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CN-121976141-A - Bismuth telluride-based thermoelectric material high-binding-force barrier layer and preparation method and application thereof

CN121976141ACN 121976141 ACN121976141 ACN 121976141ACN-121976141-A

Abstract

The invention discloses a high-binding force blocking layer of bismuth telluride-based thermoelectric material, a preparation method and application thereof, wherein the preparation method comprises the following steps of S1, providing p-type and n-type bismuth telluride-based thermoelectric material blocks subjected to cutting and surface pretreatment; S2, taking Fe-based alloy powder as a raw material, depositing on the high-temperature end surface of the p-type and n-type bismuth telluride-based thermoelectric material blocks in a thermal spraying mode to form an Fe-based alloy barrier layer, and performing heat treatment on the Fe-based alloy barrier layer to finish the preparation of the bismuth telluride-based thermoelectric material high-binding force barrier layer. The barrier layer breaks through the bottleneck that the existing Ni or other metal barrier layers are easy to fail in the high-temperature service process, and the reliability and the service life of the bismuth telluride-based thermoelectric device are obviously improved.

Inventors

  • JIANG JUN
  • ZHOU CHUANDONG
  • 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
20251209

Claims (9)

  1. 1. The preparation method of the high-binding-force blocking layer of the bismuth telluride-based thermoelectric material is characterized by comprising the following steps of S1, providing a p-type and n-type bismuth telluride-based thermoelectric material block body subjected to cutting and surface pretreatment; s2, taking Fe-based alloy powder as a raw material, and depositing on the high-temperature end surfaces of the p-type and n-type bismuth telluride-based thermoelectric material blocks in a thermal spraying mode to form an Fe-based alloy barrier layer; S3, performing heat treatment on the Fe-based alloy barrier layer to finish preparation of the high-binding-force barrier layer of the bismuth telluride-based thermoelectric material; The Fe-based alloy powder is at least one selected from the group consisting of Fe 83 Mn 17 alloy, fe 64 Ni 36 alloy, fe 82 Cr 18 alloy, fe 71 Ni 20 Cr 9 alloy and Fe 40 Ni 20 Cr 20 Co 20 alloy.
  2. 2. The method according to claim 1, wherein the particle size of the Fe-based alloy powder is 15 to 53 μm.
  3. 3. The preparation method according to claim 1, wherein the cutting and surface pretreatment in step S1 is to cut and polish the p-type and n-type bismuth telluride-based thermoelectric material block according to the size, and the high temperature end surface is roughened by grinding with 800-2000 mesh sand paper or sand blast, and then ultrasonic cleaning with alcohol.
  4. 4. The preparation method according to claim 1, wherein the thermal spraying mode in the step S2 is plasma spraying, flame spraying or electric arc spraying, the distance between a spray gun and a substrate is 150-300mm, the powder feeding rate is 15-30g/min, the scanning speed of the spray gun is 400-600mm/S, and the spraying power is 20-30kW.
  5. 5. The preparation method according to claim 1, wherein the heat treatment in step S3 is performed under an inert atmosphere, the temperature is raised to 250-450 ℃, the holding time is 0.5-3h, and the furnace is cooled or cooled in a controlled cooling manner.
  6. 6. The method according to claim 7, wherein the temperature rise rate in step S3 is 3 to 10 ℃.
  7. 7. A high binding force barrier layer of bismuth telluride based thermoelectric material, characterized in that it is prepared by the preparation method of any one of claims 1-6.
  8. 8. The bismuth telluride-based thermoelectric material high binding force blocking layer according to claim 7, wherein the blocking layer is a layered-microporous composite structure with the thickness of 20-100 μm, the layers are formed by melt-flap layers stacked layer by layer along the spraying direction, and the volume fraction of micropores is 1-20%.
  9. 9. Use of a high adhesion barrier layer of a bismuth telluride-based thermoelectric material according to claim 7 or 8 in a thermoelectric device.

