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CN-122012964-A - Ball milling synthesized Mg3(Bi,Sb)2Method for producing a base material

CN122012964ACN 122012964 ACN122012964 ACN 122012964ACN-122012964-A

Abstract

The invention belongs to the technical field of thermoelectric semiconductor material preparation, and provides a method for synthesizing Mg 3 (Bi,Sb) 2 -based material by ball milling, which comprises the steps of weighing high-purity Bi particles, sb particles and Mg scraps in a glove box under inert atmosphere, wherein the preparation time is long in the process of synthesizing magnesium-based material by a ball milling method, and the components are uneven due to cold welding and agglomeration of the material; and then placing Bi particles and Sb particles in a glove box, adding ball-milling balls with different diameters in a ball-milling tank, performing pre-milling in an inert atmosphere, adding Mg scraps under the protection of the inert atmosphere after pre-milling, fully mixing the ball-milled Bi powder, the ball-milled Sb powder and the ball-milled Mg scraps, and performing ball milling in the inert atmosphere to obtain the Mg 3 (Bi,Sb) 2 -based material. By changing the feeding sequence, the optimization of the feeding particle size is realized, so that the specific surface area of the powder is increased, the reaction speed with Mg element is improved, the phenomena of bonding of materials and tank walls and cold welding agglomeration are prevented, and the material synthesis efficiency and the component uniformity are improved.

Inventors

  • TANG ZEFENG
  • WU YONGQING
  • LIU FENG
  • LI MING
  • CUI BORAN

Assignees

  • 杭州先导热电科技有限公司

Dates

Publication Date
20260512
Application Date
20251015

Claims (10)

  1. 1. The method for synthesizing the Mg 3 (Bi,Sb) 2 -based material by ball milling is characterized by comprising the following steps of: (1) Weighing high-purity Bi particles, sb particles and Mg scraps in a glove box under an inert atmosphere; (2) In a glove box, firstly placing Bi particles and Sb particles in a ball milling tank, adding ball milling balls with different diameters, and then performing pre-ball milling in an inert atmosphere; (3) After pre-ball milling, adding Mg scraps under the protection of inert atmosphere, fully mixing the ball-milled Bi, sb powder and the Mg scraps, and then ball milling under the inert atmosphere to obtain the Mg 3 (Bi,Sb) 2 -based material.
  2. 2. The method of ball milling to synthesize Mg 3 (Bi,Sb) 2 based material according to claim 1, wherein the Mg 3 (Bi,Sb) 2 based material is a Mg-based thermoelectric material of Mg 3+δ Bi x Sb 2-x–z M y N z in composition.
  3. 3. The method for synthesizing Mg 3 (Bi,Sb) 2 -based material by ball milling according to claim 2, wherein the value of x in the magnesium-based thermoelectric material component ranges from 0 to 1.6, the value of delta ranges from 0 to 0.2, M comprises Cu, Y, sc and La admixture, the value of Y ranges from 0 to 0.03, and N comprises Te, se, S and Z ranges from 0 to 0.01.
  4. 4. The method for synthesizing Mg 3 (Bi,Sb) 2 -based material by ball milling according to claim 1, 2 or 3, wherein the purity of Bi, sb and Mg chip raw materials is more than or equal to 99.99%, and the purity of the dopant element is more than 4N.
  5. 5. The method for synthesizing Mg 3 (Bi,Sb) 2 -based materials by ball milling according to claim 1, wherein the ball milling parameters in the step 2 are that the ball-material ratio is 2-3:1, the rotating speed is 600-1000rpm/min, and the ball milling time is 1-2h.
  6. 6. The method for synthesizing Mg 3 (Bi,Sb) 2 -based material by ball milling according to claim 1 or 5, wherein the ball milling diameter is less than or equal to 5mm and is more than 0.3mm.
  7. 7. The method for synthesizing Mg 3 (Bi,Sb) 2 -based material by ball milling according to claim 6, wherein the ball milling material is selected from stainless steel balls and zirconia.
  8. 8. The method for synthesizing Mg 3 (Bi,Sb) 2 -based materials by ball milling according to claim 1, wherein the ball milling rotation speed in the step 3 is 600-1000rpm/min, and the milling time is 5-10h.
  9. 9. The method for ball-milling Mg 3 (Bi,Sb) 2 -based material according to claim 1, wherein the inert gas is argon.
  10. 10. The method for synthesizing the Mg 3 (Bi,Sb) 2 -based material by ball milling according to claim 1, which is characterized in that the conditions for sintering the Mg 3 (Bi,Sb) 2 -based material obtained by ball milling into blocks are that the pressure of vacuum hot-pressing sintering is 30-80 MPa, the sintering temperature is 600-800 ℃, and the hot-pressing sintering time is 2-10min.

