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CN-121976070-A - Rare earth-based half heusler alloy material, and preparation method and application thereof

CN121976070ACN 121976070 ACN121976070 ACN 121976070ACN-121976070-A

Abstract

The invention discloses a rare earth-based half heusler alloy material, a preparation method and application thereof, wherein the preparation method comprises the steps of smelting Pt and Sb metal raw materials to obtain a precursor PtSb, smelting Lu and Re metal raw materials and the precursor PtSb for the second time to obtain a smelting cast ingot, crushing, ball milling and sintering to obtain the rare earth-based half heusler alloy material Lu 1‑x Re x PtSb, wherein Re=Sc or Y, x represents atomic percentage, and x is more than or equal to 0 and less than or equal to 1.0. The invention takes scandium, yttrium, lutetium, platinum and antimony as raw materials, and the ingot is obtained through a suspension smelting reaction by a two-step method, the method can control the intensity of thermochemical reaction, and avoid a large amount of heat released at one time instant of feeding, thereby obtaining a high-quality rare earth-based half heusler alloy material, and the optimal peak thermoelectric figure of merit can reach more than 1.0 and exceed the highest level reported in the prior art.

Inventors

  • FU CHENGUANG
  • MIAO PU
  • ZHU TIEJUN

Assignees

  • 浙江大学

Dates

Publication Date
20260505
Application Date
20260128

Claims (10)

  1. 1. A preparation method of a rare earth-based half heusler alloy material is characterized by comprising the steps of smelting Pt and Sb metal raw materials to obtain a precursor PtSb, smelting Lu and Re metal raw materials and the precursor PtSb for the second time to obtain a smelting cast ingot, crushing and ball milling, and sintering to obtain the rare earth-based half heusler alloy material Lu 1-x Re x PtSb, wherein Re=Sc or Y, and x represents atomic percentage, and x is more than or equal to 0 and less than or equal to 1.0.
  2. 2. The method for producing a rare earth-based half heusler alloy material according to claim 1, wherein the melting is performed by a suspension melting method.
  3. 3. The method for producing a rare earth-based half heusler alloy material according to claim 1, wherein the melting is performed in an inert gas atmosphere, and the relative gas pressure in the quartz tube before the melting is started is not higher than 0.02MPa.
  4. 4. The method for producing a rare earth-based half heusler alloy material according to claim 1, wherein the sintering is a plasma discharge sintering, and the sintering process is 10-20 min sintering at 850-950 ℃ and 80-100 MPa.
  5. 5. A class of rare earth-based half heusler alloy materials produced according to the method of any one of claims 1-4, wherein the rare earth-based half heusler alloy materials have a peak thermoelectric figure of merit of 0.65 or greater.
  6. 6. The rare earth-based half heusler alloy material according to claim 5, wherein the rare earth-based half heusler alloy material has a peak thermoelectric figure of merit of 0.8 or more; When Re=Sc, x is more than or equal to 0.5 and less than or equal to 0.9; when re=y, the number of the elements is, x is more than or equal to 0.5 and less than or equal to 1.
  7. 7. The rare earth-based half heusler alloy material according to claim 5, wherein the rare earth-based half heusler alloy material has a peak thermoelectric figure of merit of 1.0 or more.
  8. 8. The rare earth-based half heusler alloy material according to claim 7, wherein when re=sc, 0.5+.x+.0.7; when re=y, the number of the elements is, x is more than or equal to 0.5 and less than or equal to 0.75.
  9. 9. The rare earth-based half heusler alloy material according to claim 5, wherein the rare earth-based half heusler alloy material is Lu 0.4 Sc 0.6 PtSb or Lu 0.3 Y 0.7 PtSb.
  10. 10. Use of the rare earth-based half heusler alloy material according to any one of claims 5-9 as a thermoelectric material.

