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CN-121976300-A - Dysprosium-based half heusler polycrystalline material and preparation method and application thereof

CN121976300ACN 121976300 ACN121976300 ACN 121976300ACN-121976300-A

Abstract

The invention discloses a dysprosium-based half heusler polycrystalline material, a preparation method and application thereof, wherein the chemical formula of the polycrystalline material is Dy 1‑x Y x Pt 1‑y Ni y Sb, x and Y are atom percentages, x is more than or equal to 0 and less than or equal to 1.0, Y is more than or equal to 0 and less than or equal to 0.4, the preparation method comprises the steps of weighing metal raw materials according to the stoichiometric ratio of Dy 1‑x Y x Pt 1‑y Ni y Sb, mixing Pt, ni and Sb, smelting to obtain a precursor Pt 1‑y Ni y Sb, smelting Dy and Y metal raw materials and the precursor Pt 1‑ y Ni y Sb for the second time to obtain a smelting cast ingot, crushing, ball milling and sintering to obtain the polycrystalline material. The material is composed of dysprosium and yttrium serving as main rare earth elements and Pt and Sb elements, and the peak thermoelectric figure of merit and the average thermoelectric figure of merit are obviously improved through the regulation and control of the component content and the double-layer synergistic effect of the preparation method, and the highest thermoelectric figure of merit can reach 1.33.

Inventors

  • FU CHENGUANG
  • MIAO PU
  • ZHU TIEJUN

Assignees

  • 浙江大学

Dates

Publication Date
20260505
Application Date
20260128

Claims (10)

  1. 1. The dysprosium-based half heusler polycrystalline material is characterized in that the chemical formula of the polycrystalline material is Dy 1-x Y x Pt 1- y Ni y Sb, wherein x and y represent atomic percentages, x is more than or equal to 0 and less than or equal to 1.0, and y is more than or equal to 0 and less than or equal to 0.4; The preparation method of the polycrystalline material comprises the steps of weighing metal raw materials according to the stoichiometric ratio of Dy 1-x Y x Pt 1-y Ni y Sb, mixing Pt, ni and Sb, smelting to obtain a precursor Pt 1-y Ni y Sb, secondarily smelting Dy and Y metal raw materials and the precursor Pt 1-y Ni y Sb to obtain a smelting cast ingot, crushing, ball milling and sintering to obtain the polycrystalline material.
  2. 2. The dysprosium-based half heusler polycrystalline material of claim 1 wherein said smelting is by a suspension smelting process.
  3. 3. The dysprosium-based half heusler polycrystalline material of claim 1 wherein said smelting is carried out in an inert gas atmosphere, preferably a relative gas pressure of no more than 0.02MPa in the quartz tube prior to onset of smelting.
  4. 4. The dysprosium-based half heusler polycrystalline material of claim 1, wherein the sintering is a plasma discharge sintering and the sintering process is sintering at 850-950 ℃ and 80-100 MPa ℃ for 10-20 min.
  5. 5. The dysprosium-based half heusler polycrystalline material of claim 1 wherein said polycrystalline material has a peak thermoelectric figure of merit of greater than 0.8.
  6. 6. The dysprosium-based half heusler polycrystalline material of claim 1, wherein 0≤x≤0.8 and 0≤y≤0.4.
  7. 7. The dysprosium-based half heusler polycrystalline material of claim 1 wherein said polycrystalline material has a peak thermoelectric figure of merit of 1.0 or greater.
  8. 8. The dysprosium-based half heusler polycrystalline material of claim 1, wherein 0≤x≤0.5 and 0≤y≤0.4.
  9. 9. The method for preparing the dysprosium-based half heusler polycrystalline material according to any one of claims 1-8, characterized in that metal raw materials are weighed according to the stoichiometric ratio of Dy 1-x Y x Pt 1-y Ni y Sb in the raw material composition, pt, ni and Sb are mixed and then smelted to obtain a precursor Pt 1-y Ni y Sb, dy and Y metal raw materials and the precursor Pt 1-y Ni y Sb are smelted for the second time to obtain a smelting ingot, and the smelting ingot is sintered to obtain the polycrystalline material Dy 1-x Y x Pt 1-y Ni y Sb after crushing and ball milling.
  10. 10. Use of the dysprosium-based half heusler polycrystalline material according to any of claims 1-8 as thermoelectric material.