Description

Bismuth telluride-based thermoelectric material high-binding-force barrier layer and preparation method and application thereof Technical Field The invention relates to the technical field of thermoelectric devices, in particular to a bismuth telluride-based thermoelectric material high-binding-force barrier layer, a preparation method and application thereof. Background Bismuth telluride and its solid solutions have been widely used in the thermoelectric refrigeration and low-grade cogeneration fields for a long time because of their excellent thermoelectric properties at near room temperature. Typical bismuth telluride-based thermoelectric devices are generally composed of p-type and n-type thermoelectric materials, diffusion barriers, solder layers, metal electrodes, and ceramic substrates, with the high temperature end being subjected to a large temperature gradient for a long period of time, which is the primary area where the device ages and fails. The interface diffusion behavior is one of the key factors limiting the service life of bismuth telluride devices, and during the operation of the device, the solder and the metal electrode can react with the bismuth telluride matrix or migrate, so that the high-temperature end interface gradually forms a brittle intermetallic phase. The formation of these phases not only disrupts the interfacial continuity, causing a rapid increase in contact resistance, but also induces microcrack propagation under thermal cycling conditions, ultimately leading to device failure. Therefore, constructing a barrier layer having high stability and high bonding force on the surface of the thermoelectric material is a necessary measure to ensure long-term reliability of the device. In the prior bismuth telluride device barrier layer material, metal Ni is widely used in commercial refrigeration modules due to higher conductivity, mature process and relatively close thermal expansion coefficient to bismuth telluride. However, ni at 473K or more undergoes a continuous chemical reaction with Bi and Te, and intermetallic compounds such as Ni-Bi and Ni-Te are gradually formed at the interface. The formation of these brittle compounds results in a significant increase in interfacial resistance and severe thermal stress concentrations at the hot end. Along with the extension of the service time, cracks at the interface further expand, so that the Ni barrier layer is difficult to meet the requirement of stability of the thermoelectric power generation module in long-term operation at a higher temperature. In recent years, some transition metals such as Ti, fe, etc. have also been tried as barrier layers. However, these materials may still undergo oxidation, diffusion or reaction at higher temperatures, and the interfacial bonding force formed by these materials is limited, and it is difficult to satisfy the requirements of low contact resistance, thermal expansion matching, long-term stability, and the like. In addition, although different metals can be deposited in a film electroplating or sputtering mode, the formed thin layer has low bonding force, is easy to peel off under the thermal cycle condition, and is difficult to realize a barrier layer structure which has uniform and compact thickness and adjustable mechanical property on a thermoelectric arm with complex geometry. Therefore, the prior barrier layer material still has difficulty in meeting the requirement of the high Wen Oudi bismuth thermoelectric device on long-term service performance in terms of thermal stability, mechanical buffering capacity and interface integrity. In summary, there is a need to develop a barrier layer material that has high thermal stability, excellent diffusion inhibition capability, good thermal expansion matching, and can maintain interfacial integrity under long-term temperature differential loading, so as to break through the bottleneck that the existing Ni or other metal barrier layer is susceptible to failure during high-temperature service, thereby significantly improving the reliability and service life of bismuth telluride-based thermoelectric devices. Disclosure of Invention The invention aims to solve the technical problems that the barrier layer of the traditional bismuth telluride-based thermoelectric device has weak bonding force and poor high-temperature stability, and provides a high-bonding force barrier layer of a bismuth telluride-based thermoelectric material, a preparation method and application thereof. The technical scheme of the first aspect of the invention is that the preparation method of the high-binding-force blocking layer of the bismuth telluride-based thermoelectric material comprises the following steps: s1, providing a p-type and n-type bismuth telluride-based thermoelectric material block subjected to cutting and surface pretreatment; s2, taking Fe-based alloy powder as a raw material, and depositing on the high-temperature end surfaces of the p-type and n-type b