CN-121972666-A - Fe-Cr-based multi-element alloy barrier layer of PbTe-based thermoelectric material, and preparation method and application thereof

Abstract

S1, weighing raw materials according to chemical proportion, obtaining corresponding cast ingots through a smelting process and annealing, and crushing and grinding the cast ingots into fine powder to obtain Pb-Te powder and Sn-Te powder; S2, weighing raw materials according to a chemical formula, preparing a Fe-Cr-based multi-element alloy block by adopting an alloying method, obtaining an alloy ingot by adopting a smelting process, crushing and grinding the alloy ingot into fine powder to obtain Fe-Cr-based multi-element alloy powder, and S3, sequentially filling PbTe powder, snTe powder and Fe-Cr-based multi-element alloy powder into a graphite mold, and obtaining a compact Pb-Te/Sn-Te/Fe-Cr-based multi-element alloy composite block by spark plasma sintering to complete the preparation of the Fe-Cr-based multi-element alloy barrier layer. The barrier layer has good thermal expansion matching and high interface stability.

Inventors

• JIANG JUN
• TAN XIAOJIAN
• Fan Lianghan
• ZHANG ZONGWEI
• ZHANG QIANG
• CAI JIANFENG

Assignees

• 中国科学院宁波材料技术与工程研究所

Dates

Publication Date

20260505

Application Date

20251217

Claims (10)

1. 1. The preparation method of the Fe-Cr-based multi-element alloy barrier layer of the PbTe-based thermoelectric material is characterized by comprising the following steps of: S1, weighing raw materials according to the chemical proportion of Pb-Te based alloy and the chemical proportion of Sn-Te based alloy, respectively obtaining corresponding cast ingots through a smelting process and annealing, and crushing and grinding into fine powder to obtain Pb-Te alloy powder and Sn-Te alloy powder; s2, weighing raw materials according to the chemical proportion of the Fe-Cr-based multi-element alloy, preparing an Fe-Cr-based multi-element alloy block by adopting an alloying method, obtaining an alloy ingot by adopting a smelting process, and crushing and grinding the alloy ingot into fine powder to obtain Fe-Cr-based multi-element alloy powder; S3, sequentially filling Pb-Te alloy powder, sn-Te alloy powder and Fe-Cr-based multi-element alloy powder into a graphite mold, and obtaining a compact Pb-Te/Sn-Te/Fe-Cr-based multi-element alloy composite block body through a spark plasma sintering process, thereby completing the preparation of the Fe-Cr-based multi-element alloy barrier layer.
2. 2. The method of claim 1, wherein the Fe-Cr-based multi-component alloy comprises Fe x Cr y Ni z 、Fe x Cr y Co z 、Fe x Cr y Al z 、Fe x Co y Ni z Cr r 、Fe x Cr y Ni z Al r , wherein in the ternary alloy x: y: z is (2-5): (2-5), and in the quaternary alloy x: y: z: r is (1-4): (1-4); And/or the chemical formula of the Pb-Te-based alloy is Pb 1-m TeM m , the doping element M is at least one of Na, K, ag, sb, bi, cu, mg, se, I, br, al, sb, bi, in and Cd, and the doping content M is 0.1-10%; And/or the chemical formula of the Sn-Te based alloy is Sn 1-n TeN n , the doping element N is selected from at least one of I, br, na, K, ag, mn, mg, cd or In, the doping content N is 0.1% -10%, or the doping element N is selected from at least one of Sb, bi or Pb, and the doping content N is 0.1% -30%.
3. 3. The preparation method of claim 1, wherein step S1 is to weigh high purity raw materials according to the chemical proportion of Pb-Te-based alloy and Sn-Te-based alloy, put the raw materials into a quartz tube, vacuum-pack the raw materials, heat the raw materials to 1350-1500K for melting and preserving heat for 5-40 h, quench the raw materials, anneal the raw materials at 800-1000K for 40-80 h to obtain ingots with uniform components, and crush the ingots into fine powder to obtain Pb-Te alloy powder and Sn-Te alloy powder respectively.
4. 4. The preparation method of claim 1, wherein step S2 is to weigh raw materials of high purity Fe, cr and other elements according to a chemical proportion, put the raw materials into a quartz tube, vacuum-pack the raw materials, heat the raw materials to be melted at a high temperature, heat-preserving the cold extract the raw materials, anneal the raw materials to obtain ingots with uniform components, and crush the ingots into fine powder to obtain the Fe-Cr-based multi-element alloy powder.
5. 5. The preparation method according to claim 1, wherein step S3 is to sequentially fill Pb-Te alloy powder, sn-Te alloy powder and Fe-Cr based multi-element alloy powder into a graphite mold, apply uniaxial pressure of 30-60 MPa to the filled mold by spark plasma sintering under inert atmosphere or vacuum condition, heat to 800-950K, and keep the temperature for 10-30 min, to obtain a compact Pb-Te/Sn-Te/Fe-Cr based multi-element alloy composite block.
6. 6. The method according to claim 3 or 4, wherein the obtained Pb-Te alloy powder, sn-Te alloy powder and Fe-Cr-based multi-element alloy powder have a particle size distribution in the range of 10 to 100. Mu.m.
7. 7. A PbTe-based thermoelectric material Fe-Cr-based multi-element alloy barrier layer, characterized by being prepared by the preparation method according to any one of claims 1 to 6.
8. 8. Use of a PbTe-based thermoelectric material Fe-Cr-based multi-element alloy barrier layer as claimed in claim 7 in a thermoelectric device, wherein the obtained Pb-Te/Sn-Te/Fe-Cr-based multi-element alloy composite block is nickel-plated on both end surfaces thereof to be used as a thermoelectric element, wherein one end of the Fe-Cr-based multi-element alloy barrier layer is used as a high temperature end of the thermoelectric element and the other end of the Pb-Te-based alloy is used as a low temperature end of the thermoelectric element.
9. 9. The use according to claim 8, wherein the nickel plating of the two end surfaces of the Pb-Te/Sn-Te/Fe-Cr based multi-element alloy composite block is performed by immersing the Pb-Te/Sn-Te/Fe-Cr based multi-element alloy composite block in an electroplating solution containing Ni (NH 2 SO 3 ) 2 、NiC1·6H 2 O、H 3 BO 3 and a solvent) as a cathode and a simple substance nickel plate as an anode, and electroplating at a temperature of 313-318K for 20-40 min.
10. 10. The use of claim 8, wherein the wires of the thermoelectric device are connected to the Fe-Cr based multi-element alloy barrier layer by snpbg solder at the high temperature end and to the Pb-Te base end by snpbi solder at the low temperature end.

