CN114655937A - Precursor powder of 3D printing piece of bismuth telluride-based thermoelectric material and preparation method thereof - Google Patents
Precursor powder of 3D printing piece of bismuth telluride-based thermoelectric material and preparation method thereof Download PDFInfo
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Abstract
The application discloses precursor powder of a 3D printing piece of a bismuth telluride-based thermoelectric material and a preparation method thereof. The bismuth telluride-based spherical powder has the advantages of high alloying degree, good sphericity, proper particle size range (10-53 mu m), stable chemical property and good overall powder flowability, and can be directly used as precursor powder of an SLM printing process for 3D printing.
Description
Technical Field
The application relates to precursor powder of a 3D printing piece of a bismuth telluride-based thermoelectric material and a preparation method thereof.
Background
With the rapid development of global industrialization process, the demand of people to obtain electric energy by burning fossil fuel is also increasing remarkably. However, the waste heat is generated in the fossil fuel combustion process, and the exhaust gas causes environmental problems such as global warming and climate change. The thermoelectric material can directly realize the direct conversion of heat energy and electric energy, no redundant pollution is generated in the conversion process, and a device prepared by utilizing the thermoelectric material has the advantages of light weight, no noise, no rotating parts, no vibration, stable performance, long service cycle and the like. Thermoelectric material systems are various, and service temperature areas of different system materials are different. Among them, the bismuth telluride-based thermoelectric material as a room temperature/near room temperature thermoelectric material is the only thermoelectric material currently realizing commercial large-area application, and relevant researches are receiving great attention from domestic and foreign scientists at present.
In recent years, thermoelectric researchers have continuously studied bismuth telluride-based thermoelectric materials to improve thermoelectric performance, but development of thermoelectric devices and devices corresponding to the bismuth telluride-based thermoelectric materials is still slow, and the main reason is that the key for determining the large-scale application of the thermoelectric devices not only comprises the improvement of the performance of the thermoelectric materials, but also relates to a key core technology for manufacturing the thermoelectric devices. The traditional thermoelectric device preparation method is a method of material reduction manufacturing, corresponding steps such as cutting, welding and assembling are carried out on thermoelectric materials, meanwhile, the geometric shape of a formed part is limited by a regular plane shape, the related complex structures such as a curved surface and a hollow shape are difficult to realize, and the method is not suitable for preparing miniature devices. The traditional thermoelectric device processing technology has the advantages of long development chain, complex process, low reliability and low utilization rate of materials; in a practical service environment, most of heat sources do not present regular planes but present surface appearances with certain curvature or even irregular shapes (such as circular exhaust pipes for industrial production, rough surfaces of boilers of thermal power plants and the like), and thermoelectric devices prepared by the obtained planar thermoelectric materials cannot be in maximum thermal contact with heat source ends with certain radians, so that partial heat is lost, and the thermoelectric energy conversion efficiency is low. The method has the advantages of complex preparation process, higher financial investment, lower material utilization rate, lower product performance stability and lower energy conversion efficiency, and greatly limits the application of the thermoelectric material from a material end to a device end. Therefore, in order to optimize the process route of the thermoelectric device, improve the material utilization rate and the thermoelectric energy conversion efficiency of the thermoelectric device in the use environment, the shape of the heat source needs to be designed and satisfied by combining the relevant characteristics of low power, small volume and wide temperature zone of the thermoelectric device, and an advanced device manufacturing means which is easy to realize flexible design, batch production and efficient operation is developed. Compared with the traditional material reduction manufacturing technology, the rapid forming technology based on the digital model design and the 'discrete/accumulation' principle, namely the additive manufacturing (3D printing) technology, adopts a layer-by-layer stacking mode to accurately construct the design structure of the raw material, is not limited by the material type and the part shape, reduces the raw material loss to the maximum extent, and can rapidly realize the integral forming of the metal material. Selective Laser Melting (SLM) is one of the most mature techniques in 3D printing, and Laser beams with set energy density are used to selectively melt thermoelectric material metal powder layer by layer in specific areas line by line, so as to achieve the forming and manufacturing of the required shape and size of the thermoelectric material. Since there is little waste of raw materials throughout the printing manufacturing process, the shape of the thermoelectric material can be customized to maximize the energy conversion efficiency of the thermoelectric device.
