CN1422969A - Co-Sb series skutterudite compound thermoelectric material preparation method - Google Patents

Abstract

There is a manufacturing method of Co-Sb serial cobalt compound thermoelectricity materials, the steps is: 1) mechanism alloy process: the materials atomic proportion is Co:Sb=1:3, then the material powder is blended with grinding ball to carry on high energy ball grinding process, the weight proportion of ball material is 10:1-20:1, the rotate speed is 180-350 revolution/minute, the time is 8-11 hours under protective gas. 2) equal temperature quenching process: the material is equal temperature quenching processed under the protection vacuum or inert gases, the temperature is: 923-1023K, the time is :1-3 hours. The invention uses two segment processing method, then the material is quenching processed and gets the CoSb3 compound with a short time.

Description

Co-Sb is the preparation method of skutterudite compound thermoelectric material

Technical field

The invention belongs to materials processing and preparing technical field, be specifically related to the preparation method that a kind of Co-Sb is a skutterudite compound thermoelectric material.

Background technology

At present, filled skutterudite compound (Filled Skutterudite) is a kind of type material with good thermoelectricity capability that is subjected to extensive concern.It is gained the name because of the Skutterud small town that originates in Norway.The chemical formula of skutterudite compound can be written as XY ₃, contain 8 XY in each unit cell ₃Molecule.Wherein the X atom can be Co, Ir, and Fe, metallic elements such as Rh, the Y atom can be P, As, VA family elements such as Sb.Wherein again with CoSb ₃Hole maximum in the lattice by to filling rare earth or other atoms metal of big quality in the lattice hole, is filled the vibration effect of atom in hole, can reduce the lattice thermal conductivity of material greatly, thereby the thermoelectricity capability of material is greatly enhanced.Co-Sb is that phasor shows, Co, Sb two component fusing points differ greatly, for CoSb ₃With filling CoSb ₃Material, there is certain difficulty in existing smelting preparation method, in addition CoSb ₃Compound is a Peritectic Reaction product, is difficult to directly obtain this compound by smelting process, also needs long soak to handle (all needing more than two days usually) after the melting and can obtain required tin white cobalt and filled skutterudite compound-material.Therefore short solid state reaction preparation method consuming time has been subjected to attention, with the powder of composition material by after certain proportioning components, insulation for a long time in the scope of 873～1073K, generate skutterudite compound thermoelectric material by the solid state reaction between component and (see the 1. Jue Wei of Songyuan City, A Wu is grand bright, and Xiao Liu is firm.ま て り あ, 1996,35 (9): 948-951; 2. crack Li Dong, powder お I び powder metallurgy, 1999,46 (9): 921-926; 3. L.Chapon, D.Ravot, J.C.Tedenac.Journal of Alloysand Compounds, 1999,282:58-63; 4. Tang Xin peak etc.Chinese science B collects: chemistry, 2000,43 (3): 306-312): the subject matter of the current existence of this solid state reaction preparation method is: 1) material preparation overlong time, existing solid state reaction soaking time are at least all more than 18 hours.2) be difficult to obtain single-phase tin white cobalt and filled skutterudite compound-material, often also have Sb, CoSb in the reaction product ₂Compound or other impurity.Must just can obtain monophasic tin white cobalt and filled skutterudite compound thermoelectric material through further purification processes.Therefore the preparation time of material is long, and energy consumption is big, the cost height.

Summary of the invention

The object of the present invention is to provide a kind of Co-Sb that overcomes above-mentioned defective is the preparation method of skutterudite compound thermoelectric material, and this method can reduce energy consumption, shorten CoSb ₃Compound time to 13 hour with interior, obtain single-phase CoSb simultaneously ₃The preparation method of compound.

For achieving the above object, a kind of Co-Sb is the preparation method of skutterudite compound thermoelectric material, may further comprise the steps:

(1) pre-mechanical alloying is handled: with raw material powder according to atomic ratio Co: Sb=1: 3 proportionings, again raw material powder and abrading-ball being carried out high-energy ball milling after mixed handles, ball material weight ratio is 10: 1～20: 1, rotational speed of ball-mill is 180-350 rev/min, and (energy input 12.3～15.5MJ) carried out under protective atmosphere ball-milling processing 8-11 hour;

(2) isothermal annealing is handled: will carry out isothermal annealing under the protection of vacuum or inert atmosphere through the material after the pre-alloyed processing again and handle, treatment temp is 923～1023K, and the treatment time is 1～3 hour.

