阅读说明：本技术 一种优化碲化铅基热电材料/电极接头性能的方法 (Method for optimizing lead telluride-based thermoelectric material/electrode joint performance ) 是由 陈少平 王雅宁 樊文浩 王文先 吴玉程 孟庆森 于 2019-09-27 设计创作，主要内容包括：本发明是一种优化碲化铅基热电材料/电极接头性能的方法,属于热电器件制备和连接件技术领域,该方法在界面处构建缺陷的化学势平衡,通过形成中间层,降低与热电材料的接触势垒,实现降低其界面接触电阻的目的,并通过扩散作用提高热电材料与电极材料界面处剪切强度。本发明的优点及用途在于：控制与电极材料FexPb<Sub>0.15</Sub>Te<Sub>1-x-0.15</Sub>(0.6≤x≤0.8)中的Te含量调控点缺陷浓度,在外加电场和压力场的耦合作用下,在实现热电材料和电极材料致密化的同时,同步实现二者之间的扩散反应形成连接。(The invention relates to a method for optimizing the performance of a lead telluride-based thermoelectric material/electrode joint, which belongs to the technical field of thermoelectric device preparation and connecting pieces. The invention has the advantages and the purposes that: FexPb as control and electrode material 0.15 Te 1‑x‑0.15 The Te content in (x is more than or equal to 0.6 and less than or equal to 0.8) regulates the defect concentration of the point, and under the coupling action of an external electric field and a pressure field, the densification of the thermoelectric material and the electrode material is realized, and simultaneously, the diffusion reaction between the thermoelectric material and the electrode material is realized to form connection.)

1. A method for optimizing the performance of lead telluride-based thermoelectric material/electrode joint is characterized by controlling the Fe content in electrode material_XPb_0.15Te_1-x-0.15The content of Te in (x is more than or equal to 0.6 and less than or equal to 0.8) realizes the densification of the electrode material and the thermoelectric material under the coupling action of an electric field and a pressure field, and simultaneously realizes the connection of the electrode material and the thermoelectric material by synchronously utilizing the diffusion action, and the specific steps are as follows:

(1) mixing raw materials: weighing Pb and Te with particle size less than 100nm and purity greater than 99.9% according to non-stoichiometric ratio, and mixing to obtain Pb_50.01Te_49.99Mixing the powder, smelting at 1000 deg.C for 6 hr, quenching, annealing at 700 deg.C for 48 hr, grinding into powder 1, and mixing Fe, Pb and Te with granularity less than 100nm and purity greater than 99.9% at a certain proportion to obtain Fe_XPb_0.15Te_1-x-0.15(x is more than or equal to 0.6 and less than or equal to 0.8) mixed powder 2;

(2) filling the powder into a die: putting the powder 2 into a graphite die, cold-pressing to 50-60% of theoretical density, then placing the powder 1 above the powder 2, and cold-pressing again to 50-60% of theoretical density for later use;

(3) sintering and connecting: grinding the annealed thermoelectric material sample, sequentially paving the ground thermoelectric material sample and the electrode material in a graphite mold, changing the content of the Te of the electrode material, and performing SPS sintering at the sintering temperature of 400-600 ℃, the pressure of 40-45 MPa and the heat preservation time of 15-20 min to form Fe_XPb_0.15Te_1-x-0.15(0.6≤x≤0.8)/Pb_50.01Te_49.99/Fe_XPb_0.15Te_1-x-0.15(x is more than or equal to 0.6 and less than or equal to 0.8), and annealing the joint at the temperature of 450-500 ℃ for 30-35 min.

2. The method for optimizing the performance of the lead telluride-based thermoelectric material/electrode joint as in claim 1, wherein the method comprises the following steps: the electrode material is Fe_xPb_0.15Te_1-x-0.15(0.6≤x≤0.8)。

Technical Field

The invention discloses a method for optimizing the performance of a lead telluride-based thermoelectric material/electrode joint, and belongs to the technical field of thermoelectric device preparation and connecting pieces. Pb and Te are doped into the electrode material, and the intermediate layer is obtained at the interface by utilizing the diffusion of elements, so that the potential barrier between the electrode material and the thermoelectric material is reduced, the aim of reducing the contact resistance is fulfilled, and meanwhile, the shear strength of the material is improved by utilizing the diffusion of the elements.