The SLM process is actually a laser and powder energy transfer process. The surface morphology, microstructure, and flowability of the raw powder can affect the final molding quality and processing efficiency. Compared with irregular powder, the spherical powder can effectively increase the bulk density and the fluidity of the powder in the selective laser melting process. Currently, the reports on 3D printing research on bismuth telluride-based thermoelectric materials mainly include the use of ink printing technology (nat. energy.2018,3, 301-. The thermoelectric property of the former is lower than that of the bismuth telluride-based thermoelectric material prepared by the traditional method (the thermoelectric figure of merit of a p-type part is 0.9, and the thermoelectric figure of merit of an n-type part is 0.6), so that the thermoelectric property cannot meet the commercial application requirement; while the performance of the printed thermoelectric material is close to the commercial application level (the thermoelectric figure of merit of the p-type element is 1.1), the tedious printing process, the low powder flowability and the lack of research and development on the printing process of the n-type bismuth telluride material limit the final application of the printed thermoelectric material in commercialization. The reason for the problems associated with SLM prints in the above-described methods is that spherical powders with high sphericity and good flowability are not used as the precursor powder. Therefore, in order to solve the problems, the bismuth telluride-based spherical precursor powder meeting the SLM printing standard is prepared, and a high-quality bismuth telluride-based thermoelectric material printing piece is expected to be obtained, so that the energy conversion efficiency of the bismuth telluride-based thermoelectric device is effectively improved. However, to obtain spherical printing precursor powder with good sphericity and satisfactory particle size distribution, a key process technology involving gas atomization powder preparation is required.
In fact, on the premise of obtaining high-quality spherical bismuth telluride-based precursor powder, the development of the SLM printing process of the bismuth telluride-based thermoelectric material still faces great difficulty compared with the printing of conventional materials (such as titanium alloy, tungsten alloy, and the like), mainly due to the low melting point (volatility) and the low thermal conductivity of the bismuth telluride-based thermoelectric material itself, which are one of the challenges facing obtaining the SLM printing piece of the high-quality bismuth telluride-based thermoelectric material. Therefore, in order to finally obtain a high-quality bismuth telluride-based thermoelectric material printed product, a great deal of scientific problems mainly caused by the factors need to be deeply researched, 3D printing process parameters are continuously optimized, and an effective solution is provided as soon as possible.
Content of application
Based on the problems, the precursor powder of the 3D printing piece of the bismuth telluride-based thermoelectric material is high in alloying degree, good in sphericity, proper in particle size range (10-60 mu m), stable in chemical property and good in overall powder flowability, and can be directly used as the precursor powder of an SLM printing process for 3D printing.
Precursor powder of a 3D printing piece of a bismuth telluride-based thermoelectric material is powder prepared by carrying out gas atomization on isometric powder of a p-type or n-type bismuth telluride-based thermoelectric material.
The application also provides a preparation method of the precursor powder of the 3D printing piece of the bismuth telluride-based thermoelectric material.
A preparation method of precursor powder of the 3D printing piece of the bismuth telluride-based thermoelectric material comprises the following steps:
vacuumizing an atomization cavity, and filling flowing argon as a protective atmosphere;
secondly, atomization: conveying the equiaxial bismuth telluride powder to a working area of radio frequency high-temperature plasma, melting the equiaxial powder, cooling, and spheroidizing to spherical solid particles; the atomization air inlet pressure is 0.1-0.6MPa, the atomization temperature is 700-;
thirdly, screening the spherical solid particles into powder with the particle size distribution of 10-60 mu m and powder with the particle size distribution of 10-60 mu m;
fourthly, the powder with the particle size distribution outside 10 to 60 mu m is repeatedly atomized and sieved again, and the particle size distribution enters the fifth step when the particle size distribution is 10 to 60 mu m;
obtaining precursor powder
In one or more specific embodiments of the present application, the vacuum degree is up to 7 × 10-2Pa or less.
