high-energy ball milling to mix them uniformly in a nitrogen-filled environment.

3. The rapid preparation method of CoSb3-based thermoelectric material according to claim 2, characterized in that: The columnar sample has a diameter of 10 mm and a thickness of 3.50 to 4.00 mm.

4. A method for rapidly preparing CoSb3-based thermoelectric materials according to claim 3, characterized in that: The induction heating in step 4 uses an induction melting furnace.

5. A method for rapidly preparing CoSb3-based thermoelectric materials according to claim 4, characterized in that: The induction heating power in step 4 is 221-600W.

6. A method for rapidly preparing CoSb3-based thermoelectric materials according to claim 5, characterized in that: The induction heating time in step 4 is 1-30 minutes.

7. A method for rapidly preparing CoSb3-based thermoelectric materials according to claim 6, characterized in that: The induction heating power in step 4 is 600 W, and the induction heating time in step 4 is 200 s.

8. A CoSb3-based thermoelectric material, characterized in that The material is prepared by the rapid preparation method of a CoSb3-based thermoelectric material according to any one of claims 1 to 7.

9. An induction melting and sintering device for rapid preparation of CoSb3-based thermoelectric materials, used in a rapid preparation method of a CoSb3-based thermoelectric material according to any one of claims 1 to 7, characterized in that: include: A quartz glass tube (5), wherein both ends of the quartz glass tube (5) are sealed with refractory plungers (4); An induction heating body (8), wherein the induction heating body (8) is a metal cylinder mold, the metal cylinder mold is placed inside the quartz glass tube (5), the metal cylinder mold is a hollow structure, both ends of the hollow structure are sealed with a sealing material (6), and a columnar sample is placed in the middle of the hollow structure; A vacuum device is provided on the refractory plunger (4) at one end of the quartz glass tube (5).

10. The induction melting and sintering device for rapid preparation of CoSb3-based thermoelectric materials according to claim 9, characterized in that: The vacuum pumping device includes a sealing flange (3) arranged on a refractory plunger (4), the sealing flange (3) being connected to an air passage, an air inlet (10) being arranged at one end of the air passage, an air outlet (2) being arranged at the other end of the air passage, and a vacuum gauge (1) being arranged at the top end of the air passage.

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