Description

Rare earth-based half heusler alloy material, and preparation method and application thereof Technical Field The invention relates to the technical field of thermoelectric materials, in particular to a rare earth-based half heusler alloy material, and a preparation method and application thereof. Background Thermoelectric effects enable direct interconversion of electrical and thermal energy through the movement of charge carriers (electrons or holes) within the material. When there is a temperature difference across the thermoelectric material, the thermoelectric material can convert thermal energy to electrical energy for output. The power generation device manufactured by the thermoelectric material can be used as a power supply for deep space spacecrafts, field operations, ocean lighthouses and nomadic people, or used for industrial waste heat and waste heat power generation. Thermoelectric materials for use in high performance thermoelectric devices should have high electrical conductivityAnd a thermoelectric coefficient S and low thermal conductivity。 The half heusler alloy material is a large class of intermetallic compounds with a composition of XYZ and a crystallographic space group of No. 216, wherein X, Y and Z are all metal elements, and each element occupies a set of face-centered cubic sub-lattices. The sum of the number of electrons at the outermost layer of each element meets the 18-electron rule, and is a semiconductor material with a narrow band gap. The types of half heusler alloy materials currently under investigation are very limited, and are substantially developed around MNiSn, MCoSb, RFeSb or other components that do not contain rare earth elements, where m=ti, zr, hf, r=v, nb, ta, an interfacial barrier for half heusler alloy thermoelectric materials such as disclosed in CN 111211214A, which comprises a variety of non-rare earth based half heusler alloys that are currently common. Non-rare earth-based half heusler alloy materials tend to exhibit higher intrinsic lattice thermal conductivities, which are major obstacles to further enhancement of their thermoelectric properties. The rare earth-based half heusler alloys have a huge number ratio in the family of half heusler alloys and lower intrinsic lattice thermal conductivity. However, rare earth-based half heusler alloy materials are very rarely studied, high-quality polycrystalline samples are difficult to prepare, and the thermoelectric performance is poor and far from that of a classical non-rare earth-based half heusler thermoelectric material. CN106170875A discloses a material for thermoelectric energy conversion, which is a P-type half heusler compound, including YNiSb, YNiBi, laNiSb and lanbi, and exemplifies the replacement of yttrium or lanthanum components with alkaline earth magnesium, but the relevant properties and data of the corresponding rare earth-based half heusler alloy material are not disclosed in the practical application process. Li et al (Li, G., Kurosaki, K., Ohishi, Y., Muta, H. & Yamanaka, S. High Temperature Thermoelectric Properties of Half-Heusler Compound PtYSb. Jpn. J. Appl. Phys. 52, 041804 (2013)) have used a solid phase reaction method in combination with a plasma spark sintering to prepare a YPtSb polycrystalline sample, however, the sample has a small amount of second phase and a peak thermoelectric figure of merit of less than 0.6, which is far inferior to the thermoelectric performance of classical half heusler alloy materials. This illustrates the challenges that rare earth-based half heusler alloy materials present in high quality polycrystalline sample preparation. Disclosure of Invention Aiming at the problems of difficult preparation and poor thermoelectric performance of high-quality polycrystalline samples existing in rare earth-based half heusler alloy in the prior art, the invention provides a preparation method applicable to rare earth-based half heusler alloy materials, which can prepare a high-quality rare earth-based half heusler polycrystalline material, and has excellent performance in thermoelectric application, and the highest thermoelectric figure of merit can reach more than 1.0. In order to achieve the above purpose, the invention adopts the following technical scheme: A preparation method of a rare earth-based half heusler alloy material comprises the steps of smelting Pt and Sb metal raw materials to obtain a precursor PtSb, smelting Lu and Re metal raw materials and the precursor PtSb for the second time to obtain a smelting cast ingot, crushing and ball milling, and sintering to obtain the rare earth-based half heusler alloy material Lu 1-xRex PtSb, wherein Re=Sc or Y, x represents atomic percentage, and x is more than or equal to 0 and less than or equal to 1.0. Compared with the conventional half heusler compound, the rare earth-based half heusler alloy material with high thermoelectric performance has larger electronegativity difference of element composition, relea