In one or more specific embodiments of the present application, the sieving screen is a multi-stage screen.
In one or more specific embodiments of the present application, the multi-stage screens are 120 μm, 53 μm, and 18 μm multi-stage screens.
Application principle and beneficial effect:
the bismuth telluride-based spherical powder prepared by the method has the advantages of high alloying degree, good sphericity, proper particle size range (10-60 mu m), stable chemical property and good overall powder fluidity, and can be directly used as precursor powder of an SLM printing process for 3D printing.
This application can satisfy actual material balling process demand through adjusting gas atomization powder process parameter (atomizing temperature, atomizing pressure etc.) according to printing material's different demands, has wider application scope.
This application has realized bismuth telluride base thermoelectric material gas atomization powder process to full flow 3D printing process route that SLM printed for the first time, adopts spherical powder as printing precursor powder, can continuous operation "shop powder, scanning, shaping" process in SLM printing stage, has greatly promoted the preparation efficiency of customization thermoelectric material.
Drawings
FIG. 1 is a schematic diagram of the working of gas atomization powder preparation of the present application;
FIG. 2 is a diagram of the morphology of p-type bismuth telluride spherical powder observed by a scanning electron microscope of the present application;
FIG. 3 is a diagram of the present application of scanning electron microscope for observing the morphology of n-type bismuth telluride spherical powder;
FIGS. 4-5 are graphs of the volume fraction (left y-axis)/cumulative percentage (right y-axis) of spherical powder of the present application as a function of powder particle size;
FIG. 6 is a schematic diagram of the SLM printing process of the present application;
FIGS. 7-8 are structural and phase information, and basic morphology diagrams of a bismuth telluride-based printed sample according to the present application;
FIGS. 9-10 are X-ray diffraction (XRD) patterns of SLM printed samples of the present application (parallel build direction and perpendicular build direction);
FIGS. 11-14 and FIGS. 15-18 are graphs of thermoelectric properties in parallel build direction and perpendicular build direction as a function of temperature for prints of the bismuth telluride-based thermoelectric material of example 5 and prints of the original sample and annealed p-type and n-type bismuth telluride-based thermoelectric materials of example 7;
FIG. 19 is a diagram of equiaxial powder morphology observed by an equiaxial powder scanning electron microscope of a p-type bismuth telluride-based thermoelectric material;
FIG. 20 is a scanning electron microscope of equiaxial powder of the n-type bismuth telluride-based thermoelectric material for observing the morphology of spherical powder;
FIG. 21 is a molten pool map of various printing parameters of the present application.
Detailed Description
The present application will be further described with reference to the accompanying drawings.
Example 1
A method for preparing bismuth telluride based spherical powder comprises the following steps:
preparing commercial isometric powder of p-type (or n-type) bismuth telluride-based thermoelectric material, wherein the average particle size of the powder is 30 mu m, and pumping the vacuum degree of a spheroidizing cavity to 7 multiplied by 10-2Under Pa, flowing argon gas is filled as a protective atmosphere.
Secondly, after the air pressure is stable, starting an atomization process: the equiaxial powder is delivered to a working area of radio frequency high temperature plasma by a powder delivery probe, is melted by high temperature and is delivered to a cooling part, and liquid drops are spheroidized into spherical solid particles by gas cooling.
In this step: the atomization air inlet pressure is adjusted to be 0.3-0.5MPa, the atomization temperature is about 800-.
Thirdly, the spherical solid particles are sequentially sieved by a multi-stage screen with the particle size of 120 mu m, 53 mu m and 18 mu m.
Fourthly, the powder with the particle size distribution of 18 to 53 mu m after being screened enters a bismuth telluride-based spherical powder collecting barrel, and the powder with the particle size distribution of 18 to 53 mu m is repeatedly atomized and screened.