The essential distinction of patent of the present invention and existing solid reaction process is: existing solid reaction process does not have mechanical alloying to handle this technological process, and it at high temperature is incubated processing for a long time; The process that the present invention also handles through pre-mechanical alloying before insulation is handled, the material after mechanical alloying is handled are handled to react at short notice through insulation again and are generated the required compound material.Because patent of the present invention adopts pre-alloyed two sections working methods handling in conjunction with solid phase, the material after mechanical alloying is handled through the short period of time anneal get final product single-phase CoSb ₃Skutterudite compound.Comprise that the whole material preparation process time that mechanical alloying is handled shortens 6 hours at least, because the high temperature isothermal annealing time shortened more than 10 hours, and whole material preparation process energy consumption significantly reduces, the preparation cost of material can reduce significantly simultaneously.

Description of drawings

Fig. 1 is CoSb ₃With filling CoSb ₃The compound schema;

Fig. 2 handles the X-ray diffractogram of back material for mechanical alloying and isothermal annealing.

Embodiment

The inventive method comprises pre-alloyed and two material processings of isothermal annealing.At first handle by original composition material being carried out mechanical alloying, make each component reach evenly mixed, generating portion tin white cobalt and filled skutterudite compound, the tissue of the material of refinement simultaneously, shorten diffusion length between the xenogenesis atom, improve the Gibbs free energy of mixed system; To carry out after isothermal annealing is handled solid state reaction taking place again through the material after the pre-alloyed processing of machinery and generate single-phase skutterudite compound.

For CoSb ₃Compound, starting material are Co, Sb simple substance powder, and according to atomic ratio Co: Sb=1: 3 carry out stoicheiometry, the mixed powder for preparing is carried out pre-mechanical alloying earlier handle, it is a high-energy ball milling process that mechanical alloying is handled, and this process is carried out on planetary high-energy ball mill.Mixing with certain ratio of grinding media to material (10: 1), is that 180-350 rev/min rotating speed high-energy ball milling was handled 8-12 hour with the rotating speed, and whole ball-milling processing process powdered material all is under the protection of high-purity argon gas.Preprocessing process also can carry out on other high energy ball mill.After pre-alloyed processing, the weave construction of material obtains refinement, has shortened diffusion length between the xenogenesis atom, has improved the Gibbs free energy of mixed system.There is the part skutterudite compound to generate.

The isothermal annealing process adopts general heat treatment furnace, and thermal treatment temp is 923～1023K, and soaking time is 1-3 hour.Pre-alloying powder can also can be handled after coldmoulding more directly with the powdered form isothermal processes.The entire treatment process places pre-alloying powder or pressed compact under the protection of vacuum or inert atmosphere with anti-oxidation.In the isothermal processes process solid state reaction taking place, can obtain single-phase CoSb ₃Compound or filling CoSb ₃Compound-material.As seen Fig. 2 adopts the inventive method can obtain monophasic CoSb for adopting the X-ray diffractogram of the prepared final material of aforesaid method ₃Compound.

Can implement according to each listed among following embodiment processing parameter.

The embodiment sequence number	Material	The pre-treatment ratio of grinding media to material	The pre-treatment rotating speed	Pretreatment time	Pre-treatment total input energy (* 10 6J)	Isothermal treatment temperatures	The isothermal processes time	Obtain single-phase skutterudite compound overall treatment time
									????1	??CoSb 3	????10	?350rpm	????8h	????13.0	??1023K	????1h	????9h
????2	??CoSb 3	????15	?350rpm	????8h	????13.0	??1000K	????1h	????9h
									????3	??CoSb 3	????20	?350rpm	????8h	????13.0	??923K	????1h	????11h
????4	??CoSb 3	????10	?250rpm	????10h	????15.5	??1023K	????1h	????11h
									????5	??CoSb 3	????15	?250rpm	????10h	????15.5	??973K	????1h	????11h
????6	??CoSb 3	????20	?250rpm	????10h	????15.5	??923K	????1h	????11h

????7	??CoSb 3	????10	?180rpm	??11h	??12.3	??1023K	????1h	????12h
									????8	??CoSb 3	????15	?180rpm	??11h	??12.3	??973K	????1h	????12h
????9	??CoSb 3	????20	?180rpm	??11h	??12.3	??923K	????1h	????12h

Claims (2)

1, a kind of Co-Sb is the preparation method of skutterudite compound thermoelectric material, may further comprise the steps:

(1) pre-mechanical alloying is handled: with raw material powder according to atomic ratio Co: Sb=1: 3 proportionings, again raw material powder and abrading-ball being carried out high-energy ball milling after mixed handles, ball material weight ratio is 10: 1～20: 1, rotational speed of ball-mill is 180-350 rev/min, and (energy input 12.3～15.5MJ) carried out under protective atmosphere ball-milling processing 8-11 hour;

(2) isothermal annealing is handled: will carry out isothermal annealing under the protection of vacuum or inert atmosphere through the material after the pre-alloyed processing again and handle, treatment temp is 923～1023K, and the treatment time is 1～3 hour.

2, according to the preparation method of claim 1, it is characterized in that: the ball-milling processing time is 8-11 hour in the described pre-alloyed treating processes.

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