JP4379798B2 - Method for producing metal-ceramic sintered laminate - Google Patents

Description

  The present invention relates to a method for producing a metal-ceramic laminate having both heat resistance and thermal conductivity, or electrical insulation, electrical conductivity, and thermal conductivity and exhibiting thermal stress relaxation by powder metallurgy. For example, the laminate is suitably used as a thermal stress relaxation pad for a thermoelectric conversion element.

  As this type of metal-ceramic laminate, as disclosed in Patent Document 1, a metal layer (copper, nickel, tungsten, etc.) and a ceramic layer (alumina, aluminum nitride, boron nitride, etc.), Some have an intermediate layer of mixed components of ceramics, and the intermediate layer changes stepwise or continuously. In such a laminate, a layer containing a metal is laminated on a ceramic substrate by thermal spraying, or after printing and pasting a paste, and then hot pressing, HIP (hot isostatic pressing), or a molded body. It is manufactured by applying a direct voltage to sinter by an electric heating method that causes discharge plasma between particles.

  Patent Document 2 describes a structure in which an intermediate layer containing a large amount of silver-copper alloy is formed between an alumina substrate and a copper plate, including tungsten, silver-copper alloy, and titanium. Yes. The intermediate composition is laminated by printing a paste, and sintering is performed in a vacuum or in an atmosphere of nitrogen gas, hydrogen gas, or argon gas.

Japanese Patent Laid-Open No. 5-286767 JP-A-6-329480

  The above prior art is obtained by laminating a metal layer on a previously sintered ceramic substrate by thermal spraying or paste printing, and then sintering the metal layer. In terms of quality, the strength of the ceramic is high, and the metal layer It is said that the thermal conductivity is also good because it is dense. However, in such a manufacturing method, after firing ceramics at a high temperature, metal-containing powders having different compositions are sequentially sprayed, and printing and drying of the paste material are repeated. It is long and cumbersome. Therefore, a method that can be more easily manufactured is desired. Further, the lower the sintering temperature, the better from the viewpoint of energy saving, but this point is not satisfactory.

  Accordingly, an object of the present invention is to provide a production method that can reduce the number of steps and keep the sintering temperature lower than in the prior art in producing a metal-ceramic sintered laminate.

In the present invention, two types of copper powder and alumina powder, two types of mixed powder of copper powder, copper powder and alumina powder, or three types of mixed powder of copper powder, copper powder and alumina powder and alumina powder are molded. A method for producing a metal-ceramic sintered laminate in which a metal mold is laminated and compressed and compression-molded, and the resulting compression-molded body is sintered at a temperature lower than the melting point of copper, in order to form at least a ceramic layer In the alumina powder, bismuth oxide alone is added to and dispersed in the alumina powder at a ratio of 0.1 to 5.0% by mass , and sintering is performed using a microwave sintering furnace or an electrothermal sintering furnace. After performing in an inert gas atmosphere, the obtained sintered body is heated in a reducing gas atmosphere at a temperature of 400 to 600 ° C., or a temperature of 600 ° C. or lower in the cooling process of sintering is reduced. to hold in a gas atmosphere It is characterized by a door. When the above powders are compression molded and sintered, the copper powder forms a metal layer, the mixed powder of copper powder and alumina powder forms a mixed layer, and the alumina powder forms a ceramic layer. These layers are joined together. The

  In the present invention, the compression molded body is sintered using a microwave sintering furnace or an electrothermal sintering furnace, and the content of bismuth oxide with respect to the alumina powder is appropriately determined depending on the sintering furnace used. It is recommended to change. That is, the content of bismuth oxide when using a microwave sintering furnace is set to 0.1 to 1.5 mass%, and the content of bismuth oxide when using an electrothermal sintering furnace is 1.5 to 5. Set to 0% by weight.

