JP5526938B2 - Method for producing porous aluminum sintered body - Google Patents

Description

  The present invention is a heat transfer member such as a heat sink, a heat pipe, various filters, a catalyst carrier, a lightweight structural member, a silencer damping material, a heat insulating material, an electromagnetic wave shielding material, etc. The present invention relates to a method for producing another three-dimensional irregularly shaped aluminum porous sintered body.

Conventionally, as a porous metal plate constituting a heat transfer component of a heat storage device, a condensate trap member of a filter or a fuel cell condensing and collecting device, or a heat sink used for heat radiation, generally an open pore type nickel-based material or Stainless steel foam metal is often used.
By the way, if an aluminum-based porous plate can be used as the porous metal plate, it is possible to improve the thermal conductivity and reduce the weight of the apparatus.

  On the other hand, for example, in Patent Document 1 below, after adding a thickener to molten aluminum to increase the viscosity, titanium hydride as a foaming agent is added, and hydrogen gas generated by a thermal decomposition reaction of titanium hydride is added. There has been proposed a production method for obtaining a porous aluminum body by a foam melting method in which molten aluminum is solidified while being foamed.

  However, as the porous metal plate used for the heat sink or the like, as long as the circulation of gas or liquid is ensured, the pore diameter is preferably small, whereas the foam obtained by the conventional foam melting method is used. Since aluminum has large closed pores of several mm, there is a problem that it cannot be put into practical use.

  On the other hand, the inventors of the present invention, as Japanese Patent Application No. 2009-82498, mixed aluminum powder with a sintering aid powder containing titanium as a sintering aid element to obtain an aluminum mixed raw material powder. A slurry-like viscous composition containing pores is obtained by adding a water-soluble resin binder and water to the mixed raw material powder, and the viscous composition is formed into a pre-sintered body by a slurry method such as a doctor blade method. Tm-10 (° C.) ≦ T ≦ 685 (° C.), where T m (° C.) is the temperature at which the aluminum mixed raw material powder starts melting in a non-oxidizing atmosphere. The manufacturing method of the aluminum porous sintered compact which manufactures the aluminum porous sintered compact by heat-baking at (degreeC) was proposed.

  According to the above method for producing a porous aluminum sintered body, it is possible to easily obtain an aluminum porous sintered body having a three-dimensional skeleton structure in which extremely small pores having a pore diameter of 600 μm or less are formed and having an open pore type. There is an advantage that you can.

Japanese Patent Application Laid-Open No. 08-209265

  However, in the method for producing the porous aluminum sintered body, since the viscous composition is dried and sintered by the slurry method, a thin plate member of about 5 mm or less can be easily obtained. There is a problem that it is not possible to obtain a thick plate-like aluminum porous sintered body having a thickness of several centimeters, a block shape, a cylindrical shape, or other three-dimensional irregularly shaped aluminum porous sintered bodies. there were.

  The present invention has been made in view of such circumstances, and has an open pore type aluminum porous sintered body having various shapes such as a thick plate shape, a block shape or a cylindrical shape having a three-dimensional skeleton structure with a small pore diameter. It is an object of the present invention to provide a method for producing an aluminum porous sintered body that can be produced easily and reliably.

In order to solve the above-mentioned problems, a method for producing an aluminum porous sintered body according to claim 1 includes an aluminum mixed raw material powder containing titanium powder and / or titanium hydride powder as a sintering aid in aluminum powder, water And a viscous composition preparation step for obtaining a viscous composition containing bubbles by mixing a water-soluble resin binder, and pre-sintering by filling the viscous composition into a container having a predetermined shape, and freezing and drying. Tm-10 when the pre-sintering step for obtaining a body and the temperature before the aluminum mixed raw material powder starts melting in an inert atmosphere or vacuum is Tm (° C.). (℃) ≦ T ≦ 685 becomes to have a firing step of firing at a temperature T of the (℃) (℃), and the average particle diameter of the sintering aid powder r (μm), the sintered Yuisuke The mixing ratio of the powder When the mass%, 1 (μm) ≦ r ≦ 30 (μm), 1 is ≦ W ≦ 20 (mass%), and those with 0.1 ≦ W / r ≦ 2 der wherein Rukoto It is.