Fifthly, obtaining the bismuth telluride-based spherical powder precursor with the powder yield of 30 percent.
The working principle of the embodiment is schematically shown in fig. 1, a raw material, such as axial powder 1, enters a plasma spheroidizing region 4 from a feed inlet 2 to be melted, cooled and spheroidized into spheroidized powder 5, and high-purity argon gas 3 is used as a protective atmosphere.
Example 2
A method for preparing bismuth telluride based spherical powder comprises the following steps:
preparing commercial isometric powder of p-type (or n-type) bismuth telluride-based thermoelectric material, wherein the average particle size of the powder is 30 mu m, and pumping the vacuum degree of a spheroidizing cavity to 7 multiplied by 10-2Under Pa, flowing argon gas is filled as a protective atmosphere.
Secondly, after the air pressure is stable, starting an atomization process: the equiaxial powder is delivered to a working area of radio frequency high temperature plasma by a powder delivery probe, is melted by high temperature and is delivered to a cooling part, and liquid drops are spheroidized into spherical solid particles by gas cooling.
In the step: the atomization air inlet pressure is adjusted to be 0.1-0.25MPa, the atomization temperature is about 500-700 ℃, the working voltage is set to be 4.5KV, the powder feeding speed is 45g/min, the carrier gas flow is 4.5L/min, and the aperture of the argon nozzle is 3-5 mm.
Thirdly, the spherical solid particles are sequentially sieved by a multi-stage screen with the particle size of 120 mu m, 53 mu m and 18 mu m.
Fourthly, the powder with the particle size distribution of 18 to 53 mu m enters a bismuth telluride-based spherical powder collecting barrel, and the powder with the particle size distribution of 18 to 53 mu m is repeatedly atomized and sieved again.
Fifthly, obtaining the bismuth telluride-based spherical powder precursor with the powder yield of 22 percent.
The working principle of the embodiment is schematically shown in fig. 1, a raw material, such as axial powder 1, enters a plasma spheroidizing region 4 from a feed inlet 2 to be melted, cooled and spheroidized into spheroidized powder 5, and high-purity argon gas 3 is used as a protective atmosphere.
Example 3
A method for preparing bismuth telluride based spherical powder comprises the following steps:
preparing commercial isometric powder of p-type (or n-type) bismuth telluride-based thermoelectric material, wherein the average particle size of the powder is 30 mu m, and pumping the vacuum degree of a spheroidizing cavity to 7 multiplied by 10-2Under Pa, flowing argon gas is filled as a protective atmosphere.
Secondly, after the air pressure is stable, starting an atomization process: the equiaxial powder is delivered to a working area of radio frequency high temperature plasma by a powder delivery probe, is melted by high temperature and is delivered to a cooling part, and liquid drops are spheroidized into spherical solid particles by gas cooling.
In this step: the atomization air inlet pressure is adjusted to be 0.6-0.9MPa, the atomization temperature is about 1100-.
Thirdly, the spherical solid particles are sequentially sieved by a multi-stage screen with the particle size of 120 mu m, 53 mu m and 18 mu m.
Fourthly, the powder with the particle size distribution of 18 to 53 mu m after being screened enters a bismuth telluride-based spherical powder collecting barrel, and the powder with the particle size distribution of 18 to 53 mu m is repeatedly atomized and screened.
Fifthly, obtaining the bismuth telluride-based spherical powder precursor with the powder yield of 18 percent.
The working principle of the embodiment is schematically shown in fig. 1, a raw material, such as axial powder 1, enters a plasma spheroidizing region 4 from a feed inlet 2 to be melted, cooled and spheroidized into spheroidized powder 5, and high-purity argon gas 3 is used as a protective atmosphere.