Description

Dysprosium-based half heusler polycrystalline material and preparation method and application thereof Technical Field The invention relates to the technical field of thermoelectric materials, in particular to a dysprosium-based semi-heusler polycrystalline material, and a preparation method and application thereof. Background The material of the thermoelectric generator or thermoelectric cooler is called thermoelectric material, and is a material capable of realizing the alternating conversion of electric energy and heat energy. The thermoelectric power generation and refrigeration device made of thermoelectric materials has the advantages of no pollution, no noise, easy maintenance, safety, reliability and the like. The performance of a thermoelectric material is represented by the thermoelectric figure of merit ZT, which is defined as z=s2σ/κ. Whereas ZT is determined by three mutually constrained factors of electrical conductivity σ, seebeck coefficient S and thermal conductivity κ. Although the thermoelectric generation and semiconductor refrigeration technology has the advantages which are incomparable with the traditional technology, the defect of low thermoelectric conversion efficiency greatly restricts the wide application of the technology, and the breakthrough progress of the technology really depends on the great improvement of the performance of thermoelectric materials. Half heusler alloy materials are a class of ternary intermetallic compounds with a chemical formula of ABX, a crystal space group of F-43m (No. 216), which can be regarded as B atoms filling in tetrahedral interstices of which AX constitutes half of the rock salt structure. When the total number of electrons of the outermost layer of the element is 18, the material will exhibit semiconductor transport characteristics. Current research into 18-electron half heusler compounds is limited to non-rare earth based half heusler compounds, such as MNiSn, MCoSb, RFeSb, where m=ti, zr, hf, r=v, nb, ta. CN101197420a discloses a rare earth doped Mg 2 Si based thermoelectric material, which is to use rare earth for doping to improve thermoelectric performance of the material. Directly adding rare earth during smelting, mechanically ball-milling the smelted material, and hot-pressing to obtain the bulk thermoelectric material of Mg 2-xSiREx, wherein RE represents rare earth elements, and x=0.002-0.01. The thermoelectric performance of the material is improved by doping the rare earth metal, but the doping amount of the rare earth metal is smaller and still stays in the type of thermoelectric material which is not rare earth-based. Rare earth-based half heusler alloy materials are very rare in research, high-quality polycrystalline samples are difficult to prepare, and the thermoelectric performance is poor and far inferior to that of a classical non-rare earth-based half heusler thermoelectric material. CN110760933A discloses a preparation method of a rare earth telluride-based high-temperature thermoelectric material, wherein the chemical formula of the rare earth telluride-based high-temperature thermoelectric material is Re 3-xTe4, x is more than or equal to 0 and less than or equal to 0.33, re is a rare earth element, the preparation method of the rare earth telluride-based high-temperature thermoelectric material comprises the steps of (1) weighing and mixing Re simple substance blocks and Te simple substance blocks serving as raw materials according to the chemical formula of the rare earth telluride-based high-temperature thermoelectric material to obtain mixed blocks, (2) heating the obtained mixed blocks at 900-1300 ℃ until melting is achieved, then cooling to room temperature to obtain a molten block material, and (3) ball milling the obtained molten block material under a protective atmosphere to obtain the rare earth telluride-based high-temperature thermoelectric material, wherein the ball milling speed is 600-1500 revolutions per minute, and the ball milling total time is 3-24 hours. The invention combines the premelting and ball milling process, can rapidly realize the synthesis of single pure phase in a short time, and reduces the probability of introducing impurities during ball milling, so that the final ZT value of the material is improved, and the maximum ZT value reaches more than 1.0 at 1000K and is improved by more than 20 percent compared with the traditional process. But the compound does not belong to the half heusler alloy material. Disclosure of Invention Aiming at the problems of insufficient research and poor thermoelectric performance of rare earth-based half heusler alloy, the invention provides a dysprosium-based half heusler polycrystalline material which is composed of dysprosium and yttrium serving as main rare earth elements matched with Pt and Sb elements to obtain a polycrystalline material with excellent thermoelectric performance, the highest thermoelectric figure of merit can reach 1.33, In order to