Method of manufacturing foam metal made of aggregate of single foam

Abstract

To provide a method of manufacturing a foam metal formed of an aggregate of single foams and satisfying the following conditions that a foam metal is manufactured without melting a metal, a foaming agent is not used, the foaming metal is light, an aggregate of fine particles covers a surface layer of balloons filled with gas near atmospheric pressure, a shape of the component, a sheet, and a container made of the foam metal can be changed freely, and a material of the metal constituting a single foam body is not limited.SOLUTION: An aggregate of balloons 1 whose surface is covered with a suspension of an aggregate of metal compound crystals dispersed in an organic compound whose boiling point is higher than the temperature at which the metal compound starts to thermally decompose and lower than the temperature at which the metal compound completes thermal decomposition is used as a raw material, the raw material is heat-treated to thermally decompose the metal compound, the surface of the balloons is covered with the aggregate 2 of the metal fine particles, and the adjacent metal fine particles are metal-bonded to join the balloons together to form a metal foam consisting of an aggregate of balloons joined by the aggregate of metal bonded metal fine particles.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a metal foam consisting of a collection of single bubbles, in which the surface of a balloon consisting of a vaporized organic compound is covered with a collection of metallic fine particles that are metallically bonded to form single bubbles, and adjacent metal fine particles covering the surface of the balloon are metallically bonded to each other to bond the single bubbles together. Prior to the present invention, the inventor had registered a patent (Japanese Patent No. 6228782) for the production of a foam metal comprising an aggregate of void shells in which a collection of granular particles of two types of metals forms void shells, and the void shells are joined together by metallic bonds between the granular particles of the second metal. In contrast, the present invention relates to a method for producing a metal foam consisting of a collection of single bubbles, in which the surface of a balloon made of a vaporized organic compound is covered with a collection of metallic fine particles that are metallically bonded to form single bubbles, and adjacent metal fine particles covering the surface of the balloon are metallically bonded to each other to join the single bubbles together. Metal foam is a cellular structure of metal, in which the bubbles are independent of each other and are called closed-cell foams, and in which the bubbles are connected to each other and are called open-cell foams, respectively. In addition, open-cell foams are sometimes referred to as open-cell structures, and closed-cell foams are sometimes referred to as closed-cell structures, but in the present invention, the cellular structure in which the bubbles are independent of each other is referred to as closed-cell foams. [Background technology]

[0002] In metal foams, the volume occupied by the voids (also called cells or pores) is larger than the volume occupied by the metal, and it is lighter than metals with a dense structure made of conventional melt-cast materials. Therefore, metal foams are lighter than magnesium alloys, which are the lightest practical metals, and can achieve weight reduction that exceeds the limits of weight reduction using melt-cast materials. For example, the use of metal foams can achieve ultra-lightweight products that exceed the use of aluminum in automobiles and magnesium in electrical products. In addition, since metal foams are porous and have a large specific surface area, they have the potential to be functional materials with high energy absorption capacity, heat exchange capacity, insulation properties, vibration damping properties, and sound absorption properties. They can also be applied to catalyst carriers and electrodes, and if they can be combined with other foams and substrates or other parts, they can be applied to a wide range of parts. In this way, metal foams are a material that is in the process of developing new application fields with various possibilities.

[0003] There are various methods for producing metal foam, such as the casting method (also called the foaming melting method or melt thickening method) in which metal foam is produced by casting, and the precursor method in which a foaming agent is mixed with powdered metal such as an aluminum alloy to produce a precursor (also called a preform or metal foam precursor), which is then heated to foam. In addition, there are various methods proposed, such as the gas expansion method, in which argon gas is injected into metal powder, and the gas expands during pressure sintering to form pores and sinter the metal powder, and the continuous zone melting method, in which nitrogen is absorbed into molten metal, which is then poured into a cooled mold and solidified in one direction. The casting method is, for example, a method in which calcium or the like is added to a molten metal of pure aluminum as a base material to thicken it, and a foaming agent such as titanium dihydride is added to cause foaming (see, for example, Patent Document 1). In the precursor method, after preparing a precursor, the precursor is heated to decompose the foaming agent to generate gas, and the base material softened by the generation of gas is expanded. Various methods have been proposed as specific methods of the precursor method, for example, powder metallurgy and roll bonding. In the powder metallurgy method, for example, a powder of a base material such as an aluminum alloy and a powder of a foaming agent are mixed until they become uniform, and the mixture is extrusion molded. Thereafter, the foaming agent is foamed by heating in an infrared furnace or the like (for example, see Patent Documents 2 and 3). In the roll bonding method, a plurality of base plate materials are prepared, and the plates are surface-treated as necessary, and then a foaming agent is sandwiched between the plates and rolled to bond the plurality of plates. This rolling process is repeated to uniformly disperse the foaming agent in the base material, resulting in a foam metal precursor (see, for example, Patent Document 4).

[0004] However, in the manufacturing method using a foaming agent such as titanium dihydride, the material of the foam metal that can be manufactured is limited by the thermal decomposition temperature of the foaming agent. For example, the thermal decomposition temperature of titanium dihydride TiH2 is 470°C, so the more the melting point of the metal is far from 470°C, the more the pores of the hydrogen gas generated by the thermal decomposition of titanium dihydride expand, and the pores combine with each other and disappear, so when titanium dihydride is used, it is limited to aluminum with a melting point of 660°C and some aluminum alloys with low melting points. On the other hand, since titanium dihydride is an expensive inorganic compound, a cheaper foaming agent, calcium carbonate CaCO3, may be used, but since the thermal decomposition temperature of calcium carbonate is 825°C, the foam metal is limited to metals with a melting point lower than 1000°C. In this way, in the casting method and precursor method using a foaming agent, the foam metal that can be manufactured at the thermal decomposition temperature of the foaming agent is limited. In addition, in the casting method, it is difficult to uniformly disperse the foaming agent in the molten metal, so it is difficult to control the size and distribution of the bubbles, etc. As a result, the bubbles become larger than necessary, and the required strength cannot be obtained, which limits the uses of the foam metal. Furthermore, while powder metallurgy has the advantage of making it easier to control the shape of the bubbles, the raw material powder of the base material is more expensive than sheet material, and the process of producing the precursor is complicated and time-consuming, resulting in low productivity and expensive foam metal. In addition, the roll bonding method requires pretreatment such as annealing and surface treatment of the bonding surface because the plates are bonded by rolling, and also consumes a lot of energy because heat treatment is performed before and after rolling, and further requires multiple rolling cycles to uniformly disperse the foaming agent, and the rolled material needs to be cut after each rolling cycle, which further reduces the productivity of the foamed metal and increases the production cost of the foamed metal. As explained above, metal foam is a material that is still in the process of development and has many possibilities. However, various problems arising from the manufacturing principles are obstacles to the development of new fields. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2007-61865 A [Patent Document 2] DE 1048360 A1 [Patent Document 3] DE 4101630 A1 [Patent Document 4] JP 2004-285446 A Summary of the Invention [Problem to be solved by the invention]