  The invention according to claim 2 is the invention according to claim 1, wherein in the pre-sintering step, the pressure is reduced to a pressure larger than the pressure at which the viscous composition boils and lower than the atmospheric pressure, and mixed. In addition to increasing the size of the bubbles, the viscous composition is frozen in the reduced pressure state.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the pre-baking step is performed at a temperature of 0.1 ° C. or more and 10 ° C. or less higher than the freezing temperature of the viscous composition. And then freezing the viscous composition after holding for 1 to 60 minutes.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the aluminum powder has an average particle diameter of 2 to 200 μm.

The invention according to claim 5 is the invention according to any one of claims 1 to 4 , wherein the water-soluble resin binder is within a range of 0.1% to 7% of a mass of the aluminum mixed raw material powder. It is characterized by being included.

The invention according to claim 6 is the invention according to any one of claims 1 to 5 , wherein in the viscous composition preparation step, an interface within a range of 0.02 to 3% of the mass of the aluminum mixed raw material powder. An activator is added.

According to the invention according to any one of claims 1 to 6 , the viscous composition obtained in the viscous composition preparation step is formed into a bottomed cylindrical or box-like container or split mold having a predetermined product shape. Filling and freezing and drying the viscous composition to form a pre-sintered shaped body of a thick plate shape, block shape, cylindrical shape, etc., and in the inert atmosphere or vacuum, the aluminum When the temperature at which the mixed raw material powder starts to melt is Tm (° C.), it is heated and fired at a temperature T (° C.) of Tm−10 (° C.) ≦ T ≦ 685 (° C.), thereby reducing the pore diameter to 600 μm or less. An open pore type aluminum porous sintered body having a three-dimensional skeleton structure in which pores are formed and having 20 or more pores per linear length of 1 cm, and having the above product shape Or block aluminum It can be obtained porous sintered body.

Here, the reason for limiting the heating and firing temperature to Tm-10 (° C) or higher is that the temperature at which the aluminum powder contained in the aluminum mixed raw material powder and the sintering aid powder containing titanium start the reaction is Tm-10 (° C). That's why. The temperature at which the aluminum mixed raw material powder starts melting is described as Tm because the pure aluminum melting point is 660 ° C., but since aluminum used industrially contains iron or silicon as an impurity, the melting point This is because the temperature becomes lower than 660 ° C. On the other hand, the reason why the heating and firing temperature is limited to 685 ° C. or less is that when heated and held at a temperature higher than that temperature, a drop-shaped lump of aluminum is generated in the sintered body.

  At this time, as in the invention described in claim 2, in the pre-sintering step, if the pressure is reduced to a pressure higher than the boiling pressure of the viscous composition and lower than the atmospheric pressure, it is mixed. When the bubbles expand and become large and adjacent bubbles communicate with each other, a three-dimensional skeleton structure can be easily constructed.

  Furthermore, as in the invention according to claim 3, in the pre-baking step, the viscous composition is held at a temperature of 0.1 ° C. or higher and 10 ° C. or lower than the freezing temperature for 1 to 60 minutes. By doing so, it is possible to stabilize the internal bubbles and to prevent the bubbles from escaping to the outside because the viscosity of the viscous composition is higher than that at room temperature.

  The aluminum powder preferably has a particle size such that the viscous composition is viscous enough to be molded into a desired shape. That is, when the average particle size is reduced, the mass of the water-soluble resin binder needs to be increased by increasing the mass of the water-soluble resin binder relative to the mass of the aluminum powder. When the pre-sintered shaped body is heated and fired, the amount of carbon remaining in the aluminum increases and the sintering reaction is hindered.

  On the other hand, when the particle diameter of the aluminum powder is too large, the strength of the porous sintered body is lowered. Therefore, as in the invention described in claim 4, preferably, the average particle diameter of the aluminum powder is set to 2 μm or more to prevent the inhibition of the sintering reaction by increasing the mass of the water-soluble resin binder, and to 200 μm or less. Ensuring the strength of the porous sintered body. More preferably, the average particle diameter of the aluminum powder is 7 μm to 40 μm.