Example 4
The results of testing the bismuth telluride-based spherical powder prepared in examples 1 to 3 are shown in fig. 2 to 5, wherein fig. 2 and 3 are graphs of the morphology of the spherical powder observed by a scanning electron microscope. Fig. 4 and 5 are graphs showing the dependence of volume fraction (left y-axis)/cumulative percentage (right y-axis) of p-type and n-type spherical powders on the particle size of the powders.
As can be seen from FIGS. 2 and 3, no obvious satellite impurity powder is found on the surface of the spheroidized powder, and the laser particle size analysis results are shown in FIGS. 4 and 5, which show that the particle size distribution of the spheroidized powder is mostly distributed in the range of 10-53 μm, and the test results show that the spherical powder meets the requirements of the subsequent SLM printing process.
The bismuth telluride-based spherical powders prepared in examples 1 to 3 were subjected to hall flow rate and tap density tests, respectively, with the hall flow rate results shown in table 1 below and the tap density results shown in table 2 below.
TABLE 1
| Model number | Sample No. 1 (S) | Sample No. 2 (S) | Sample No. 3 (S) | Sample No. 4 (S) | Sample No. 5 (S) |
| p | 12.44 | 12.96 | 13.78 | 13.26 | 13.32 |
| n | 12.85 | 12.63 | 13.12 | 13.21 | 12.96 |
TABLE 2
Example 5
A preparation method of a print of a bismuth telluride based thermoelectric material comprises the following steps:
firstly, a printing substrate is arranged in a forming bin of the SLM system, and the surface of the printing substrate is ensured to be parallel to the horizontal plane of the forming bin as much as possible by means of a level meter.
The SLM system is provided with a fiber laser (the laser wavelength is 1064nm, the maximum power of the laser is 100W), a powder laying system, a numerical control forming bin and a protective atmosphere control system.
② the bismuth telluride based spherical precursor powder with the grain size distribution of 18-53 μm prepared in the embodiment 1-3 is loaded into a powder storage bin.
Thirdly, closing the cabin door of the system, introducing flowing high-purity argon (with the purity of 99.999 percent), and setting the ventilation volume to be 10-15L/min, thereby reducing the oxygen partial pressure value in the cavity.
And fourthly, when the integral oxygen partial pressure value is lower than 200ppm, performing SLM printing.
The printing parameters are as follows: laser power is 10-40W, scanning speed is 400-600mm/s, scanning interval is 50 μm, and powder layer thickness is 30 μm.
And fifthly, obtaining the printed product of the bismuth telluride-based thermoelectric material.
The working principle of the embodiment is schematically shown in fig. 6, and in fig. 6, a laser beam 1 is converted into a laser beam 2, and bismuth telluride-based spherical precursor powder is printed on a printing substrate 4 to form a powder layer 3.
Example 6
And 7, detecting the printed bismuth telluride-based printed product in the embodiment 5, and taking structural and phase information and basic morphology diagrams of the bismuth telluride-based printed sample as shown in fig. 7 to 10. 7-8 show appearance and appearance of a square piece and an arc piece of SLM printing respectively; fig. 9 and 10 are X-ray diffraction (XRD) images of SLM printed samples (parallel and perpendicular build directions).
Fig. 6-7 show that the SLM can be used to print and shape the bismuth telluride-based thermoelectric material smoothly, and the archimedes drainage method shows that the relative mass density of the printed sample reaches 97.5%, which is comparable to the density of the sample using the conventional sintering process. The SLM technology 3D printing of the bismuth telluride-based thermoelectric material is carried out by using an industrial standard production route, the spherical powder is used as precursor powder to meet the technical requirements of the SLM, the rapid integrated forming is realized, the density of a printed formed part is high, and the SLM technology is suitable for standard commercial production and popularization of the bismuth telluride-based thermoelectric material and devices. Successful printing of the arc-shaped part can meet the requirement of being used for laminating certain curved surface heat sources, so that the use efficiency of the curved surface heat sources is improved, and the energy conversion efficiency of the thermoelectric device is further increased. Figure 8 shows that X-ray diffraction (XRD) characterization of SLM prints, comparison of the printed samples with standard bismuth telluride based XRD diffractograms revealed no presence of a hetero-phase, indicating that pure phase samples were obtained. The high intensity diffraction peak found parallel to the sample build direction (110) means that there is texture orientation inside the sample due to the extremely fast cooling rate (10) during SLM printing3-108C/s) results from non-equilibrium coagulation.