[0006] Here, the fundamental problems associated with the above-mentioned conventional methods for producing metal foam and the requirements for a new method that does not have these fundamental problems will be summarized. First, the conventional technology heats the metal to a temperature where it melts. However, the high melting point of the metal and the high heat treatment temperature bring about various problems and restrictions. Therefore, the first requirement for the new manufacturing method is that it can produce foam metal without melting the metal. Therefore, the new manufacturing method has a completely different structure of the metal that constitutes the single foam from the conventional method. Secondly, in the conventional technology, bubbles are formed by the thermal decomposition of the foaming agent. This limits the type of foam metal that can be produced at the thermal decomposition temperature of the foaming agent, and also causes problems with the size and distribution of the bubbles. Therefore, the second requirement for the new manufacturing method is to form pores with a new substance without using a foaming agent. Third, conventional techniques produce foam metals using complicated and disconnected manufacturing processes, such as the precursor process, powder metallurgy process, and roll bonding process. This results in high manufacturing costs and limits the applications of foam metals. Therefore, the third requirement for a new manufacturing method is that it can produce inexpensive foam metals using a process that involves a series of simple processes. Fourth, if the individual cells are so light that they have almost no weight, the metal foam consisting of an aggregate of individual cells will be lighter than conventional metal foams, expanding the range of uses for the metal foam. Therefore, the fourth requirement for the new manufacturing method is that the weight of the resulting metal foam be lighter than conventional metal foams. Fifth, if the surface of a balloon filled with gas close to atmospheric pressure can be covered with a collection of fine particles to form individual bubbles, and if the individual bubbles can be formed to be about 1 micron in size, the individual bubbles will have a certain level of mechanical strength, and furthermore, a metal foam consisting of a huge number of individual bubbles will have increased mechanical strength compared to conventional metal foams, expanding the range of uses for metal foams. Therefore, the fifth requirement for the new manufacturing method is that the surface of a balloon filled with gas close to atmospheric pressure can be covered with a collection of fine particles to form individual bubbles that are about 1 micron in size. Sixth, if the shape of the part made of metal foam can be freely changed, the width of the sheet made of metal foam can be freely changed, and further, the shape and thickness of the container or part made of metal foam can be freely changed, the applications of metal foam can be greatly expanded. Therefore, the sixth requirement for the new manufacturing method is that the shape of the part made of metal foam can be freely changed, the width of the sheet made of metal foam can be freely changed, and further, the shape and thickness of the container or part made of metal foam can be freely changed. Seventh, if it were possible to produce independent foam bodies from various metals regardless of the melting point of the metal, the applications of metal foams would be expanded. Therefore, the seventh requirement for the new manufacturing method is that there be no restrictions on the metal material that constitutes the independent foam bodies. The problem to be solved by the present invention is to find a completely new method for producing metal foam that satisfies the seven requirements mentioned above. Because the manufacturing principle is different from that of conventional manufacturing methods, it does not have any of the fundamental problems of conventional techniques. This will dramatically expand the properties of metal foam and the fields in which it can be applied. [Means for solving the problem]

[0007] The method for producing a raw material used in producing a metal foam consisting of an aggregate of single cells, in which aggregates of metal fine particles bonded together by metal bonding cover the surface of single cells and the aggregates of metal fine particles bonded together by metal bonding cover the surface and bond the single cells together, comprises the steps of: a first organic compound having a first property of a melting point higher than 30°C, a second property of a boiling point lower than the temperature at which thermal decomposition of a metal compound that precipitates a metal by thermal decomposition begins, and a third property of the crystals not dissolving or dispersing in a methanol solution of a second organic compound is dissolved in methanol to prepare a methanol solution of the first organic compound, the methanol solution of the first organic compound is then filled into a container in a vacuum bell jar, the vacuum bell jar is sealed and a vacuum pump is operated to reduce the pressure in the vacuum bell jar to a pressure lower than the saturated vapor pressure of the methanol, methanol is vaporized from the methanol solution of the first organic compound, a collection of crystals of the first organic compound is precipitated in the container in the vacuum bell jar, the vacuum bell jar is opened to atmospheric pressure, and the collection of crystals of the first organic compound is taken out from the container in the vacuum bell jar; Furthermore, the collection of crystals of the first organic compound is filled into a new container, and a plate material covering the entire surface of the collection of crystals of the first organic compound is placed on the collection of crystals of the first organic compound. After this, a compressive load is applied to the entire surface of the plate material to crush the crystals of the first organic compound in the new container. Furthermore, impact accelerations are repeatedly applied to the sides and bottom of the new container in three directions, front-back, left-right, and up-down, to rearrange the crushed collection of crystals of the first organic compound in the new container. After this, the compressive load is applied again to the entire surface of the plate material, and the crushed collection of crystals of the first organic compound is rearranged in the new container. The crushing of the crystals of the first organic compound is further continued, and the impact acceleration in the three directions is again repeatedly applied to the side and bottom of the new container. The pair of processes consisting of the process of applying the compressive load and the process of applying the impact acceleration are repeated, and when the plate stops moving when the compressive load is applied to the plate, it is determined that the crushing of the crystals of the first organic compound is complete, and the pair of processes are stopped, and the crystals are crushed into crystals of about 20 nm in size, which is close to 1 / 5 of the size of the crystals precipitated in the container, and then the plate is removed from the new container. Then, a metal compound having both a first property of being dispersed in methanol in a molecular state but not being dissolved in methanol and a second property of precipitating a metal by thermal decomposition is dispersed in methanol to prepare a methanol dispersion of the metal compound, and then the methanol dispersion of the metal compound is heated to the boiling point of the methanol to vaporize the methanol from the methanol dispersion of the metal compound, thereby precipitating a crystal cluster of the metal compound. Further, a second organic compound having a first property of a melting point lower than 10°C, a second property of a boiling point higher than the temperature at which the metal compound starts to thermally decompose and lower than the temperature at which the metal compound completes its thermal decomposition, a third property of a viscosity of 35 mPa·sec or more at 20°C, a fourth property that crystals of the first organic compound do not disperse or dissolve in a methanol solution obtained by dissolving the first organic compound in methanol, and a fifth property that crystals of the metal compound do not disperse or dissolve in the methanol solution obtained by dissolving the first organic compound in methanol, the entire surface of all balloons formed when a collection of crushed crystals of the first organic compound is vaporized. a weight of the second organic compound mass that is greater than the weight that can be covered by the mass of the second organic compound is weighed out, and the weighed mass of the second organic compound is mixed with methanol in an amount that is four times the weight of the mass of the second organic compound mass to prepare a methanol solution of the second organic compound; thereafter, a mass of the crystals of the metal compound having a weight less than the weighed mass of the second organic compound mass is mixed with the methanol solution of the second organic compound to prepare a first suspension in which the mass of the crystals of the metal compound is dispersed in the methanol solution of the second organic compound; Further, a mass of crushed crystals of the first organic compound is mixed with the mass of the first suspension to prepare a second suspension in which the mass of crushed crystals of the first organic compound is dispersed in the first suspension. Thereafter, the second suspension is filled into a new container in the vacuum bell jar, the vacuum bell jar is sealed, and a vacuum pump is operated to reduce the pressure in the vacuum bell jar to a pressure lower than the saturated vapor pressure of the first organic compound. As a result, first, methanol is evaporated from the methanol solution of the second organic compound, the first suspension becomes a third suspension in which a cluster of crystals of the metal compound is dispersed in a cluster of the second organic compound, and the third suspension covers the crushed crystals of the first organic compound, the crushed crystals of the first organic compound are then evaporated, balloons made of the gas of the first organic compound are formed, the surfaces of the balloons are covered with the third suspension and the balloons are bonded together via the third suspension, a cluster of balloons whose surfaces are covered with the third suspension are formed in a new container in the vacuum bell jar, and then the vacuum bell jar is opened to atmospheric pressure, and the cluster of balloons whose surfaces are covered with the third suspension is taken out from the vacuum bell jar. A method for producing a raw material used in producing a foam metal consisting of a collection of individual bubbles, comprising using the collection of balloons whose surfaces are covered with the third suspension as a raw material in producing a foam metal consisting of a collection of individual bubbles.

