Process for treating orientation texture of thermoelectric ceramic material

A technology of ceramic materials and thermoelectric materials, which is applied in the field of orientation texture treatment of thermoelectric ceramic materials, can solve the problems of complex process, limited application, long process time, etc., and achieve the effect of obvious effect and improved thermoelectric performance

Inactive Publication Date: 2005-06-01
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the existing ceramic texture methods all have complex processes and long process times, which are not conducive to large-scale industrial production.
For example, the processing time of the RTGG method exceeds 30 hours, and the magnetic field orientation method needs to be processed in a magnetic field of up to 3 Tesla for 16 hours, which greatly limits their applications.

Method used

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  • Process for treating orientation texture of thermoelectric ceramic material
  • Process for treating orientation texture of thermoelectric ceramic material
  • Process for treating orientation texture of thermoelectric ceramic material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018]Weigh a certain amount of Ca(NO 3 ) 2 , Co(NO 3 ) 2 ·6H 2 O and citric acid, Ca-Co-O-based ceramic precursor powder was synthesized by sol-gel method. The XRD spectrum shows that the precursor powder has no other impurity phases. Pour a certain amount of precursor powder into a graphite mold, place the mold in an SPS furnace, apply a constant pressure of 50MPa, and sinter at 750°C for 5 minutes to obtain a density of 98.1%. Ca-Co-O-based thermoelectric materials. figure 1 The XRD analysis shown shows that the phase is a single Ca 3 co 4 o 9 The sintering performance is good, and the Logtering orientation factor calculated according to the XRD spectrum is only 0.31, indicating that SPS sintering does not lead to obvious orientation texture, and the role of SPS is mainly to obtain a high-density ceramic green body. The thermoelectric performance test shows that the conductivity of the sample is 117.74S / cm at 700°C, the Seeback coefficient is 172.63μV / K, and the pow...

Embodiment 2

[0020] After the SPS sintered ceramic body in Example 1 was calcined to remove carbon, it was placed in a hot forging furnace at 900°C, and a certain pressure load of 40 MPa was applied to cause lateral deformation, thereby obtaining a highly oriented thermoelectric ceramic with good performance. XRD analysis of the Ca-Co-O-based hot-forged samples showed that ( figure 1 As shown), the (001) peak intensity of the hot-forged sample is significantly enhanced, and the Logtering orientation factor is 0.82, indicating that the hot-forged sample has a high degree of orientation arrangement structure. At 700°C, the conductivity of the sample is 133.10S / cm, the Seeback coefficient is 183.81μV / K, and the power factor is 4.50×10 -4 w -1 K -2 . Its corresponding data such as figure 1 , figure 2 , image 3 , Figure 4 (b) shown.

Embodiment 3

[0022] Weigh a certain amount of Ca(NO 3 ) 2 , La(NO 3 ) 3 ·6H 2 O, Co(NO 3 ) 2 ·6H 2 O and citric acid, La-Ca-Co-O-based ceramic precursor powder was synthesized by sol-gel method. The XRD spectrum shows that the precursor powder has no other impurity phases. Pour a certain amount of precursor powder into a graphite mold, place the mold in an SPS furnace, apply a constant pressure, and sinter at 750°C for 5 minutes to obtain a density of 98.4%. La-Ca-Co-O-based thermoelectric materials. XRD shows that the phase is single (Ca 0.9 La 0.1 ) 3 co 4 o 9 Solid solution phase, good sintering performance, according to XRD spectrum ( Figure 5 Shown) the calculated Logtering orientation factor is only 0.40, SEM ( Figure 6 ) also shows that there is no obvious orientation arrangement of the grains, indicating that SPS sintering alone cannot introduce a highly oriented texture, but compared with Ca-Co-O-based thermoelectric materials, the incorporation of La is more condu...

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Abstract

The present invention is orientation texture treating process of thermoelectric ceramic material in material treating technology. Ca-Co-O system and La-Ca-Co-O system are taken as the experiment objects, and through sol-gel process to synthesize precursor powder, sintering in spark plasma sintering furnace to form ceramic, and hot forging to orientate at high temperature to make ceramic material possess better plasticity and ductility, thermoelectric oxide material with density as high as 98-99 % and high orientated texture may be obtained. The said treating process makes the Ca-Co-O system possess 13 % raised conductivity and 28 % raised power factor at 700 deg.c and the La-Ca-Co-O system possess 29.3 % raised conductivity and 61.3 % raised power factor at 700 deg.c. The said treating process is simple and short in treating time and can improve the processing of thermoelectric ceramic obviously.

Description

technical field [0001] The invention belongs to the technical field of material processing, and in particular relates to an orientation texture processing technology of a thermoelectric ceramic material which has a simple process method and short processing time and can significantly improve the performance of the thermoelectric ceramic. Background technique [0002] In recent years, due to the need of environmental protection, the research of new thermoelectric materials has attracted more and more attention. Thermoelectric materials are carriers for reversible conversion of heat energy and electric energy. Thermoelectric devices with thermoelectric materials as the core module have the advantages of light structure, small size, long service life, no pollution to the environment, and can be used under very harsh environmental conditions. And other advantages, and the reversibility of the thermoelectric effect also determines that the thermoelectric device has bidirectionali...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/01C04B35/622C04B35/624C04B35/64
Inventor 刘宇恒南策文沈志坚林元华施展
Owner TSINGHUA UNIV
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