  The microwave sintering furnace is a type that heats and heats the workpiece exclusively by microwave, and a type that heats the inside of the furnace with radiant heat from an electric heater and irradiates the workpiece with microwaves from an appropriate temperature. In the furnace, a wall portion made of silicon carbide or the like that is heated by being irradiated with microwaves is provided, and the workpiece is heated by radiant heat from the wall portion and direct irradiation of the microwave. Any of these microwave sintering furnaces can be used in the present invention. The electrothermal sintering furnace is an ordinary sintering furnace such as a powder belt metal mesh belt type or pusher type equipped with an electric heater. The furnace atmosphere of the microwave sintering furnace and the electrothermal sintering furnace is preferably an inert atmosphere or a reducing atmosphere. The melting point of bismuth oxide is about 820 to 860 ° C., but the sintering temperature is lower than the melting point of copper (1083 ° C.) and can be performed at 1000 to 1050 ° C. When heating for dewaxing is performed before sintering as necessary, heating in an atmosphere containing oxygen is desirable.

  The alumina powder for forming the ceramic layer used in the present invention is the one in which bismuth oxide is added to the alumina powder as described above, but the granulation is made of alumina powder itself or a mixture of alumina powder and bismuth oxide powder. It is preferable to contain powder. The alumina powder for forming the mixed layer of copper alumina is preferably added with bismuth oxide, but can also be implemented without bismuth oxide. Also in these forms, it is preferable to use granulated powder made of alumina powder itself or a mixture of alumina powder and bismuth oxide powder.

  The layer structure of the metal-ceramic sintered laminate obtained in the present invention is appropriately selected depending on the equipment to be applied, the required function, and the like. In particular, when laminating the above three kinds of powders, a layer structure of at least a metal layer made of copper powder, a mixed layer made of mixed powder, and a ceramic layer made of alumina powder is generally used from one surface in the lamination direction. Based on this, a sandwich layer structure in which a ceramic layer is disposed as a central layer, a mixed layer as an intermediate layer, and a metal layer as an outermost layer is disposed on both sides thereof.

  Such a layer structure includes one having a plurality of mixed layers. Each mixed layer in that case has a configuration in which the mixing ratio of the copper powder and the alumina powder in the mixed powder is inclined so that the content of the copper powder decreases in the stacking order from the metal layer side to the ceramic layer side. It is suitable when applied to a thermal stress relaxation pad.

Next, specific examples of individual materials and manufacturing methods used in the present invention will be described in detail.
[1] Copper powder In the metal-ceramic sintered laminate of the present invention, the copper powder forms the outermost metal layer having both electrical conductivity and thermal conductivity. The copper powder has good compressibility, but in order to facilitate filling into a molding die, a copper powder having a particle size passing through a 100 mesh sieve is preferably used. When a fine powder is used, the powder fluidity can be improved by granulation. The copper powder is preferably electrolytic copper powder.

[2] Alumina (Al ₂ O ₃ ) powder The alumina powder forms a ceramic layer excellent in electrical insulation and thermal conductivity in the metal-ceramic sintered laminate of the present invention. The raw material powder forming the ceramic is preferably as fine as possible by compression molding and has good sinterability. As the particle size of the alumina powder, those having an average particle size of about 0.2 μm and a secondary particle size after aggregation of about 1 to 20 μm are preferably used. If the powder fluidity is inferior due to the small particle size, granulation using a binder such as carboxymethylcellulose (CMC) improves the fluidity of the powder and facilitates the filling of the powder into the molding die. And the strength of the molded body is high, which is preferable. The particle size of the granulated powder is adjusted to 150 μm or less.

[3] Bismuth oxide (Bi ₂ O ₃ )
The bismuth oxide added to the alumina powder becomes a liquid phase around 825 ° C., and promotes the sintering of the alumina powder. In the present invention, bismuth oxide is contained in an amount of 0.1 to 5.0% by mass with respect to the alumina powder, but a more desirable range is 0.1 to 2.0% by mass. When the content is less than 0.1% by mass, only a small effect is obtained. On the other hand, if it exceeds 5.0% by mass, blowout or erosion occurs from alumina depending on the sintering conditions (heating mode, atmosphere, etc.). The content for reliably suppressing these problems and obtaining the effect of inclusion is preferably 2.0% by mass or less in the above range. Bismuth oxide is added to the alumina powder as a powder. The particle diameter of the powder is preferably as fine as the alumina particle diameter, and the secondary particle diameter is preferably 30 μm or less. The mixed powder of alumina powder and bismuth oxide is preferably granulated and used in the same manner as the alumina powder.