[0008] In other words, the raw materials used to manufacture metal foam are produced by carrying out the following six processes in succession. The method of each process, the phenomena that occur during the process, and the effects of the process will be explained in the order of the processes. First, a first organic compound having a melting point higher than 30°C and a boiling point lower than the temperature at which thermal decomposition of a metal compound that precipitates a metal by thermal decomposition begins is dissolved in methanol, and then the methanol solution of the first organic compound is filled into a container in a vacuum bell jar. The vacuum bell jar is then sealed and a vacuum pump is operated to reduce the pressure inside the vacuum bell jar to a pressure lower than the saturated vapor pressure of methanol, causing the methanol to vaporize from the methanol solution of the first organic compound, and causing a collection of crystals of the first organic compound to precipitate in the container in the vacuum bell jar. In other words, since the first organic compound constitutes a single-cell bubble balloon, if the first organic compound is solid at room temperature, a raw material that will become an aggregate of metal particles can be attached to the surface of the crystal of the first organic compound. Therefore, the melting point of the first organic compound is higher than 30°C. Furthermore, if a raw material that will become an aggregate of metal particles is attached to the surface of the crystal of the first organic compound and the crystal of the first organic compound is vaporized, a single-cell bubble balloon covered with the raw material that will become an aggregate of metal particles can be formed. Therefore, the boiling point of the first organic compound is lower than the temperature at which the thermal decomposition of the metal compound that precipitates metal by thermal decomposition begins, and the first organic compound can be easily vaporized. On the other hand, in order to attach a raw material that will become a cluster of metal particles to the surface of the crystals of the first organic compound, it is necessary to precipitate a cluster of crystals of the first organic compound. For this purpose, the first organic compound is dissolved in methanol, the methanol solution of the first organic compound is filled into a container in a vacuum bell jar, the vacuum bell jar is sealed, a vacuum pump is operated, the pressure in the vacuum bell jar is reduced to a pressure lower than the saturated vapor pressure of methanol, and methanol is vaporized from the methanol solution of the first organic compound, and a cluster of crystals of the first organic compound is precipitated in the container in the vacuum bell jar. On the other hand, if the melting point of the first organic compound is higher than the boiling point of methanol (65°C), the dissolved first organic compound is precipitated when the methanol solution of the first organic compound is heated to the boiling point of methanol and the methanol is vaporized. However, the boiling points of all the first organic compounds are not higher than 65°C. For this purpose, a container in a vacuum bell jar was filled with a solution of the first organic compound in methanol, and the pressure in the vacuum bell jar was reduced to a pressure lower than the saturated vapor pressure of methanol, causing the methanol to evaporate from the solution of the first organic compound in methanol, and precipitating a collection of crystals of the first organic compound having a melting point higher than 30°C. These crystals are a collection of crystals formed by the accumulation of crystals formed by single molecules of the first organic compound, since the first organic compound dissolved in methanol in a molecular state precipitated as crystals. Therefore, when stress is applied to the crystals, the crystals are broken down into fine crystals. On the other hand, the finer the crystals, the more difficult it is to apply stress to the crystals, and there is a limit to how fine the crystals can be made. Secondly, the crystals of the first organic compound are crushed to about 1 / 5 of their original size. In other words, if a raw material that will become a collection of metal fine particles is attached to the surface of the crystals of the first organic compound and the crystals of the first organic compound are vaporized, a balloon covered with the raw material that will become a collection of metal fine particles can be formed. On the other hand, when the crystals of the first organic compound are vaporized, they become a gas of the first organic compound with a volume obtained by multiplying the molar ratio of the crystals of the first organic compound by 22.4 liters. Therefore, the larger the molar ratio of the crystals of the first organic compound, that is, the larger the crystals of the first organic compound, the larger the volume of the gas of the first organic compound. For example, the volume of the vaporized crystals of the first organic compound with a diameter of 100 nm is 125 times the volume of the vaporized crystals of the first organic compound with a diameter of 20 nm. In addition, assuming that the specific gravity of the first organic compound is 1, the molar mass of the first organic compound is 86 g, and the crystal of the first organic compound is a sphere, when a spherical crystal of the first organic compound with a diameter of 20 nm is vaporized, it becomes a spherical balloon with a radius of 645 nm. Therefore, when a crystal of the first organic compound with a diameter of 100 nm is vaporized, it becomes difficult to cover the balloon made of the gas of the first organic compound with a raw material that becomes a collection of metal fine particles. For this reason, the crystal of the first organic compound was crushed to about 1 / 5 of its original size by the following process. First, a container is filled with a collection of crystals of the first organic compound, a plate material is placed over the collection of crystals of the first organic compound in the container, the collection of crystals of the first organic compound is constrained within the container, and the collection of crystals of the first organic compound is compressed through the plate material. At this time, the larger the crystal size, the easier it is to break. For this reason, the relatively larger crystals are broken first, and the crystals continue to break while the compressive load is applied. Meanwhile, in the collection of crystals in the container, new voids are formed by the breakage of the crystals, and while the compressive load is applied, the crystals move to fill the voids. After this, the applied compressive load is stopped, and impact acceleration is repeatedly applied to the container in three directions, front-back, left-right, and up-down. At this time, the crystals do not scatter because they are constrained within the container by the plate material, and the crystals move to fill the voids, and the crushed collection of crystals is rearranged within the container. Furthermore, after the applied impact acceleration is stopped, a compressive load is again applied to the collection of crushed crystals through the plate material. At this time, the crushing of the crushed crystals proceeds against the cluster of finer crystals. After this, the container is again repeatedly subjected to impact acceleration in three directions to further rearrange the cluster of finer crystals. A pair of processes consisting of the process of applying a compressive load and the process of applying an impact acceleration in three directions is repeated. On the other hand, the finer the crystals are, the more difficult it becomes to apply compressive stress to the crystals even when a compressive load is applied, and there is a limit to how fine the crystals can be. When the limit of how fine the crystals can be made is reached, the crushing of the crystals does not proceed even when a compressive load is applied to the plate material, and no movement is observed in the plate material to which the compressive load is applied. At this point, the pair of processes is stopped. As a result, the size of the crystals becomes approximately 20 nm, which is close to 1 / 5 of the size at the time of precipitation. In addition, the crushed crystals of the first organic compound are vaporized to form a fine balloon, so the weight of the cluster of crushed crystals of the first organic compound is small. For this reason, the compressive load applied to the plate material is a compressive load equivalent to 3-5 kg ​​weight depending on the size of the container. In addition, the impact acceleration applied to the container is 0.2-0.3G depending on the size of the container. Thirdly, a collection of crystals of the metal compound is precipitated. For this purpose, the metal compound is dispersed in methanol, and then the temperature of the methanol dispersion of the metal compound is raised to the boiling point of methanol, the methanol is evaporated, and a collection of crystals of the metal compound is precipitated. That is, when a metal compound that precipitates a metal by thermal decomposition is dispersed in methanol, which is the most commonly used organic solvent, the metal compound becomes a molecular state and disperses in the methanol. In contrast, when a metal compound dissolves in methanol, the metal constituting the metal compound becomes a metal ion and dissolves in the methanol, and the dissolved metal compound cannot return to the metal compound before dissolution. For this reason, even if methanol is evaporated from a methanol solution of the metal compound, crystals of the metal compound before dissolution are not precipitated. Therefore, a metal compound that does not dissolve in methanol but disperses is used as a metal compound that precipitates a metal by thermal decomposition. As a result, when methanol is evaporated from a methanol dispersion of the metal compound, the metal compound precipitates as crystals of the metal compound smaller than 100 nm. These crystals are a collection of crystals formed by the accumulation of single molecules of metal compounds, which are metal compounds dispersed in the methanol in a molecular state and precipitated as crystals. The evaporated methanol is recovered and reused. Fourth, the second organic compound cluster is dissolved in methanol to prepare a first suspension in which a cluster of crystals of a metal compound is dispersed in the methanol solution. This suspension is a raw material that becomes a cluster of metal fine particles that adhere to the surface of the crushed crystals of the first organic compound. That is, the second organic compound constituting the first suspension has five properties: a melting point lower than 10°C, a boiling point higher than the temperature at which the thermal decomposition of the metal compound starts and lower than the temperature at which the thermal decomposition of the metal compound is completed, a viscosity of 35 mPa·sec or more at 20°C, the crystals of the first organic compound do not disperse or dissolve in the methanol solution in which the second organic compound is dissolved in methanol, and the crystals of the metal compound do not disperse or dissolve. That is, in the sixth process, the second suspension in which a cluster of crushed crystals of the first organic compound is dispersed in the first suspension is filled in a container in a vacuum bell jar, the vacuum pump is operated, the pressure in the vacuum bell jar is reduced to a pressure lower than the saturated vapor pressure of the first organic compound, methanol is evaporated from the first suspension, the first suspension is converted into a third suspension in which a cluster of crystals of a metal compound is dispersed in the second organic compound, the crushed crystals of the first organic compound are evaporated to form a balloon of the gas of the first organic compound, and the balloon is covered with the third suspension in which methanol is evaporated from the first suspension. The second organic compound is an organic compound having a melting point lower than 10°C and being liquid at room temperature. In addition, since the boiling point of the second organic compound is higher than the boiling point of the first organic compound, the second organic compound remains in the third suspension when the crystals of the first organic compound are evaporated. In addition, before the crushed crystals of the first organic compound are vaporized to form a balloon made of the gas of the first organic compound, methanol vaporizes from the first suspension that covered the surface of the crushed crystals of the first organic compound, and a third suspension in which a collection of crystals of a metal compound is dispersed in the second organic compound covers the surface of the balloon. For this reason, the viscosity of the second organic compound is high at 35 mPa·sec or more at 20°C. As a result, when the crushed crystals of the first organic compound are vaporized to form a balloon made of the gas of the first organic compound, the third suspension that covered the surface of the crushed crystals of the first organic compound is greatly deformed, but since the viscosity of the third suspension is high and it covered the surface of the crushed crystals of the first organic compound with a certain thickness, the third suspension deforms and covers the balloon. In addition, the balloons are bonded to each other via the third suspension that covers the surface of the balloon. As a result, a collection of balloons covered with the third suspension that are bonded to each other via the third suspension are created. Furthermore, since the first suspension is composed of a methanol dilution of the second organic compound and a collection of crystals of the metal compound, the crystals of the metal compound do not disperse or dissolve in the second organic compound. When the first organic compound, which is only about 20 nm in size, vaporizes, the gas of the first organic compound occupies the volume of a sphere with a radius of about 650 nm.Therefore, in order to cover the entire surface of all the balloons from which the crushed crystals of the first organic compound have evaporated with the third suspension, the weights of both the second organic compound and the metal compound are nearly six orders of magnitude greater than the weight of the first organic compound. Next, the procedure for preparing the first suspension will be described. First, the second organic compound is weighed out to a weight greater than the weight that can cover the surface of all the balloons formed when the crushed crystal clusters of the first organic compound are vaporized. This allows the surface of the balloon to be covered with a third suspension of a certain thickness. Next, the weighed second organic compound cluster is mixed with methanol of a weight four times greater than the weight of the second organic compound cluster to prepare a methanol solution of the second organic compound. After this, a crystal cluster of a metal compound of a weight less than the weighed weight of the second organic compound cluster is mixed with the methanol solution of the second organic compound to prepare a first suspension in which the crystal clusters of the metal compound are dispersed in the methanol solution of the second organic compound. Fifth, a mass of crushed crystals of the first organic compound is mixed into the mass of the first suspension to prepare a second suspension in which the mass of crushed crystals of the first organic compound is dispersed in the first suspension. The mass of crushed crystals of the first organic compound is neither dissolved nor dispersed in the methanol solution of the second organic compound. That is, in the sixth process, the crystals of the first organic compound are vaporized to form a balloon made of the gas of the first organic compound, and the surface of all the balloons is covered with the third suspension in which methanol is vaporized from the first suspension, so that the weight of the mass of crushed crystals of the first organic compound constituting the second suspension is significantly less than the weight of the second organic compound constituting the first suspension. As a result, the crystals of the first organic compound are vaporized, and the surface of the balloon having a volume equal to the molar ratio of the crystals of the first organic compound multiplied by 22.4 liters can be covered with the third suspension. Sixth, the second suspension is filled into a container in a vacuum bell jar, a vacuum pump is operated, and the pressure in the vacuum bell jar is reduced to a pressure lower than the saturated vapor pressure of the first organic compound, methanol is evaporated from the methanol solution of the second organic compound, and then the cluster of crushed crystals of the first organic compound is evaporated. That is, when methanol is evaporated from the methanol solution of the second organic compound, the first suspension becomes a third suspension in which clusters of crystals of a metal compound are dispersed in the second organic compound, and the third suspension covers the crushed crystals of the first organic compound to a certain thickness. Next, the crushed crystals of the first organic compound are evaporated, and a balloon made of the gas of the first organic compound is formed in an equilibrium state, and the third suspension covers the surface of the equilibrium balloon, and a cluster of balloons whose surfaces are covered with the third suspension is formed in the container in the vacuum bell jar. In addition, the balloons are bonded to each other via the third suspension covering the surface of the balloons. That is, when the crushed crystals of the first organic compound evaporate to form a balloon made of the gas of the first organic compound, the third suspension covering the surface of the crushed crystals of the first organic compound is significantly deformed, but the viscosity of the third suspension is high at 35 mPa·sec or more at 20°C, and the third suspension covers the surface of the balloon because it covers the crushed crystals of the first organic compound with a certain thickness. The balloon covered with the third suspension is an irreversible change, so the balloon does not return to the crystals of the first organic compound. When the crushed first organic compound, which is about 20 nm in size, evaporates, a balloon with a radius of about 650 nm is formed. The evaporated methanol is recovered and reused. All six of the processes described above are simple. In addition, the raw materials used, such as methanol, organic compounds, and metal compounds, are general-purpose industrial chemicals. Therefore, by using inexpensive raw materials and carrying out the six simple processes in succession, the raw materials used in manufacturing metal foam can be produced inexpensively.