Furthermore, in the present invention, the sintering aid powder has an average particle diameter r and a blending ratio W mass% of 1 (μm) ≦ r ≦ 30 (μm), 0.1 (mass%) ≦ W ≦ 20 (mass). %), and 0.1 ≦ W / r ≦ 2.
This is because when the mixing ratio W of the sintering aid powder exceeds 20% by mass, the sintering aid powder has contact points in the aluminum mixed raw material powder, and the reaction heat of aluminum and titanium cannot be controlled. At the same time, a desired porous sintered body cannot be obtained, so 0.1 (mass%) ≦ W ≦ 20 (mass%).

  Further, even within the range of 0.1 (mass%) ≦ W ≦ 20 (mass%), the reaction heat of aluminum and titanium may become too large depending on the particle size of the sintering aid powder, In some cases, the temperature of the aluminum melted by heat is further increased, the viscosity is lowered, and droplets are generated.

  Therefore, from the results of observing specimens prepared under various conditions with an electron microscope, the surface layer with a substantially constant thickness from the exposed surface side of the titanium particles within a range in which the calorific value can be controlled by the blending amount and particle size of titanium. It was found that only the part reacted with aluminum. Thus, it was experimentally derived that it is desirable that 1 (μm) ≦ r ≦ 30 (μm) and 0.1 ≦ W / r ≦ 2 in order to prevent the generation of droplets.

The meaning of 0.1 ≦ W / r ≦ 2 will be described below when titanium is used as the sintering aid powder. The average particle diameter of titanium is r, the number of titanium particles is N, and the titanium Assuming that the added mass is w, the specific gravity of titanium is D, and the amount of decrease in the titanium particle size due to the reaction with aluminum is d, the amount of heat of reaction Q is proportional to the volume of the reacted titanium, so Q∝4πr ² dN. Furthermore, since the addition amount of the titanium particles is calculated by the product of the average volume of one titanium particle and the number of titanium particles, w = 4 / 3πr ³ DN. Therefore, when the latter equation is substituted into the former equation, Q∝3wd / rD is obtained. Here, Q∝w / r from the observation result that 3 / D is a constant and d is substantially constant regardless of the sintering conditions. Therefore, by experimentally determining the range of W / r in which no droplets are generated and limiting it as described above, the generation of droplets due to excessive reaction heat between aluminum and titanium is prevented.

Further, when the water-soluble binder is contained in excess of 7% of the mass of the aluminum mixed raw material powder, the amount of carbon remaining in the pre-sintered molded body during heating and firing is increased, and the sintering reaction is caused. Be inhibited. On the other hand, if it is less than 0.5%, the handling strength of the green body before sintering cannot be ensured. For this reason, it is preferable to be contained within the range of 0.5% to 7% of the mass of the aluminum mixed raw material powder as in the invention described in claim 5 .

In addition to this, by adding a surfactant to the aluminum mixed raw material powder as in the invention described in claim 6 , bubbles can be generated effectively, and the amount of the surfactant added is mixed with aluminum. By making it 0.02% or more of the mass of the raw material powder, the effect due to the addition of the surfactant can be obtained, and by making it 3% or less, the amount of carbon remaining in the pre-sintered molded body increases This can prevent the sintering reaction from being hindered.

It is a longitudinal cross-sectional view which shows the bubble nucleus formation apparatus used in order to carry out the bubble formation in the viscous composition in one Embodiment of this invention. The viscous composition preparation process in the said embodiment is shown, (a) is the state with which the shaping | molding die was filled, (b) is the state which pressure-reduced, (c) shows the state in which the pore was formed in the viscous composition. Is. It is a perspective view which shows the external appearance shape of the aluminum porous sintered compact after sintering in the said embodiment.