[4] Mixed powder The mixed powder of the above copper powder and alumina powder forms a mixed layer in the metal-ceramic sintered laminate of the present invention. The mixed layer is used, for example, as an intermediate layer between a metal layer made of copper powder and a ceramic layer made of alumina powder. As for the mixing ratio of the copper powder and the alumina powder, for example, a volume ratio of copper and alumina after sintering may be 1: 1. When a plurality of mixed layers are formed as the intermediate layer, a combination of a mixed layer with a large amount of copper powder toward the metal layer side and a mixed layer with a large amount of alumina powder toward the ceramic layer side is desirable. That is, the layer structure is inclined so that the content of the copper powder decreases in the stacking order from the metal layer side to the ceramic layer side.

  The mixed powder contains copper, and this copper has a function of promoting the sintering by joining the alumina particles during the sintering. In particular, in a copper-alumina mixture having a high copper content, a sintered body having a high density and strength can be obtained without adding bismuth oxide. Of course, it is preferable to add bismuth oxide to the mixed powder. In this case, the addition amount of bismuth oxide is 0.1 to 5.0% by mass with respect to the alumina powder. Also in the case of mixed powder, it is preferable to use granulated powder made of alumina powder itself or a mixture of alumina powder and bismuth oxide powder.

[5] Binder In the present invention, as a means for granulating the alumina powder or the mixed powder of the alumina powder and the bismuth oxide powder as described above, various binders can be mixed with these powders. A compression-molded body of alumina powder can obtain a strength that can be handled by adjusting the particle size distribution of the alumina powder, but methyl cellulose (MC), polyvinyl alcohol (PVA), ammonium alginate, carboxymethyl cellulose (CMC), polyvinyl When a binder such as pyrrolidone (PVP) is mixed or added as a granulating binder, the strength can be further increased. As a result, cracks and defects can be made difficult to occur when transported in the powder molding and sintering processes. Although it can be produced without using a binder, it is desirable to improve the powder flowability by granulation in order to improve the mold filling property.

  The binder disappears by heating during sintering. However, the addition of a large amount lowers the density of the sintered alumina ceramics and deteriorates the thermal conductivity. An addition amount of about 0.1 to 0.3% by mass is desirable. Examples of the granulation method using the binder include a method in which alumina powder is mixed with an aqueous solution in which the binder is mixed with water, and then the mixture is granulated by a spray drying (spray drying) method or the like.

[6] Molding Lubricant When the binder of the alumina powder is PVA, molding can be performed without using a molding lubricant. A molding lubricant can be used to make it easier. Binders such as CMC are inferior in lubricity, so a molding lubricant is necessary. As the molding lubricant, zinc stearate, lithium stearate, ethylene bisstearamide, or the like is used, and it is mixed in the mixed powder or applied to the inner wall of the molding die as necessary. In order to apply the molding lubricant, there are methods of applying electrostatically applied or liquid dispersed.

[7] Laminated structure The laminated structure consists of “metal layer (copper powder) -ceramic layer (alumina powder)”, “metal layer-mixed layer (mixture of copper powder and alumina powder) in order from one surface in the lamination direction. Examples thereof include: (by powder) -ceramic layer "," metal layer-mixed layer-ceramic layer-mixed layer "," metal layer-mixed layer-ceramic layer-mixed layer-metal layer ", and the like.

  Since the ceramic layer is relatively inferior in thermal conductivity, it is desirable to make it thin. However, if it is too thin, layers containing adjacent metals are likely to coexist and electrical insulation may be reduced. The thickness of the ceramic layer is preferably about 0.5 to 2 mm. When a mixed layer is included, a plurality of the mixed layers may be formed. When there are a plurality of mixed layers, as described above, the mixing ratio of the copper powder and the alumina powder in the mixed powder is inclined so that the content of the copper powder decreases in the stacking order from the metal layer side to the ceramic layer side. The configuration is desirable.