[0009] A method for producing a part made of foamed metal on a bottom surface of a container in the shape of said bottom surface by using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method described in paragraph 7, comprising the steps of: a container having a bottom shape corresponding to the shape of the part made of foamed metal to be manufactured is filled with a part of the collection of balloons having a surface covered with the third suspension manufactured by the method described in paragraph 7, the container is moved to a heat treatment device, the container is exposed to an atmosphere in which the metal compound constituting the third suspension is thermally decomposed, and the temperature is raised to a temperature at which the thermal decomposition of the metal compound is completed; As a result, the container is heated, and first, thermal decomposition of the metal compound that constitutes the third suspension begins, and the metal compound decomposes into organic molecules and metal molecules, the organic molecules and the metal molecules mix with the second organic compound, and this mixed mixture covers the surface of the balloon, and as the container is heated further, the second organic compound vaporizes, and a collection of the organic molecules and a collection of the metal molecules cover the surface of the balloon, and as the container is heated further, vaporization accompanied by the heat of vaporization of the organic molecules begins, and the surface of the balloon is gradually covered with a collection of the metal molecules, and as the container is heated further, When the evaporation of the organic molecules is complete, the metal molecules covering the surface of the balloon gather together to form metal microparticles, the collection of metal microparticles precipitates all at once on the surface of the balloon, the collection of metal microparticles stacks and metal bonds are formed at the sites where adjacent metal microparticles come into contact with each other, the collection of metal microparticles that have been metal-bonded stacks and covers the surface of the balloon, and adjacent metal microparticles covering the surface of the balloon are metal-bonded to each other, thereby bonding the balloons together via the collection of metal microparticles that have been metal-bonded, and a part consisting of a collection of balloons bonded by the collection of metal microparticles that have been metal-bonded is formed on the bottom surface of the container in the shape of the bottom surface. A method for producing a part made of foamed metal on a bottom surface of a container in the shape of said bottom surface, using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method described in paragraph 7.

