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Production method for sintered metal-ceramic layered compact and production method for thermal stress relief pad

a technology of sintered metal and compact, which is applied in the manufacture/treatment of thermoelectric devices, metal-working apparatuses, thermoelectric device details, etc., can solve the problems of thermal stress relief pad short circuit, time-consuming, and numerous processes, and achieve efficient performance and reduce the number of processes

Inactive Publication Date: 2005-01-06
HITACHI POWDERED METALS COMPANY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

"The present invention provides a production method for a sintered metal-ceramic layered compact and a thermal stress relief pad for thermoelectric conversion elements. The method involves filling and layering metal and ceramic powders, or a mixture of the two, and compacting the layered powders to form a green compact. The green compact is then sintered at a lower temperature in a non-oxidizing atmosphere to achieve efficient production. The method reduces the number of processes and ensures reliable performance of the metal-ceramic layered compact. The ceramic powder can include low melting point powders, such as boric acid or anhydrous borax, mixed with a binder like methyl cellulose or polyvinyl alcohol. The mixed powder can also include a combination of low melting point powders with different compositions. The method can be performed using a microwave heating furnace with a cooling device. The invention also provides a production method for a thermal stress relief pad for thermoelectric conversion elements, which involves filling and layering an electrical insulating powder and a metal powder in a cavity of a die, and forming a green compact by compacting the layered powders. The method reduces the number of processes and ensures reliable performance of the thermal stress relief pad."

Problems solved by technology

Due to this, the above techniques require numerous processes, are time consuming, and are troublesome.
In this case, metal foil is formed on the outer face of the electrical insulating layer, and causes a short circuit in the thermal stress relief pad.
However, since this green compact is sintered at a temperature at which copper does not melt, an alumina compact of the electrical insulating layer is not sintered well, and cracks thereby occur at the electrical insulating layer portion.

Method used

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  • Production method for sintered metal-ceramic layered compact and production method for thermal stress relief pad
  • Production method for sintered metal-ceramic layered compact and production method for thermal stress relief pad
  • Production method for sintered metal-ceramic layered compact and production method for thermal stress relief pad

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Experimental program
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Effect test

first embodiment

[0041] (A) First Embodiment

[0042] Desirable materials and production method in which the desirable materials are used according to the first embodiment will be described in detail hereinafter.

[0043] (1) Ceramic Powder

[0044] A Ceramic powder is composed of alumina or aluminum nitride, which has good electrical insulation and good thermal conductivity. In this case, in particular, alumina has better powder compression compactibility than that of aluminum nitride, and has a lower melting point than that of aluminum nitride, thereby being favorably used. A ceramic powder as a component of a ceramic layer is favorably densified as high as possible by compacting, and has good sinterability, thereby favorably having fine grain size. When a ceramic powder has low flowability due to fine grain size thereof, the ceramic powder is favorably granulated by using a binder such as carboxymethyl cellulose (CMC) so as to have a particle diameter of about 50 to 150 μm, and the flowability thereof i...

second embodiment

[0089] (B) Second Embodiment

[0090] Desirable materials and production method in which the desirable materials are used according to the second embodiment will be described hereinafter. In the second embodiment, description of the same materials and structures as that of the first embodiment are omitted.

[0091] (1) Ceramic Powder

[0092] The same ceramic powder as that of the first embodiment is used.

[0093] (2) Low Melting Powder Added to Ceramic Powder

[0094] A ceramic powder composed of only ceramic powder is hardly sintered when heated to a temperature in which the metal layer is sintered. Due to this, the ceramic layer may possibly collapse when a strong impact is imparted thereto although the ceramic layer may be handled. Therefore, the same low melting point powder as that of the first embodiment is used so as to improve the strength of the ceramic layer.

[0095] (3) Binder for Ceramic Powder

[0096] The same binder for the ceramic powder as that of the first embodiment is used. ...

third embodiment

[0114] (C) Third Embodiment

[0115] Desirable materials and production method in which the desirable materials are used according to the third embodiment will be described hereinafter.

[0116] (1) Metal Powder

[0117] A metal layer having electrical conductivity and thermal conductivity is made of a metal powder. The metal powder is composed of one of copper, aluminum, silver, and nickel, or mixture of at least two of copper, aluminum, silver, and nickel. For example, the mixture is composed of copper and aluminum. These powders have good compressibility, and these powders favorably have predetermined grain sizes so as to pass through a 100-mesh sieve, thereby being easily filled into a die. When a fine powder is used, flowability can be improved by granulating. These metal powders used in a mixed powder with an electrical insulation powder are selected so that the mixed powder has low segregation degree and good flowability in consideration of grain size distribution of the electrical ...

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Abstract

The present invention provides a production method for a sintered metal-ceramic layered compact, comprising steps of: filling and layering a metal powder and a ceramic powder, or filling and layering a metal powder, a mixed powder of a metal powder and a ceramic powder, and a ceramic powder; forming a green compact of the layered powders by compacting the layered powders; and sintering a layer including the metal of the green compact at a temperature of lower than a melting point of the metal by heating by irradiation of microwaves in a non-oxidizing atmosphere.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a production method for producing metal-ceramic layered compacts by using a powder metallurgy technique, and relates to a production method for producing thermal stress relief pads for thermoelectric conversion elements by using a powder metallurgy technique. The metal-ceramic layered compact is heat resistant and thermally conductive, or is electrically insulated at one portion thereof and electrically conductive and thermally conductive at another portion thereof, and has a required thermal stress relief function. The thermal stress relief pad has a structure in which metal and ceramic are layered and which is electrically conductive and electrically insulated. [0003] 2. Description of the Related Art [0004] A metal-ceramic layered compact which is heat resistant and heat dissipating is disclosed in, for example, Japanese Unexamined Patent Application Publication No. 5-286776, as d...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B22F7/02H10N10/01H10N10/13H10N10/817
CPCB22F7/02B22F2998/10H01L35/08H01L35/34B22F1/0096B22F3/105H10N10/817H10N10/01B22F1/148
Inventor ICHIKAWA, JUN-ICHISHIKATA, HIDEOSAITO, SHIGEYUKIISHIHARA, CHIOSHIBATA, MASAKIIWAKIRI, MAKOTO
Owner HITACHI POWDERED METALS COMPANY
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