[8] Stacking of powder In order to fill each powder into a molding die composed of a die for shaping the outer shape of the molded body and upper and lower punches, a powder feeder that advances and retreats toward the die cavity can be used. In the powder feeder, a plurality of powder boxes are combined in the advancing and retreating direction. For example, when the laminated structure is “metal layer—mixed layer 1 layer—ceramic layer—mixed layer 1 layer—metal layer”, three powder boxes From the front, copper powder, a mixed powder of copper powder and alumina powder, and alumina powder are loaded. When the lower punch is flush with the top surface of the die, the powder feeder is advanced to stop the powder box containing copper powder on the lower punch, and the lower punch or die is moved to form a cavity to fill the copper powder. Is done. Next, the mixed powder is moved onto the die cavity and filled in the same manner. After the alumina powder is filled in the same manner, five layers can be stacked and filled while the powder feeder is sequentially retracted.

  In the above filling method, a powder feeder structure having a space between a plurality of powder boxes is used, and after filling one kind of powder, the filled powder is lowered from the die surface in a state where the space is stopped on the cavity. In addition to forming a cavity, scraping off the filling powder adhering to the wall surface of the die cavity with a simple punch attached to the upper punch or feeder from the space, a compression molded body having a more divided laminated structure is obtained. Obtainable.

  Since the surface of each filled powder is microscopically uneven, it forms a mixed state with a few parts of adjacent powder. The same applies to the mixed layer and the ceramic layer, and the composition of each layer is not clearly separated, and the layers are intertwined, so that the layers are difficult to peel off.

[9] Compression molding of powder The copper powder has a density ratio of 95% or more at a molding pressure of about 100 to 300 MPa, and has good electrical and thermal conductivity. On the other hand, the alumina powder has a density ratio of about 50% at a molding pressure of about 600 MPa and about 60% at 700 MPa, and the density rises slowly at molding pressures higher than this. Therefore, the molding pressure of the laminated and filled powder is preferably about 600 to 1000 MPa.

[10] When using a sintering / microwave sintering furnace As a microwave sintering furnace, for example, an electric heater provided on the inner wall of a heating chamber as described in JP-A-6-345541 is available. , Since preheating and cooling can be controlled, it is preferably used. Further, a radiation-type microwave sintering furnace in which the inner wall portion of the heating chamber is made of a material having a high dielectric constant at room temperature such as silicon carbide is also preferably used. According to this radiation-type microwave sintering furnace, silicon carbide has a high dielectric constant during the temperature rising process, and the temperature of the alumina is increased by radiant heat from the heated silicon carbide. Since the dielectric constant of alumina decreases and the dielectric constant of alumina increases, the alumina is heated by microwaves that cannot be absorbed by silicon carbide.

  The furnace atmosphere during sintering is an inert atmosphere or a reducing atmosphere. The inert atmosphere gas may be nitrogen, and the reducing atmosphere gas may be a mixed gas of hydrogen and nitrogen. When the compression molded body is sintered using a microwave sintering furnace, the content of bismuth oxide in the alumina powder is set to 0.1 to 1.5 mass%. When microwaves are irradiated to a heated compression molded body, there is an advantage that sintering is promoted rather than heating with an electric heater.

-When using an electrothermal sintering furnace Even when an electrothermal sintering furnace equipped with an electrothermal heater or the like is used, the atmosphere in the furnace is an inert atmosphere or a reducing atmosphere. The content of bismuth oxide in the alumina powder when using an electrothermal sintering furnace is set to 1.5 to 5.0 mass%.

  In the present invention, the compression-molded body is heated and sintered in any of the above-mentioned sintering furnaces. In particular, when performed in a reducing atmosphere, bismuth oxide in alumina is preferentially reduced to metal bismuth. . This phenomenon impedes the sintering of alumina, or liquefied bismuth in alumina causes cracks in the sintered body during the cooling process after sintering. In order to avoid this, the introduction timing of the reducing gas is required to be 800 ° C. or lower, preferably 600 ° C. or lower.