[0010] In other words, a portion of the collection of balloons covered with the third suspension is filled into a container having the shape of the bottom surface of the container that corresponds to the shape of the part made of foamed metal to be manufactured, the container is exposed to an atmosphere in which the metal compound that constitutes the third suspension undergoes thermal decomposition, and the temperature is then raised to a temperature at which the thermal decomposition of the metal compound is completed, and a part made of foamed metal is manufactured into the bottom surface of the container in the shape of the bottom surface. That is, when the container is heated, the group of balloons covered with the third suspension is heated, and the following phenomenon occurs in the group of balloons covered with the third suspension in a time series. That is, the boiling point of the second organic compound is higher than the temperature at which the metal compound starts to thermally decompose, and lower than the temperature at which the metal compound completes its thermal decomposition. Therefore, when the thermal decomposition of the metal compound starts, the metal compound decomposes into organic molecules and metal molecules, and the organic molecules and metal molecules are mixed in the second organic compound, and the mixed mixture covers the surface of the balloon. After this, the second organic compound vaporizes, and the group of organic molecules and the group of metal molecules cover the surface of the balloon. Furthermore, when the organic molecules take the heat of vaporization and vaporization begins, the surface of the balloon is gradually covered with the group of metal molecules. Furthermore, when the vaporization of the organic molecules is completed, the metal molecules gather to form metal fine particles, and a group of metal fine particles with a size of about 50 nm precipitates all at once on the surface of the balloon, and the group of metal fine particles is layered. The clusters of metal particles are metallically bonded at the sites where adjacent metal particles come into contact with each other. Furthermore, adjacent metal particles covering the surface of the balloon are metallically bonded to each other, so that the balloons are joined together via the clusters of metallically bonded metal particles, and a part consisting of the cluster of balloons is formed on the bottom surface of the container in the shape of the bottom surface. The vaporized second organic compound is recovered and reused. Here, it is assumed that a collection of metal fine particles having a size of about 50 nm and bonded with metal is laminated in about 7 layers to cover the surface of the balloon. In addition, the laminated collection of metal fine particles is metal-bonded with 6 adjacent metal fine particles in the same layer, and with 5-6 adjacent metal fine particles in the upper and lower layers. Therefore, the collection of metal fine particles laminated with metal-bonded metal fine particles has airtightness against the gas that forms the balloon, and the gas of the balloon is kept inside the balloon. As a result, the balloon covered with the collection of metal fine particles bonded with metal, that is, the single bubble, has a size of about 1 micron. That is, when the crushed first organic compound having a size of about 20 nm is vaporized, a balloon with a radius of about 650 nm is formed. In addition, if a collection of metal fine particles having a size of about 50 nm is laminated in 7 layers on the surface of the balloon, the thickness of the collection of metal fine particles will be about 350 nm. On the other hand, if the interior of a metal sphere with a radius of 1000 nm is hollow and occupies 65% of the volume, the weight of the metal sphere will be reduced by nearly 65%. Therefore, if a single bubble is formed by laminating seven layers of metal particles with a size of about 50 nm on the surface of a balloon with a radius of about 650 nm, the weight of the metal sphere with a radius of 1000 nm will be reduced by 65%. Therefore, the weight reduction effect of a metal foam consisting of a collection of single bubbles is significant. The part made of the foam metal produced by the method described above provides the following effects. First, since the part made of foamed metal is formed on the bottom surface of the container as the shape of the bottom surface, there are no restrictions on the shape of the part made of foamed metal. Secondly, because the temperature at which the thermal decomposition of the metal compound is completed is 290°C, the temperature at which the metal particles precipitate is significantly lower than the melting point of the metal, and parts made of metal foam can be manufactured at a significantly lower temperature than parts made of conventional metal foam. Therefore, parts made of metal foam can be manufactured more cheaply than parts made of conventional metal foam. Thirdly, since the balloons are formed by vaporizing the powder of an organic compound, there are no restrictions on the use of foaming agents as in the conventional production of foamed metals. Fourth, the internal pressure of the single bubble is close to atmospheric pressure and is not negative pressure. In addition, since the huge number of single bubbles are bonded to each other by a collection of metal particles in which metal particles bonded to each other are stacked, the parts made of foamed metal have a certain mechanical strength based on the metallic bonding force of the stacked metal particles. In other words, the organic compounds covered with a highly viscous suspension are vaporized, and a balloon is formed in a state covered with the suspension, so the balloon has a pressure close to atmospheric pressure and is not negative pressure. In addition, since the balloons close to atmospheric pressure are bonded to each other by a collection of metal particles in which metal particles bonded to each other are stacked, the parts made of foamed metal have a certain mechanical strength based on the metallic bonding force of the metal particles. In other words, the collection of stacked metal particles is metallically bonded to six adjacent metal particles in the same layer, and to five to six adjacent metal particles in the upper and lower layers. For this reason, the parts made of foamed metal have a certain mechanical strength. Fifth, parts made of foamed metal are lighter than parts made of conventional foamed metal. That is, as described above, if the crushed first organic compound having a size of about 20 nm is vaporized to form a balloon, and a collection of metal fine particles having a size of about 50 nm is laminated in about seven layers on the surface of this balloon to form a single bubble, the weight of the balloon will be nearly 65% ​​lighter than a sphere with a radius of 1 μm formed from a bulk metal material. Therefore, parts made of foamed metal are lightweight. Sixth, parts made of metal foam have properties of sound insulation, sound absorption, heat insulation, vibration damping and shock absorption. In other words, parts made of metal foam are made by bonding countless balloons made of sealed gas with sizes of submicrons, and furthermore, because the balloons have properties of sound insulation, sound absorption, heat insulation, vibration damping and shock absorption, parts made of metal foam have excellent properties of sound insulation, sound absorption, heat insulation, vibration damping and shock absorption. Seventh, parts made of metal foam have the properties of various metals. In other words, metal compounds that precipitate metal particles by thermal decomposition precipitate metal particles of various materials, so the metals that make up the metal particles of parts made of metal foam can be freely changed depending on the application of the part. In the present invention, the foam metal parts are produced by forming balloons by vaporizing an organic compound without using a foaming agent. Also, the foam metal parts are produced by using as a raw material a collection of balloons whose surfaces are covered with the third suspension described in paragraph 7, so that the foam metal parts can be produced inexpensively by a process in which simple processes are continuously carried out. As a result, all seven issues listed in paragraph 6 were resolved.