Hereinafter, an embodiment of a method for producing an aluminum porous sintered body according to the present invention will be described with reference to the drawings.
In this production method, a viscous composition containing bubbles is obtained by mixing an aluminum mixed raw material powder containing titanium powder and / or titanium hydride powder as a sintering aid with aluminum powder, water, and a water-soluble resin binder. The viscous composition preparation step, the pre-sintering step of obtaining the pre-sintered compact by freezing and drying the viscous composition, and the pre-sintered compact in the inert atmosphere or in vacuum When the temperature at which the aluminum mixed raw material powder starts melting is Tm (° C.), it is roughly constituted by a firing step of heating and firing at a temperature T (° C.) of Tm−10 (° C.) ≦ T ≦ 685 (° C.). It is a thing.

  First, as the aluminum powder used in this production method, one having an average particle diameter of 2 to 200 μm is used. This is because when the average particle size becomes small, a large amount of a water-soluble resin binder is added to the aluminum powder so that the viscous composition is viscous enough to be molded into a desired shape, and before sintering. It is necessary for the body to have handling strength. However, when a large amount of the water-soluble resin binder is added, the amount of carbon remaining in the aluminum is increased when the pre-sintered molded body is heated and fired, thereby inhibiting the sintering reaction. On the other hand, when the particle diameter of the aluminum powder is too large, the strength of the finally obtained aluminum porous sintered body is lowered. Therefore, as the aluminum powder, those having an average particle diameter in the range of 2 to 200 μm, more preferably in the range of 7 to 40 μm are used as described above.

Further, titanium and / or titanium hydride are mixed with the aluminum powder. This is because, in the subsequent baking step, the pre-sintered compact is heated and fired at Tm-10 (° C.) ≦ heating and firing temperature T ≦ 685 (° C.), thereby generating droplet masses. This is because there is no aluminum free sintering. Further, titanium hydride (TiH ₂ ) has a titanium content of 47.88 (molecular weight of titanium) / (47.88 + 1 (molecular weight of hydrogen) × 2) and is 95% by mass or more, and 470 to 530. Since it is dehydrogenated at titanium and becomes titanium, it is thermally decomposed by the above-mentioned heating and baking to become titanium. Accordingly, free sintering of aluminum is possible without generating droplet lumps even when titanium hydride is mixed.

  At that time, when the average particle diameter of titanium or titanium hydride is r (μm), the mixing ratio when the mixing ratio of titanium or titanium hydride is W mass% is 1 (μm). ≦ r ≦ 30 (μm), 0.1 (mass%) ≦ W ≦ 20 (mass%), and 0.1 ≦ W / r ≦ 2. That is, in the case of titanium hydride powder having an average particle diameter of 4 μm, the compounding ratio W is 0.4 ≦ 8% by mass because 0.1 ≦ W / 4 ≦ 2, and the titanium powder having an average particle diameter of 20 μm In this case, the compounding ratio W is 2 to 40% by mass because 0.1 ≦ W / 20 ≦ 2, but 2 to 20% by mass from 0.1 (% by mass) ≦ W ≦ 20 (% by mass). %.

  The average particle diameter of titanium hydride is 0.1 (μm) ≦ r ≦ 30 (μm), more preferably 4 (μm) ≦ r ≦ 20 (μm). If it is 1 μm or less, there is a risk of spontaneous ignition. On the other hand, if it exceeds 30 μm, the titanium hydride becomes titanium particles coated with a compound of aluminum and titanium after sintering. This is because the compound phase of aluminum and titanium is easily peeled off from the titanium particles, and desired strength is obtained in the sintered body.

  Further, 0.1 (mass%) ≦ W ≦ 20 (mass%) is set when the sintering aid powder is mixed in the aluminum mixed raw material powder when the blending ratio W of the sintering assistant powder exceeds 20 mass%. This makes it possible to have a contact, so that the reaction heat between aluminum and titanium cannot be controlled, and a desired porous sintered body cannot be obtained.

  Further, even within the range of 0.1 (mass%) ≦ W ≦ 20 (mass%), the reaction heat of aluminum and titanium may become too large depending on the particle size of the sintering aid powder, In some cases, the temperature of the aluminum melted by heat is further increased, the viscosity is lowered, and droplets are generated.