  In view of this, it is desirable to perform sintering in an inert gas atmosphere such as nitrogen gas, regardless of whether a microwave sintering furnace or an electrothermal sintering furnace is used. In addition, in any of the sintering furnaces, heating is performed in an inert gas atmosphere such as nitrogen gas at a temperature exceeding 600 ° C., and reduction of a mixed gas of nitrogen and hydrogen is performed at a temperature of 600 ° C. or lower. A method of heating in a reactive gas atmosphere can be employed. According to the latter method, bismuth oxide is not reduced during sintering, and the oxidized copper is reduced and sintered as in a gas atmosphere containing oxygen in the course of heating to promote dewaxing. The ligature can be cleaned. In place of the latter method, the same effect can be obtained by performing sintering in an inert gas atmosphere, cooling, and heating the sintered body at 400 to 600 ° C.

Further, in the sintering process, the compression molded body is heated while applying a load in the powder lamination direction, or the compression molded body is buried in alumina powder having a particle size coarser than that of the alumina powder forming the ceramic layer. You may heat in the state. By performing the sintering while applying a load, it is possible to suppress problems such as peeling and cracking of each layer. The load may be appropriately selected from a range of, for example, about 10 to 200 g / cm ² , and an excessive load beyond this is not preferable because it causes crushing. Sintering in the state of being buried in alumina powder is effective because it induces effective resistance to thermal expansion of each layer. The reason why the alumina powder having a particle diameter larger than that of the alumina powder forming the ceramic layer is used for burying is to prevent the alumina powder from being sintered.

  During sintering, dewaxing may be performed to remove oil in the compression molded body at the initial stage of heating. In consideration of dewaxing, the binder should be added in a small amount, and a polymer component such as PVA having a low polymerization degree is preferable. This is because if the addition amount is low, the expansion amount of degassing during sintering is reduced, and even if the heating rate from dewaxing to sintering is high, burning cracks are unlikely to occur. With regard to baked cracks, the temperature uniformity of the compression-molded product is also involved, so it cannot be said unconditionally. However, by adjusting the polymer component to 1% by mass or less, the temperature rise during dewaxing is 60 times the normal temperature. Even if it is about 3 ° C./min or more, no problem occurs. Note that in the dewaxing process, the atmosphere in the furnace preferably contains oxygen.

  In the present invention, two types of copper powder and alumina powder, or a mixed powder of copper powder and copper powder and alumina powder and three types of alumina powder are stacked and filled in a molding die, and compression molding is performed. A method for producing a sintered metal-ceramic laminate in which a formed body is sintered at a temperature lower than the melting point of copper, wherein 0.1 to 5.0 mass of bismuth oxide is added to the alumina powder in the alumina powder. It is essential to add at a rate of%. As a result, in producing a metal-ceramic sintered laminate, the number of processes is reduced, and the sintering temperature can be suppressed lower than before.

Next, embodiments of the present invention will be described with reference to the drawings.
FIGS. 1A to 1E are cross-sectional views showing metal-ceramic sintered laminates 5A to 5E, respectively, in which the metal layer is mainly composed of copper powder and the ceramic layer is mainly composed of alumina powder. .

  A sintered laminate 5A shown in FIG. 1A has a two-layer structure in which a ceramic layer 1 is laminated on a metal layer 3, the metal layer 3 is an electrolytic copper powder, and the ceramic layer 1 is 0.1 to 0.1% alumina powder. The powder which mixed 1.5 mass% bismuth oxide is used. In order to manufacture the sintered laminated body 5A, first, these powders are sequentially stacked and filled in a molding die with a predetermined thickness, and compression molded at a molding pressure of about 800 MPa to obtain a compression molded body. Next, the compression molded body is placed in a microwave sintering furnace, the inside of the furnace is set to a nitrogen gas (inert gas) atmosphere, and the microwave is irradiated to the compression molded body to heat the ceramic layer 1 at about 1030 ° C. for 30 minutes. Cool after heating for minutes. This primary sintered body is re-sintered at 500 ° C. in a mesh belt sintering furnace in an ammonia decomposition gas atmosphere to obtain a sintered laminate 5A.