[0011] A method for continuously producing a sheet of foamed metal using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method described in paragraph 7, comprising the steps of: Filling a container with a portion of the collection of balloons coated with the third suspension produced by the method described in paragraph 7; Then, for a first belt conveyor having a plane having a first feature that the width of the plane is wider than the width of the sheet of foam metal to be produced, a second feature that the plane contacts a vibration table, a third feature that the vibration table continuously applies three-directional vibrations consisting of vertical vibrations, widthwise vibrations, and lengthwise vibrations to the plane, and a fourth feature that the plane moves horizontally at a predetermined constant speed, the first belt conveyor is continuously operated, and further, a vibration exciter is continuously operated to apply the three-directional vibrations to the vibration table, and a predetermined amount of a collection of balloons whose surfaces are covered with the third suspension is continuously hung from the container to the front end of the plane of the first belt conveyor, the predetermined amount being the width of the sheet of foam metal to be produced. As a result, the collection of balloons whose surfaces are covered with the third suspension drips continuously onto the front end of the plane of the first belt conveyor, which corresponds to the width of the sheet of foam metal to be created, and as the plane moves horizontally at a constant speed, a coating having the width of the sheet of foam metal to be created is formed on the plane, and the vibrations in the three directions are continuously and alternately applied to the coating, so that the thickness of the coating becomes uniform. The collection of balloons covered with the third suspension that constitutes the coating is continuously rearranged within the collection of balloons, and the coating is formed into a sheet of uniform thickness, and the leading end of the sheet reaches the rear end of the plane of the first belt conveyor. Further, for a second belt conveyor having a plane that combines the first feature that the width of the plane is the same as the width of the plane of the first belt conveyor, the second feature that the plane moves horizontally at a predetermined speed, the third feature that the plane passes through a heat treatment device at the speed, the heat treatment device being made of an atmosphere in which the metal compound constituting the third suspension is thermally decomposed and heated to a temperature at which the thermal decomposition of the metal compound is completed, and the fourth feature that the front end of the plane is installed near the rear end of the plane of the first belt conveyor, the second belt conveyor is continuously operated in accordance with the operation of the first belt conveyor, whereby the leading end of the sheet that has reached the rear end of the plane of the first belt conveyor falls onto the front end of the plane of the second belt conveyor, and the plane of the second belt conveyor moves horizontally, so that the sheet enters the heat treatment device. When the sheet enters the heat treatment device, the temperature of the sheet rises, thermal decomposition of the metal compound constituting the third suspension begins, the metal compound decomposes into organic molecules and metal molecules, the organic molecules and the metal molecules mix with the second organic compound constituting the third suspension, and the mixed mixture covers the surface of the balloon, when the temperature of the sheet rises further, the second organic compound vaporizes, and a collection of the organic molecules and a collection of the metal molecules cover the surface of the balloon, when the temperature of the sheet rises further, vaporization accompanied by the heat of vaporization of the organic molecules begins, and the surface of the balloon is gradually covered with a collection of the metal molecules, when the temperature of the sheet rises further, the vaporization of the organic molecules is completed, the metal molecules covering the surface of the balloon gather together to form metal microparticles, the collection of metal microparticles precipitates all at once on the surface of the balloon, the collection of metal microparticles stacks and metal bonds with adjacent metal microparticles at the sites of contact, the collection of metal microparticles metallurgically stacks and covers the surface of the balloon, and adjacent metal microparticles covering the surface of the balloon metallurgically bond with each other, thereby bonding the balloons together via the collection of metal microparticles metallurgically bonded, and a sheet is formed consisting of a collection of balloons bonded with the collection of metal microparticles metallurgically bonded, and the sheet passes through the heat treatment device to continuously form a sheet consisting of a collection of balloons bonded with the collection of metal microparticles metallurgically bonded. A method for continuously producing a sheet of foamed metal using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method described in paragraph 7.

[0012] That is, the first belt conveyor is operated continuously, and furthermore, the vibrator is operated continuously, vibrations in three directions are applied to the vibration table, and vibrations in three directions are applied to the plane in contact with the vibration table. After this, the collection of balloons covered with the third suspension is hung from a container filled with a part of the collection of balloons covered with the third suspension to the front end of the plane of the horizontally moving first belt conveyor as the width of the sheet to be formed, and the plane of the first belt conveyor moves horizontally, so that a film-like sheet is formed on the plane of the first belt conveyor. In addition, the coating is continuously and alternately subjected to vibrations in three directions, and the group of balloons covered with the third suspension that constitutes the coating is repeatedly rearranged within the group of balloons so that the thickness of the coating becomes uniform, and the coating is formed into a sheet of uniform thickness, the leading edge of which reaches the rear end of the plane of the first belt conveyor. After this, the leading edge of the sheet falls onto the front end of the plane of a horizontally moving second belt conveyor, and as the plane of the second belt conveyor passes through a heat treatment device, the metal compound is thermally decomposed and a sheet consisting of a collection of balloons joined together by a collection of metal-bonded metal microparticles is continuously formed on the plane of the second belt conveyor. That is, similar to the case of manufacturing a part in the shape of the bottom surface of a container described in paragraph 10, when the collection of balloons covered with the third suspension passes through a heat treatment device, the collection of balloons covered with the third suspension increases in temperature, and the following phenomena occur in chronological order: The boiling point of the second organic compound is higher than the temperature at which the metal compound starts to decompose thermally and lower than the temperature at which the metal compound completes its decomposition. Therefore, when the metal compound starts to decompose thermally, the metal compound decomposes into organic molecules and metal molecules, and the organic molecules and metal molecules are mixed in the second organic compound, and the mixed mixture covers the surface of the balloon. After this, the second organic compound vaporizes, and a group of organic molecules and a group of metal molecules cover the surface of the balloon. Furthermore, when the organic molecules take the heat of vaporization and start to vaporize, a group of metal molecules gradually covers the surface of the balloon. Furthermore, when the vaporization of the organic molecules is completed, the metal molecules gather to form metal fine particles, and a group of metal fine particles with a size of about 50 nm precipitates all at once on the surface of the balloon, and the group of metal fine particles is layered. The group of metal fine particles is metallically bonded at the site where adjacent metal fine particles contact each other. Furthermore, adjacent metal microparticles covering the surface of the balloons are metallically bonded to each other, so that the balloons are joined together via the collection of metallically bonded metal microparticles, and a sheet made up of the collection of balloons is passed through a heat treatment device to form a continuous sheet. Here, it is assumed that a collection of metal fine particles having a size of about 50 nm and bonded with metal is laminated in about 7 layers to cover the surface of the balloon. In addition, the laminated collection of metal fine particles is metal-bonded with 6 adjacent metal fine particles in the same layer, and with 5-6 adjacent metal fine particles in the upper and lower layers. Therefore, the collection of metal fine particles laminated with metal-bonded metal fine particles has airtightness against the gas that forms the balloon, and the gas of the balloon is kept inside the balloon. As a result, the balloon covered with the collection of metal fine particles bonded with metal, that is, the single bubble, has a size of about 1 micron. That is, when the crushed first organic compound having a size of about 20 nm is vaporized, a balloon with a radius of about 650 nm is formed. In addition, if a collection of metal fine particles having a size of about 50 nm is laminated in 7 layers on the surface of the balloon, the thickness of the collection of metal fine particles will be about 350 nm. On the other hand, if the interior of a metal sphere with a radius of 1000 nm is hollow and occupies 65% of the volume, the weight of the metal sphere will be reduced by nearly 65%. Therefore, if a single bubble is formed by laminating seven layers of metal particles with a size of about 50 nm on the surface of a balloon with a radius of about 650 nm, the weight of the metal sphere with a radius of 1000 nm will be reduced by 65%. Therefore, the weight reduction effect of a metal foam consisting of a collection of single bubbles is significant. The foam metal sheet manufactured by the method described above provides the seven functional effects as the foam metal part described in paragraph 10. Moreover, the foam metal sheet of the present invention solves all of the seven problems described in paragraph 6 as the foam metal part described in paragraph 10.