  Therefore, from the results of observing specimens prepared under various conditions with an electron microscope, the surface layer with a substantially constant thickness from the exposed surface side of the titanium particles within a range in which the calorific value can be controlled by the blending amount and particle size of titanium. It was found that only the part reacted with aluminum. Thus, it was experimentally derived that it is desirable that 1 (μm) ≦ r ≦ 30 (μm) and 0.1 ≦ W / r ≦ 2 in order to prevent the generation of droplets.

The reason why 0.1 ≦ W / r ≦ 2 is explained below. When titanium is used for the sintering aid powder, the average particle diameter of titanium is r, the number of titanium particles is N, and the added mass of titanium. Is W, the specific gravity of titanium is D, and the amount of decrease in the titanium particle size due to the reaction with aluminum is d, the reaction heat quantity Q is proportional to the volume of the reacted titanium, so that Q∝4πr ² dN. Furthermore, since the addition amount of the titanium particles is calculated by the product of the average volume of one titanium particle and the number of titanium particles, w = 4 / 3πr ³ DN. Therefore, when the latter equation is substituted into the former equation, Q∝3wd / rD is obtained. Here, from the observation result that 3 / D is a constant and d is almost constant regardless of the sintering condition, Q∝w / r. Therefore, by experimentally determining the W / r range in which no droplets are generated and limiting them as described above, the generation of droplets due to excessive reaction heat between aluminum and titanium can be prevented.

  Next, in the viscous composition preparation step, the aluminum mixed raw material powder is made of at least one of polyvinyl alcohol, methylcellulose and ethylcellulose as a water-soluble resin binder, and polyethylene glycol, glycerin and phthalic acid as a plasticizer. At least one of di-N-butyl is added, and distilled water and alkylbetaine as a surfactant are added.

  Thus, by using polyvinyl alcohol, methyl cellulose, or ethyl cellulose as the water-soluble resin binder, a relatively small amount is sufficient. For this reason, the addition amount is set within the range of 0.5% to 7% of the mass of the aluminum mixed raw material powder. If the content of the aluminum mixed raw material powder exceeds 7%, the amount of carbon remaining in the pre-sintered molded body during heating and firing is increased, and the sintering reaction is inhibited. It is because the handling intensity | strength of the molded object before sintering is not ensured that it is less than.

  In addition, 0.02% to 3% of the mass of the aluminum mixed raw material powder is added to the alkylbetaine. This is because by making 0.02% or more of the mass of the aluminum mixed raw material powder, bubbles are effectively generated when mixing the water-insoluble hydrocarbon organic solvent described later, and by making it 3% or less. Inhibition of the sintering reaction due to an increase in the amount of carbon remaining in the pre-sintered compact or the like is prevented.

  And in this viscous composition preparation process, the said material is vacuum-kneaded for 1 to 1.5 hours, and a viscous composition is created, removing gas, such as a bubble and dissolved gas contained inside. The viscous composition is then pre-cooled for about 1 hour at a temperature above the freezing point of the viscous composition at that pressure and below the boiling point, for example, 5 ° C. or below. Thereby, the viscosity of a viscous composition becomes higher than normal temperature.

Next, bubble nuclei are dispersed and formed in the viscous composition using the cell nucleus forming apparatus 1 shown in FIG.
In this apparatus 1, a supply pipe 3 for a viscous composition S and a supply pipe 4 for an additive gas G are connected to a lower part of one end of a stirring tank 2, and a discharge pipe 5 for the viscous composition S is connected to an upper part of the other end. In addition, a plurality of stirrers 6 are arranged in the inside from the one end to the other end, and the inside of the stirring tank 2 is maintained at the above-described preliminary cooling temperature.

Then, the additive composition G is introduced from the supply pipe 4 while continuously supplying the viscous composition S from the supply pipe 3 at one end into the stirring tank 2, and is stirred at a high speed by the stirrer 5 to the other end. By sending, the additive gas G is dispersed in the viscous composition S, and the bubble nucleus G ₁ is formed. At this time, since the inside of the agitation tank 2 is maintained at the precooling temperature, the additive gas G is prevented from being released from the viscous composition S whose viscosity is increased. As a result, almost the entire amount becomes the cell nucleus G ₁ and is dispersed in the viscous composition S.