  This sintered laminate 5A is used, for example, as a heat radiating member. In that case, the ceramic layer 1 is brought into contact with a ceramic product or ceramic member whose temperature has been increased, and the metal layer 3 is provided with a heat radiating fin. Form is taken. In addition, when the metal layer 3 is required to have thermal conductivity and electrical conductivity and the ceramic layer 1 is required to have electrical insulation, the metal layer 3 is brought into contact with the side where electrical conductivity is required, so that the electrical insulation is achieved. The ceramic layer 1 is used in contact with the required side. In the case of this sintered laminate 5A, since it is composed of the metal layer 3 and the ceramic layer 1, the interlayer is peeled off due to the difference in thermal expansion when used at a high temperature. It is used at a relatively low temperature.

  Hereinafter, the sintered laminates 5B to 5E shown in FIGS. 1B to 1E will be described. The sintering method is the same as that of the sintered laminate 5A. The following mixed layer (intermediate layer) is composed of a mixed powder of copper powder and alumina powder.

  A sintered laminate 5B shown in FIG. 1B has a structure in which two mixed layers 21 and 23 having different compositions are sandwiched and laminated between a metal layer 3 and a ceramic layer 1. The mixed layer 23 on the metal layer 3 side is formed of a mixed powder in which alumina powder and copper powder are mixed at a mass ratio of 15:85 (alumina volume ratio is about 30%), and the mixed layer 22 on the ceramic layer 1 side is It is formed of a mixed powder obtained by mixing alumina powder and copper powder at a mass ratio of 30:70 (alumina volume ratio is about 50%). That is, the mixed layer 23 on the metal layer 3 side has a high copper content, and the mixed layer 22 on the ceramic layer 1 side has a high ceramic content. This sintered laminate 5B has an advantageous structure as compared with the sintered laminate 5A of FIG. 1 (a) in that it can relieve the thermal stress caused by the surrounding temperature change and the heat cycle to which repeated thermal shocks are applied. ing.

  A sintered laminate 5C shown in FIG. 1C has a structure in which a ceramic layer 1 is sandwiched and laminated between two metal layers 3a and 3b. The metal layers 3a and 3b have thermal conductivity and electrical conductivity, and the intermediate ceramic layer 1 has electrical insulation. Therefore, the metal layer 3 a and the metal layer 3 b are electrically insulated by the ceramic layer 1. The sintered laminate 5C is used, for example, such that one metal layer 3a side is heated and the other metal layer 3b side is radiated to bear cooling. The sintered laminate 5C is preferably used in an environment with a relatively low temperature or a small temperature difference because the ceramic layer 1 and the metal layers 3a and 3b are in direct contact with each other, so that the thermal shock resistance may be insufficient.

  A sintered laminate 5D shown in FIG. 1 (d) has a structure in which the mixed layers 22a and 22b are sandwiched between the ceramic layer 1 and the metal layers 3a and 3b in the structure of the sintered laminate 5C. This is the structure. Each of the mixed layers 22a and 22b has an alumina volume ratio of about 50%.

  The sintered laminate 5E shown in FIG. 1 (e) has a mixed layer 21a, 21b (alumina volume ratio is between the mixed layers 22a, 22b and the ceramic layer 1 in the structure of the sintered laminate 5D. About 70%), and sandwiched between the mixed layers 22a and 22b and the metal layers 3a and 3b with the mixed layers 23a and 23b (alumina volume ratio is about 30%), respectively. The mixed layer between 1 and the metal layers 3a and 3b is three layers. Like these sintered laminated bodies 5D and 5E, by sandwiching the mixed layer between the ceramic layer 1 and the metal layers 3a and 3b, the thermal stress is relieved and the thermal shock resistance is excellent.

  Next, specific examples of use of the sintered laminates 5A to 5E will be described with reference to FIGS. 2A and 2B, reference numeral 5 indicates any one of the sintered laminates 5 </ b> A to 5 </ b> E.