Example 7
The printed material of the bismuth telluride-based thermoelectric material of example 5 was subjected to vacuum annealing with the degree of vacuum set to 10-3Pa, setting the annealing temperature to 400 ℃ and the annealing time to 24h to obtain the annealed bismuth telluride base thermoelectric material printing piece.
Example 8
The printed material of the bismuth telluride-based thermoelectric material of example 5 and the printed material of the annealed bismuth telluride-based thermoelectric material of example 7 were subjected to thermoelectric performance tests, respectively. Fig. 11 to 18 are graphs showing the dependence of thermoelectric properties in the parallel build direction and the perpendicular build direction of the printed matter of the bismuth telluride-based thermoelectric material of example 5 and the printed matter of the annealed bismuth telluride-based thermoelectric material of example 7 on temperature, wherein fig. 11 and 15 are p-type and n-type conductivities; FIGS. 12 and 16 show the p-type and n-type Seebeck coefficients; fig. 13 and 17 are p-type and n-type total thermal conductivities; FIGS. 14-18 show p-type and n-type thermoelectric figure of merit (ZT).
Fig. 12 and 15 show that the conductivity is significantly anisotropic, and the conductivity of the electron transported in the parallel building direction of the original sample and the annealed sample is higher than that in the vertical building direction, which results in higher conductivity in the parallel building direction than in the vertical building direction because electrons are more strongly scattered in the texture than outside the texture. However, the conductivity of the annealed sample in the parallel building direction is lower than that of the original sample in the parallel building direction, which is likely to be due to an increase in the mobility of carriers due to a decrease in the number of grain boundaries of the annealed sample, and a decrease in the carrier concentration of the sample, resulting in a decrease in the conductivity. Fig. 12 and 16 show that the Seebeck coefficient is slightly different between the original printed sample and the annealed sample in the two construction directions, but the Seebeck coefficient of the annealed sample is higher than that of the original printed sample, and the main reason is that partial inversion defects are eliminated after annealing, so that the Seebeck coefficient is improved. Fig. 13 and 17 also exhibit typical anisotropy, resulting in lower thermal conductivity perpendicular to the build direction than parallel to the build direction, due to lower phonon scattering in the parallel build direction than perpendicular to the build direction. Furthermore, the thermal conductivity of the annealed samples was lower than the original printed samples in both build directions, the main reason for this being that the electron thermal conductivity contribution is reduced due to the reduced electron concentration. The calculated thermoelectric figure of merit (ZT) for the as-printed and annealed samples of fig. 14 and 18 show that the p-type as-printed sample has a lower thermoelectric figure of merit, with thermoelectric figures of merit in the parallel build direction and the perpendicular build direction of 0.66 and 0.21, respectively, whereas the annealed samples have greatly improved thermoelectric figures of merit in both directions, 1.29 and 0.68, respectively. Similarly, the thermoelectric figure of merit for the n-type raw print sample was low, with thermoelectric figures of merit in the parallel build direction and the perpendicular build direction of 0.24 and 0.12, respectively, whereas the thermoelectric figures of merit for the annealed samples were greatly improved in both directions, 0.94 and 0.676, respectively. The thermoelectric figure of merit ZT can intuitively reflect the thermoelectric conversion capability of the sample, the thermoelectric figure of merit of the annealed sample is superior to that of the commercialized bismuth telluride-based thermoelectric material, and the material obtained by printing is proved to have commercial utilization value.
Example 9 molten pool control experiment
Firstly, a printing substrate is arranged in a forming bin of the SLM system, and the surface of the printing substrate is ensured to be parallel to the horizontal plane of the forming bin as much as possible by means of a level meter.