[0013] A method for producing a container or part made of foam metal in a gap of a mold by using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method described in paragraph 7, comprising the steps of: Assemble an outer mold and an inner mold to form a mold, and form a gap between the outer mold and the inner mold. Then, fill the gap in the mold with a part of the group of balloons covered with the third suspension produced by the method described in paragraph 7. Then, drop the mold 2-3 times onto a flat surface at a distance of 5-10 cm, and apply a drop impact force 2-3 times to the group of balloons covered with the third suspension filled in the gap in the mold, thereby increasing the packing density of the group of balloons covered with the third suspension in the gap in the mold. Thereafter, the mold is transferred to a heat treatment device, and the mold is exposed to an atmosphere in which the metal compound constituting the third suspension is thermally decomposed, and the temperature is further increased to a temperature at which the thermal decomposition of the metal compound is completed. As a result, the temperature of the mold is raised, and first, thermal decomposition of the metal compound constituting the third suspension begins, the metal compound decomposes into organic molecules and metal molecules, the organic molecules and the metal molecules mix with the second organic compound constituting the third suspension, and this mixed mixture covers the surface of the balloon, as the temperature of the mold is further raised, the second organic compound vaporizes, and a collection of the organic molecules and a collection of the metal molecules cover the surface of the balloon, as the temperature of the mold is further raised, vaporization of the organic molecules accompanied by the heat of vaporization begins, and the surface of the balloon is gradually covered with a collection of the metal molecules, as the temperature of the mold is further raised, the vaporization of the organic molecules is completed, and the The metal molecules covering the surface of the balloon gather together to form metal microparticles, and the collection of metal microparticles precipitates all at once on the surface of the balloon, the collection of metal microparticles stacks and metal bonds with adjacent metal microparticles at the sites of contact, the collection of metal-bonded metal microparticles stacks and covers the surface of the balloon, adjacent metal microparticles covering the surface of the balloon metal-bond with each other, the balloons are bonded to each other via the collection of metal microparticles that are metal-bonded, and the collection of balloons bonded by the collection of metal-bonded metal microparticles forms a container or part in the gaps of the mold, and the size of the gaps in the mold is the wall thickness of the container or part. Thereafter, the inner mold is separated from the mold, the separated inner mold is taken out, and the container or the part is taken out from the outer mold. A method for producing a container or part made of foam metal, comprising using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method described in paragraph 7, and producing a container or part made of foam metal in a gap of a mold.

[0014] That is, a part of the group of balloons covered with the third suspension produced by the method described in paragraph 7 is filled into the gap between the outer and inner dies, and then the die is subjected to a drop impact force 2-3 times to increase the packing density of the group of balloons covered with the third suspension in the gap between the dies. Then, the die is moved to a heat treatment device, and the die is exposed to an atmosphere in which the metal compound constituting the third suspension is thermally decomposed, and the temperature is raised to a temperature at which the thermal decomposition of the metal compound is completed. As a result, a container or part made of foamed metal having a shape corresponding to the shape of the gap between the dies and a wall thickness corresponding to the gap between the dies is formed in the gap between the dies. For example, a container made of a cylinder, a container made of a square tube, or a container or part made of a square tube, or a container or part made of various shapes according to the shape of the gap between the dies is formed. In addition, the wall thickness of the container or part is determined by the gap between the dies. That is, the gaps between the molds are filled with the collection of balloons covered with the third suspension, the molds are moved to a heat treatment device, the molds are exposed to an atmosphere in which the metal compounds constituting the third suspension are thermally decomposed, and the temperature is raised to a temperature at which the thermal decomposition of the metal compounds is completed. At this time, the collection of balloons covered with the third suspension filled in the gaps between the molds is heated, as in the case of manufacturing a part on the bottom surface of a container in the shape of the bottom surface described in paragraph 10, and the following phenomena occur in chronological order. The boiling point of the second organic compound is higher than the temperature at which the metal compound starts to decompose thermally and lower than the temperature at which the metal compound completes its decomposition. Therefore, when the metal compound starts to decompose thermally, the metal compound decomposes into organic molecules and metal molecules, and the organic molecules and metal molecules are mixed in the second organic compound, and the mixed mixture covers the surface of the balloon. After this, the second organic compound vaporizes, and a group of organic molecules and a group of metal molecules cover the surface of the balloon. Furthermore, when the organic molecules take the heat of vaporization and start to vaporize, a group of metal molecules gradually covers the surface of the balloon. Furthermore, when the vaporization of the organic molecules is completed, the metal molecules gather to form metal fine particles, and a group of metal fine particles with a size of about 50 nm precipitates all at once on the surface of the balloon, and the group of metal fine particles is layered. The group of metal fine particles is metallically bonded at the site where adjacent metal fine particles contact each other. Furthermore, adjacent metal fine particles covering the surface of the balloons are metallically bonded to each other, so that the balloons are joined together via the collection of metallic fine particles that are metallically bonded, and a container or part consisting of the collection of balloons is formed in the gaps of the mold, with the shape of the container or part being the shape of the gaps of the mold and the size of the gaps of the mold being the wall thickness of the container or part. After this, the inner mold is separated from the mold, and the container or part consisting of the collection of balloons is taken out from the separated mold. Here, it is assumed that a collection of metal fine particles having a size of about 50 nm and bonded with metal is laminated in about 7 layers to cover the surface of the balloon. In addition, the laminated collection of metal fine particles is metal-bonded with 6 adjacent metal fine particles in the same layer, and with 5-6 adjacent metal fine particles in the upper and lower layers. Therefore, the collection of metal fine particles laminated with metal-bonded metal fine particles has airtightness against the gas that forms the balloon, and the gas of the balloon is kept inside the balloon. As a result, the balloon covered with the collection of metal fine particles bonded with metal, that is, the single bubble, has a size of about 1 micron. That is, when the crushed first organic compound having a size of about 20 nm is vaporized, a balloon with a radius of about 650 nm is formed. In addition, if a collection of metal fine particles having a size of about 50 nm is laminated in 7 layers on the surface of the balloon, the thickness of the collection of metal fine particles will be about 350 nm. On the other hand, if the interior of a metal sphere with a radius of 1000 nm is hollow and occupies 65% of the volume, the weight of the metal sphere will be reduced by nearly 65%. Therefore, if a single bubble is formed by laminating seven layers of metal particles with a size of about 50 nm on the surface of a balloon with a radius of about 650 nm, the weight of the metal sphere with a radius of 1000 nm will be reduced by 65%. Therefore, the weight reduction effect of a metal foam consisting of a collection of single bubbles is significant. A container or part made of foamed metal produced by the method described above provides the seven functional effects as the part made of foamed metal described in paragraph 10. Moreover, a container or part made of foamed metal according to the present invention solves all of the seven problems described in paragraph 6 as the part made of foamed metal described in paragraph 10.