  In FIG. 2A, a plurality of N-type elements and P-type elements are alternately arranged, and each thermoelectric element 8 is connected in series by a sintered laminate 5, and the whole is fixed to both ends. A cross section of a thermoelectric conversion module 6A having a structure sandwiched by a good metal plate (for example, a copper plate, hereinafter referred to as a copper plate) 7 is shown. The sintered laminate 5 is used as a thermal stress relaxation pad. According to this thermoelectric conversion module 6A, power is obtained from a terminal attached to the terminal thermoelectric element 8 by applying heat to one end and cooling the other end. Such a thermoelectric conversion module 6A is attached and used in a state of being sandwiched between a heat radiation part such as a furnace and a cooling means such as a water jacket.

  In the thermoelectric conversion module 6A of FIG. 2 (a), the thermoelectric element 8 and the sintered laminate 5 are joined together by solder or graphite paint, thereby ensuring electrical and thermal conductivity between the two, and sintering. The laminated body 5 and the copper plate 7 are joined by solder, graphite paint, water glass, refractory glass, or the like, thereby ensuring thermal conductivity. The thermoelectric conversion module 6B of FIG. 2B has the same basic configuration as the thermoelectric conversion module 6A, but the state in which the respective members are stacked and abutted is a bolt 10 and a nut for fastening two copper plates 7 together. 11 is held.

  The sintered laminates 5A to 5E can be used as the sintered laminate 5 used in the thermoelectric conversion modules 6A and 6B, and the sintered laminates 5D and 5E are particularly preferable. The metal layers 3a and 3b have good conductivity and thermal conductivity, the ceramic layers 1 electrically insulate the metal layers 3a and 3b, and the mixed layers (21a, 22a, and 23a) have a high temperature side and a low temperature side. This is because the thermal stress due to the thermal expansion difference and the thermal stress caused by the heat cycle can be relaxed, and the power generation performance and reliability are improved.

(A)-(e) is sectional drawing which shows the example of the laminated structure of the metal-ceramics sintered laminated body which concerns on embodiment of this invention. (A), (b) is sectional drawing which shows the example which applied the metal-ceramics sintered laminated body of embodiment to the thermoelectric conversion module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ceramics layer 3, 3a, 3b ... Metal layer 5 (5A-5E) ... Metal-ceramics sintered laminated body 21, 21a, 22a, 23, 23a ... Mixed layer

Claims (5)

Two kinds of copper powder and alumina powder, two kinds of mixed powder of copper powder, copper powder and alumina powder, or three kinds of mixed powder of copper powder, copper powder and alumina powder and alumina powder are laminated on the mold. A method for producing a metal-ceramic sintered laminate, comprising filling and compression molding, and sintering the obtained compression molded body at a temperature lower than the melting point of copper,
In the alumina powder for forming at least a ceramic layer, bismuth oxide is added and dispersed in a proportion of 0.1 to 5.0% by mass with respect to the alumina powder ,
After the sintering is performed in an inert gas atmosphere using a microwave sintering furnace or an electrothermal sintering furnace, the obtained sintered body is heated at a temperature of 400 to 600 ° C. in a reducing gas atmosphere. Alternatively, a method for producing a metal-ceramic sintered laminate , wherein a temperature of 600 ° C. or lower in the cooling process of the sintering is maintained in a reducing gas atmosphere .   The sintering is performed using a microwave sintering furnace or an electrothermal sintering furnace, and the content of the bismuth oxide with respect to the alumina powder is set to 0.1 to 1 when the microwave sintering furnace is used. The method for producing a metal-ceramic sintered laminate according to claim 1, wherein when the electrothermal sintering furnace is used, the content is set to 1.5 to 5.0 mass%. The method for producing a metal-ceramic sintered laminate according to claim 1 or 2 , wherein the alumina powder or a mixture of the alumina powder and the bismuth oxide powder is a granulated powder. From one side of the stacking direction, at least, a metal layer by the copper powder, the mixed layer by mixing powder according to any one of claims 1 to 3, characterized in that the ceramic layer by the alumina powder is formed Method for producing a metal-ceramic sintered laminate. It has a plurality of the mixed layers, and the mixing ratio of the copper powder and the alumina powder in the mixed layers is such that the content of the copper powder decreases in the stacking order from the metal layer side to the ceramic layer side. It inclines, The manufacturing method of the metal-ceramics sintered laminated body of Claim 4 characterized by the above-mentioned.

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