Background

The lead telluride-based thermoelectric material is an ideal and mature medium-temperature thermoelectric material. As a defect compound, excess or absence of Pb atoms in a lead telluride-based thermoelectric material affects the formation of intrinsic defects thereof, and thus semiconductor properties thereof. In the process of connecting the lead telluride-based thermoelectric material and the electrode, atoms are promoted to be directionally transported along the direction vertical to the interface by the combined action of temperature and chemical potential gradient, so that the balance of intrinsic defects in the thermoelectric material matrix is destroyed, the interface contact resistance is increased, and the thermoelectric conversion performance of the joint is degraded. And because the connection mode is mechanical occlusion, the joint shear strength is lower.

Disclosure of Invention

The invention relates to a method for optimizing the performance of a lead telluride-based thermoelectric material/electrode joint, which aims to realize that a middle layer is a mixture of PbTe and Fe through the diffusion of Pb and Te in an electrode material, the mixture still shows metallicity and belongs to a part of the electrode material, but compared with the original electrode material, the potential barrier between the electrode material and the thermoelectric material is reduced, so that the aims of reducing contact resistance and improving shear strength are fulfilled at the same time.

The invention relates to a method for optimizing the performance of a lead telluride-based thermoelectric material/electrode joint, which controls the Fe of an electrode material_XPb_0.15Te_1-x-0.15The content of Te in (x is more than or equal to 0.6 and less than or equal to 0.8) realizes the densification of the electrode material and the thermoelectric material under the coupling action of an electric field and a pressure field, and simultaneously realizes the synchronous diffusion reaction connection of the electrode material and the thermoelectric material by utilizing the diffusion action, and the specific steps are as follows:

(1) mixing raw materials: pb and Te with particle size less than 100nm and purity greater than 99.9% are non-stoichiometricWeighing the mixture in proportion and fully mixing the mixture to obtain Pb_xTe_1-x(x is not less than 0.4999 and not more than 0.5006) mixing the powder, carrying out smelting at 1000 ℃ for 6 hours, then quenching, carrying out annealing treatment at 700 ℃ for 48 hours, then grinding into powder 1, and mixing Fe with granularity of less than 100nm and purity of more than 99.9%, Pb and Te according to a proportion to obtain Fe_XPb_0.15Te_1-x-0.15(x is more than or equal to 0.6 and less than or equal to 0.8) mixed powder 2;

(2) filling the powder into a die: putting the powder 2 into a graphite die, cold-pressing to 50-60% of theoretical density, then placing the powder 1 above the powder 2, and cold-pressing again to 50-60% of theoretical density for later use;

(3) sintering and connecting: grinding the annealed thermoelectric material sample, sequentially spreading the ground thermoelectric material sample and the electrode material in a graphite mold, changing the content of the Te of the electrode material, and performing SPS sintering at the sintering temperature of 400-600 ℃, the pressure of 40-45 MPa and the heat preservation time of 15-20 min to form Fe_XPb_0.15Te_1-x-0.15(0.6≤x≤0.8)/Pb_50.01Te_49.99/Fe_XPb_0.15Te_1-x-0.15(x is more than or equal to 0.6 and less than or equal to 0.8), and annealing the joint at the temperature of 450-500 ℃ for 30-35 min.

Drawings

In FIG. 1, 2, 3 and 4 respectively represent that the electrode material is 1:/Fe and 2/Fe_0.8Pb_0.15Te_0.05;3:/Fe_0.7Pb_0.15Te_0.15;4:/Fe_0.6Pb_0.15Te_0.25Shear strength and contact resistance of the sample.

Detailed Description

Early experiments show that Pb is_xTe_1-x(0.4999 ≦ x ≦ 0.5006) thermoelectric material, which has the best thermoelectric material performance when x =0.5001, so in the embodiment, electrode materials Pb with different Te contents are prepared on the basis of x =0.5001 respectively_50.01Te_49.99With the electrode material Fe_xPb_0.15Te_1-x-0.15(x is more than or equal to 0.6 and less than or equal to 0.8) connection.