Here, the additive gas G is preferably a gas that does not denature the viscous composition S and does not remain as an impurity after sintering, such as air, oxygen, nitrogen, argon, helium, carbon dioxide, and the like. The volume ratio of the additive gas G to the volume of the viscous composition S is adjusted to 10: 0.1 to 8 in consideration of the final porosity. Further, a stirrer 6 stirring speed by, stirring time in stirred tank 2, by setting the pressure inside the agitation tank 2 (0～1Atm gauge pressure) appropriate to control the average diameter of the bubble nuclei G ₁ it can.

Next, the viscous composition S containing the bubble nuclei G ₁ dispersed in the stirring tank 2 of the bubble nucleation apparatus 1 is discharged from the discharge pipe 5 while maintaining the precooling temperature, and is formed into a split mold 7 for molding. Fill. Specifically, as the split mold 7, for example, a 100W × 150L × 80H aluminum product is used, and after the silicone release agent is applied to the inner surface thereof, the viscous composition S is injected to a height of 10 mm. .

Then, as shown in FIG. 2 (a), the split mold 7 is placed in a decompression vessel (not shown), and the viscous composition S boils inside over a certain time (for example, 1 to 15 minutes). The pressure is reduced to 0.01 to 0.4 atm, which is higher than the pressure and lower than the atmospheric pressure. Then, since the viscous composition S is maintained at the preliminary cooling temperature, the bubble nucleus G ₁ gradually expands to become the bubble G ₂ without boiling, as shown in FIG. 3B. Along with this, the volume of the viscous composition S increases.

Finally, as shown in FIG. 3C, pores G ₃ in which adjacent bubbles G ₂ are continuous are formed in the viscous composition S. Therefore, after the viscous composition S is kept at the above temperature and pressure and allowed to stand for 1 to 60 minutes to stabilize, the freezing temperature (−80 ° C. or more and below the freezing point of the viscous composition S ( For example, it is cooled to −40 ° C. and held for 0.1 to 2 hours. Then, the water in the viscous composition S is solidified, so that the shape of the viscous composition S including the pores G ₃ is fixed.

  Next, the viscous composition S is placed in a vacuum atmosphere (for example, about 0.001 atm, 15 ° C.) to sublimate the moisture inside and dried, and then removed from the split mold 7. Thus, a thick plate-like pre-sintered compact having a size of 100 W × 150 L × 43 H in which the aluminum mixed raw material powder is held by the water-soluble resin binder is obtained.

  Then, next, the pre-sintered compact is placed on an alumina setter with zirconia bedding and pre-sintered by heating and holding at 520 ° C. for 1 hour in an argon atmosphere with a dew point of −20 ° C. Do. This removes the binder solution of the water-soluble resin binder component, plasticizer component, distilled water and alkylbetaine of the pre-sintered molded body, and when titanium hydride is used as the sintering aid powder. Is dehydrogenated.

Then, the pre-sintered shaped body after the temporary firing is heated and fired at Tm-10 (° C.) ≦ heating and firing temperature T ≦ 685 (° C.) to obtain an aluminum porous sintered body.
It is considered that the reaction between aluminum and titanium starts by heating the pre-sintered compact to the melting temperature Tm (° C.). Has a small amount of eutectic alloy elements such as Fe and Si as impurities in aluminum and its melting point is lowered. Therefore, it is considered that the reaction between aluminum and titanium starts by heating to Tm-10 (° C.). Because it is. Actually, while the melting point of aluminum is 660 ° C., the melting start temperature is around 650 ° C. for atomized powder having a purity of about 98% to 99.7% distributed as pure aluminum powder.

  On the other hand, the peritectic temperature of aluminum and titanium is 665 ° C., and further, when the latent heat of fusion is input, the sintered body of aluminum melts, so it is necessary to keep the furnace atmosphere temperature at 685 ° C. or lower.