Description

Method for synthesizing Mg 3(Bi,Sb)2 -based material by ball milling Technical Field The invention belongs to the technical field of thermoelectric semiconductor material preparation, and particularly relates to a preparation method for synthesizing Mg 3(Bi,Sb)2 -based materials by ball milling. Background Thermoelectric technologies around room temperature are currently monopolized by bismuth telluride based (Bi 2Te3 based) materials, however, due to the toxicity and scarcity of tellurium (Te), development of the next generation Te-free technology is critical to sustainable development. In recent years, the Mg 3(Bi,Sb)2 intermetallic compound (i.e., zintl phase) has attracted extensive attention due to non-toxicity and high element abundance, and increasing Bi concentration can shift the peak zT to lower temperatures, thereby facilitating near room temperature applications. However, the simple substance magnesium is very active in chemical property, so that the preparation of the material is complex. The common preparation methods at present are a mechanical alloy method and a smelting method. The mechanical alloy method is also a ball milling method, namely, the high-energy ball milling is carried out under inert atmosphere, firstly, materials are weighed according to the chemical element proportion, meanwhile, the high-energy ball milling is carried out after feeding, the ball milling time of the material synthesis of 10g reaches 10H or even higher, in the high-energy ball milling process, the material is also required to be controlled, the bonding between the material and a ball milling tank body or the agglomeration caused by cold welding is prevented, the problem of component uniformity is solved, in addition, the agglomeration problem cannot be avoided after the ball milling time is prolonged, and the performance of the subsequent material is also influenced to a certain extent. The smelting method is limited by the activity of magnesium simple substance and is easy to react with a quartz tube, so that the common process is to use metal tantalum as a container, seal the material in the tantalum tube and seal the material in the quartz tube for high-temperature smelting. Disclosure of Invention In order to solve the problems of long preparation time, uneven components and the like caused by cold welding agglomeration of materials in the process of synthesizing magnesium-based materials by a ball milling method, the invention provides a method for synthesizing Mg 3(Bi,Sb)2 -based materials by high-efficiency ball milling. The technical scheme of the invention is as follows, the method for synthesizing the Mg 3(Bi,Sb)2 -based material by ball milling comprises the following steps: (1) Weighing high-purity Bi particles, sb particles and Mg scraps in a glove box under an inert atmosphere; The Mg 3(Bi,Sb)2 -based material comprises an N-type Mg 3+δBixSb2-x–zMyNz magnesium-based thermoelectric material. Wherein, the value range of x is 0-1.6, the value range of delta is 0-0.2, M comprises Cu, Y, sc, la doping agent, the value range of y is 0-0.03, N comprises Te, se, S and Z is 0-0.01. Preferably, the purity of the Bi, sb and Mg chip raw materials is 99.99% or more, the purity of the dopant element is 4N or more, and the equivalent reagent (4N) represents that the content of the main component is 99.99% or more. (2) In a glove box, firstly placing Bi particles and Sb particles in a ball milling tank, adding ball milling balls with different diameters, and then performing pre-ball milling in an inert atmosphere to refine powder particles; The ball milling parameters are that the ball-material ratio is 2-3:1, the rotating speed is 600-1000rpm/min, and the ball milling time is 1-2h. Preferably, the ball diameter is less than or equal to 5mm, and more preferably >0.3mm, the ball diameters are 5mm,3mm and 1mm respectively, and the ball number ratio is 1-2:2-3:2-3 respectively. Preferably, the ball mill ball material is selected from stainless steel balls and zirconia. (3) After pre-ball milling, adding Mg scraps under the protection of atmosphere, fully mixing the ball-milled Bi, sb powder and the Mg scraps, and then ball milling under inert atmosphere to obtain the Mg 3(Bi,Sb)2 -based material. Preferably, the rotation speed is 600-1000rpm/min, and the grinding time is 5-10h. The Mg 3(Bi,Sb)2 -based material is doped in a small amount, so that there is no requirement for addition, and preferably, the doping amount is added in step 3. The inert atmosphere is preferably argon, nitrogen is avoided, and the nitrogen and magnesium are prevented from reacting. After the Mg 3(Bi,Sb)2 base material obtained by ball milling synthesis is sintered into blocks, the thermoelectric performance uniformity is obviously improved, and the thermoelectric figure of merit zT is improved. Preferably, the pressure of vacuum hot-pressing sintering is 30-80 MPa, the sintering temperature is 600-800 ℃, and the hot-pressing sintering tim