The SLM system is provided with a fiber laser (the laser wavelength is 1064nm, the maximum power of the laser is 100W), a powder laying system, a numerical control forming bin and a protective atmosphere control system.
② the bismuth telluride-based spherical precursor powder with the particle size distribution of 18-53 μm prepared in the example 1-3 is loaded into a powder storage bin.
Thirdly, closing the cabin door of the system, introducing flowing high-purity argon (with the purity of 99.999 percent), and setting the ventilation volume to be 10-15L/min, thereby reducing the oxygen partial pressure value in the cavity.
And fourthly, when the integral oxygen partial pressure value is lower than 200ppm, SLM printing with different printing parameters is carried out.
The molten pool is shown in FIG. 21, wherein:
the printing parameters in FIG. 21(a) were 10W of laser power, 300mm/s of scanning rate, 50 μm of scanning pitch, and 30 μm of powder coating thickness.
The printing parameters in FIG. 21(b) were 20W of laser power, 500mm/s of scanning speed, 50 μm of scanning pitch, and 30 μm of powder coating thickness.
The printing parameters in FIG. 21(c) were 40W of laser power, 500mm/s of scanning speed, 50 μm of scanning pitch, and 30 μm of powder coating thickness.
The printing parameters in FIG. 21(d) were laser power 60W, scanning rate 300mm/s, scanning pitch 50 μm, and powder coating thickness 30 μm.
The printing parameters in FIG. 21(e) were 70W of laser power, 300mm/s of scanning speed, 50 μm of scanning pitch, and 30 μm of powder bed thickness.
The printing parameters of FIG. 21(f) were laser power 190W, scanning rate 300mm/s, scanning pitch 50 μm, and powder coat thickness 30 μm.
Comparative example 1
A printed product was prepared by using the method and parameters of example 5 using the same equiaxed powder (the same as the raw material of example 1, and the equiaxed powder is observed by scanning electron microscopy on spherical powder morphology figures shown in fig. 19 and 20) of a commercial p-type (or n-type) bismuth telluride-based thermoelectric material, and the final molded product could not be printed successfully because the equiaxed powder has poor fluidity and could not be spread smoothly in the experiment.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (5)
1. Precursor powder of a 3D printing piece of a bismuth telluride-based thermoelectric material is characterized in that the precursor powder of the 3D printing piece of the bismuth telluride-based thermoelectric material is powder prepared by carrying out gas atomization on isometric powder of a p-type or n-type bismuth telluride-based thermoelectric material.
2. A method for preparing precursor powder of a 3D print of the bismuth telluride-based thermoelectric material as set forth in claim 1, comprising the steps of:
vacuumizing an atomization cavity, and filling flowing argon as a protective atmosphere;
secondly, atomization: sending the equiaxial powder of bismuth telluride to a working area of radio frequency high-temperature plasma, melting the equiaxial powder, cooling, and spheroidizing into spherical solid particles; the atomization air inlet pressure is 0.1-0.6MPa, the atomization temperature is 700-;
thirdly, screening the spherical solid particles into powder with the particle size distribution of 10-60 mu m and powder with the particle size distribution of 10-60 mu m;
fourthly, the powder with the particle size distribution outside 10 to 60 mu m is repeatedly atomized and sieved again, and the particle size distribution enters the fifth step when the particle size distribution is 10 to 60 mu m;
obtaining precursor powder.
3. The method for preparing the precursor powder of the 3D printing piece of the bismuth telluride-based thermoelectric material as claimed in claim 2, wherein the degree of vacuum is 7 x 10-2Pa or less.
4. The method for preparing the precursor powder of the 3D printing piece of the bismuth telluride-based thermoelectric material according to any one of claims 2 to 3, wherein the sieving screen is a multistage screen.
5. The method for preparing the precursor powder of the 3D printing piece of the bismuth telluride-based thermoelectric material according to claim 4, wherein the multistage screens are 120 μm, 53 μm and 18 μm multistage screens.
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