  In addition, in order to suppress the growth of the oxide film of the aluminum particle surface and the titanium particle surface, it is necessary to perform the heat baking in the sintering process in a non-oxidizing atmosphere. However, if the heating temperature is kept at 400 ° C. or lower for about 30 minutes, the oxide film on the aluminum particle surface and the titanium particle surface does not grow so much even if heated in air. After debinding by heating and holding at 300 ° C. to 400 ° C. for about 10 minutes in air, it may be fired at a predetermined temperature in an argon atmosphere.

  As shown in FIG. 3, the aluminum porous sintered body 10 obtained by the above-mentioned sintering has a metal skeleton having a three-dimensional network structure made of a porous metal sintered body, and voids are formed between the metal skeletons. have. Further, the Al—Ti compound is dispersed in the perforated metal sintered body, and 20 or more pores are formed per 1 cm of the linear length, and the total porosity is 70 to 90%. Incidentally, the dimension of the obtained aluminum porous sintered body 10 is approximately 75 W × 110 L × 30 H.

  Therefore, it is suitable for heat transfer members such as heat sinks, heat pipes, various filters, catalyst carriers, lightweight structural members, silencer damping materials, heat insulating materials, electromagnetic wave shielding materials, etc. Thick plate shape, block shape, cylindrical shape or other It can be suitably used as a three-dimensional irregularly shaped porous metal plate material.

  Thick plate shape, block shape, cylindrical shape or other three-dimensional shapes suitable as heat transfer members such as heat sinks, heat pipes, various filters, catalyst carriers, lightweight structural members, silencer damping materials, heat insulating materials, electromagnetic wave shielding materials, etc. It can be used when producing a deformed aluminum porous sintered body.

10 Aluminum porous sintered body S Viscous composition G ₁ bubble nucleus G ₂ bubble G ₃ pores

Claims (6)

Viscosity composition preparation step for obtaining a viscous composition containing bubbles by mixing aluminum powder containing titanium powder and / or titanium hydride powder as a sintering aid with aluminum powder, water and a water-soluble resin binder When,
A pre-sintering step of obtaining a pre-sintered compact by filling this viscous composition into a container having a predetermined shape, and freezing and drying;
Tm−10 (° C.) ≦ T ≦ 685 (° C.), where Tm (° C.) is the temperature at which the aluminum mixed raw material powder starts melting in an inert atmosphere or vacuum. it was closed and the firing step of firing at a temperature T (° C.) of)
When the average particle diameter of the sintering aid powder is r (μm) and the blending ratio of the sintering aid powder is W mass%, 1 (μm) ≦ r ≦ 30 (μm), 1 ≦ W ≦ 20 (% by mass), and method for producing a porous sintered aluminum to 0.1 ≦ W / r ≦ 2 der wherein Rukoto.   In the pre-sintering step, the pressure is reduced to a pressure higher than the pressure at which the viscous composition boils and lower than the atmospheric pressure, the mixed bubbles are enlarged, and the viscous composition is reduced in the reduced pressure state. The method for producing an aluminum porous sintered body according to claim 1, wherein the product is frozen.   The pre-baking step includes performing the freezing of the viscous composition after holding the viscous composition at a temperature of 0.1 ° C. or higher and 10 ° C. or lower than the freezing temperature for 1 to 60 minutes. The method for producing a porous aluminum sintered body according to claim 1 or 2, characterized in that:   The method for producing a porous aluminum sintered body according to any one of claims 1 to 3, wherein the aluminum powder has an average particle diameter of 2 to 200 µm. The aluminum porous material according to any one of claims 1 to 4, wherein the water-soluble resin binder is contained within a range of 0.1% to 7% of a mass of the aluminum mixed raw material powder. A method for producing a sintered body. The porous aluminum according to any one of claims 1 to 5, wherein in the viscous composition preparation step, a surfactant within a range of 0.02 to 3% of the mass of the aluminum mixed raw material powder is added. Of manufacturing a sintered material.

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