Description

Fe-Cr-based multi-element alloy barrier layer of PbTe-based thermoelectric material, and preparation method and application thereof Technical Field The invention relates to the technical field of thermoelectric materials and thermoelectric devices, in particular to a Fe-Cr-based multi-element alloy barrier layer of a PbTe-based thermoelectric material, and a preparation method and application thereof. Background Thermoelectric power generation devices based on the Seebeck effect can directly convert thermal energy into electrical energy. Wherein, pbTe has both high thermoelectric performance and good chemical stability in the temperature range of 600-800K, and is considered as one of the most representative thermoelectric materials in the medium temperature range. Meanwhile, the power generation device prepared by the method is successfully applied to the fields of Radioisotope Thermoelectric Generators (RTGs) of deep space detectors, deep ultraviolet LED heat dissipation, precise temperature control and the like, and extremely high reliability of the power generation device is fully verified. In practice, the performance of thermoelectric devices depends not only on the zT of the bulk material, but also on the interfacial stability, contact resistance, and thermo-mechanical matching between the electrode, diffusion barrier (TEiM), and thermoelectric material. Fe is commonly used as an interface material in conventional PbTe-based devices, where Fe has a low diffusion coefficient and a low interface resistance, but there is a significant mismatch in thermal expansion coefficients between PbTe (linear expansion coefficient of about 20×10 -6K-1) and Fe (about 15×10 -6K-1), and long-term thermal cycling or high Wen Fuyi tends to accumulate thermal stress at the interface, causing cracks and holes to increase in interface resistance and device failure. The existing single metal diffusion barrier layer is difficult to simultaneously meet 1) the thermal expansion matching of the thermoelectric material, 2) the work function matching of the thermoelectric material and low interface resistance, and 3) the diffusion resistance and chemical stability at medium temperature and even high temperature. According to the principle, barrier layers such as FeTe, feSb and the like are acted on PbTe devices at present, but the interfaces still have a certain element diffusion problem after long-time annealing. By incorporating multiple elements in the same lattice, the multi-element alloy can adjust the coefficient of thermal expansion and enhance diffusion barrier capability while maintaining good electrical conductivity. The prior art introduces a multi-element alloy diffusion barrier layer such as Fe-Ni-Cr or FeCoNiCrMo into a system such as Mg 3(Sb,Bi)2, skutterudite and the like, thereby realizing better interface stability. However, aiming at a PbTe system, a thermal expansion matching rule, an interfacial phase evolution mechanism and long-term service behaviors of the multi-element alloy diffusion barrier layer are not researched systematically. Therefore, it is necessary to develop a novel diffusion barrier structure having thermal expansion matching, low interface resistance and high temperature chemical stability, so as to significantly improve service stability of the PbTe thermoelectric connection structure and life of the thermoelectric device. Disclosure of Invention The invention aims to solve the technical problems that the thermal expansion matching of a barrier layer used by the existing PbTe-based thermoelectric device is poor and the interface stability is poor, and provides a Fe-Cr-based multi-element alloy barrier layer of the PbTe-based thermoelectric material, a preparation method and application thereof. The first aspect of the invention provides a preparation method of a Fe-Cr-based multi-component alloy barrier layer of a PbTe-based thermoelectric material, which comprises the following steps: S1, weighing raw materials according to the chemical proportion of Pb-Te based alloy and the chemical proportion of Sn-Te based alloy, respectively obtaining corresponding cast ingots through a smelting process and annealing, and crushing and grinding into fine powder to obtain Pb-Te alloy powder and Sn-Te alloy powder; s2, weighing raw materials according to the chemical proportion of the Fe-Cr-based multi-element alloy, preparing an Fe-Cr-based multi-element alloy block by adopting an alloying method, obtaining an alloy ingot by adopting a smelting process, and crushing and grinding the alloy ingot into fine powder to obtain Fe-Cr-based multi-element alloy powder; S3, sequentially filling Pb-Te alloy powder, sn-Te alloy powder and Fe-Cr-based multi-element alloy powder into a graphite mold, and obtaining a compact Pb-Te/Sn-Te/Fe-Cr-based multi-element alloy composite block body through a spark plasma sintering process, thereby completing the preparation of the Fe-Cr-based multi-element alloy barrier layer. I