[0015] The method for imparting new metallic properties to a part, sheet, container or part made of a metal foam produced by the method described in each of paragraphs 9, 11 and 13 is as follows: A metal compound is produced by pyrolysis to precipitate a new metal different from the metal constituting the part, sheet, container or part made of foamed metal produced by the method described in each of paragraphs 9, 11 and 13, and the metal compound is dispersed in methanol to prepare a methanol dispersion of the metal compound. further comprising mixing an organic compound having a first property of being soluble or miscible in methanol, a second property of being more viscous than methanol, and a third property of having a boiling point higher than the boiling point of methanol and lower than the thermal decomposition temperature of the metal compound, into the methanol dispersion of the metal compound, and filling a container with the mixture in which the organic compound is dissolved or mixed into the methanol dispersion of the metal compound. Furthermore, a part, sheet, container or component made of foam metal is manufactured by each of the methods described in paragraphs 9, 11 and 13, the whole part, sheet, container or component made of foam metal is immersed in the mixed liquid in the container, the part, sheet, container or component made of foam metal is then removed from the container, the part, sheet, container or component made of foam metal is exposed to an atmosphere in which the metal compound is thermally decomposed, and the temperature is further increased to a temperature at which the metal compound is thermally decomposed. This causes a collection of metal microparticles made of the new metal to precipitate all at once on the collection of metal-bonded metal microparticles that form the surface of a part, sheet, container or component made of the metal foam, and the new metal microparticles form metal bonds at the sites where they come into contact with each other, and the metal-bonded new collection of metal microparticles covers the surface of the part, sheet, container or component made of the metal foam, thereby imparting the properties of the new metal to the part, sheet, container or component made of the metal foam.This is a method of imparting the properties of a new metal to a metal foam.

[0016] In other words, by manufacturing a part, sheet, container or component made of metal foam using each of the methods described in paragraphs 9, 11 and 13, and covering the surface of the part, sheet, container or component made of metal foam with a collection of metallically bonded metal microparticles made of a new metal different in material from the metal constituting the part, sheet, container or component made of metal foam, the properties of the new metal will be imparted to the part, sheet, container or component made of metal foam. That is, a metal compound that precipitates a new metal different from the metal constituting the part, sheet, container, or part made of foam metal by thermal decomposition is dispersed in methanol to prepare a methanol dispersion of the metal compound. An organic compound having three properties is mixed into the methanol dispersion of the metal compound. After that, the whole part, sheet, container, or part made of foam metal produced by each of the methods described in paragraphs 9, 11, and 13 is immersed in the mixed liquid, and then the part, sheet, container, or part made of foam metal is taken out from the mixed liquid. Furthermore, the part, sheet, container, or part made of foam metal is exposed to an atmosphere in which the metal compound is thermally decomposed, and further, the temperature is raised to a temperature at which the metal compound is thermally decomposed. As a result, clusters of metal microparticles made of a new metal are precipitated all at once on the clusters of metal-bonded metal microparticles that form the surface of a part, sheet, container or component made of foam metal, and the new metal microparticles are metal-bonded at the sites where they come into contact with each other, and the new clusters of metal-bonded metal microparticles cover the surface of the part, sheet, container or component made of foam metal, thereby imparting the properties of the new metal to the part, sheet, container or component made of foam metal. For example, by using the methods described in paragraphs 9, 11, and 13 to manufacture a part, sheet, container, or component made of foam metal consisting of an assembly of aluminum fine particles, and covering the surface of the part, sheet, container, or component made of foam metal with an assembly of metallically bonded silver fine particles, the foam metal can be given the properties of silver. In this case, by using a reduced amount of silver compound that precipitates silver by thermal decomposition, and by depositing a small number of silver fine particles on the surface of the part, sheet, container, or component made of foam metal consisting of an assembly of aluminum fine particles, the foam metal can be given the properties of silver, for example, the catalytic action of silver, by using a small amount of silver compound compared to the aluminum compound that forms the foam metal, if two layers of silver fine particles are deposited and the metallically bonded assembly of silver fine particles cover the foam metal. Furthermore, by using the methods described in paragraphs 9, 11, and 13 to manufacture a part, sheet, container, or component made of a metal foam consisting of an assembly of aluminum fine particles, and covering the surface of the metal foam with an assembly of nickel fine particles that are metallically bonded, ferromagnetic properties can be imparted to the non-magnetic metal foam consisting of an assembly of aluminum fine particles. In this case, by reducing the amount of nickel compound that precipitates nickel by thermal decomposition and covering the surface of the metal foam consisting of an assembly of aluminum fine particles with a small number of layers, for example, two layers of nickel fine particles that are metallically bonded, the metal foam can be imparted with ferromagnetic properties by using a small amount of nickel compound compared to the aluminum compound that forms the metal foam.

[0017] a method for producing a raw material used in producing a foamed metal consisting of a collection of single bubbles as described in paragraph 7, comprising the steps of: the metal compound described in paragraph 7 is a metal octylate compound; the first organic compound described in paragraph 7 is one of crotonic acid, angelic acid, or tiglic acid, which belong to monounsaturated carboxylic acids; and the second organic compound described in paragraph 7 is diethylene glycol, which belongs to dihydric alcohols; the method for producing a raw material used in producing a foamed metal consisting of a collection of single bubbles as described in paragraph 7, comprising the steps of: using the metal compound described in paragraph 7 as the metal compound, using the one monounsaturated carboxylic acid as the first organic compound described in paragraph 7, and using the diethylene glycol as the second organic compound described in paragraph 7, according to the method described in paragraph 7;

[0018] That is, when the metal octylate compound is heat-treated at 290°C in an air atmosphere, the metal precipitates. In addition, it disperses in methanol at nearly 10% by weight and does not dissolve in methanol. Therefore, the metal octylate compound can be used as a metal compound that combines the two properties described in paragraph 7. In addition, when the metal octylate compound exceeds 228°C, which is the boiling point of octylate, the bond between the oxygen ion and the metal ion that constitutes the carboxyl group is first broken, and the compound is separated into octylate and metal. Furthermore, since octylate is a saturated fatty acid and does not have an unsaturated structure in which carbon atoms are in excess of hydrogen atoms, the octylate absorbs the heat of vaporization and vaporizes, and the metal precipitates at 290°C when the vaporization is completed. Therefore, the metal octylate compound is heat-treated in an air atmosphere. In contrast, any of the monounsaturated carboxylic acids, crotonic acid CH3(CH)2COOH, angelic acid CH3CH:C(CH3)COOH, and tiglic acid CH3CH:C(CH3)COOH, which belong to the monounsaturated carboxylic acids, has a first property of a melting point higher than 30°C and a second property of a boiling point lower than 228°C, the temperature at which the thermal decomposition of octylic acid compounds begins, which precipitates metals by thermal decomposition. That is, crotonic acid has a melting point of 72°C and a boiling point of 189°C. Angelic acid has a melting point of 46°C and a boiling point of 185°C. Tiglic acid has a melting point of 64°C and a boiling point of 199°C. These three types of monounsaturated carboxylic acids have two properties: a melting point higher than 30°C and a boiling point lower than the temperature at which the thermal decomposition of octylic acid metal compounds begins, which precipitates metals by thermal decomposition. Thus, these three monounsaturated carboxylic acids can be used as the first organic compound described in paragraph 7. Furthermore, diethylene glycol (CH2CH2OH)2O, which belongs to the dihydric alcohol, has a melting point of -10°C, a boiling point of 244°C, and a viscosity of 36 mPa·sec at 20°C. Crystals of metal octylate compounds do not disperse or dissolve in diethylene glycol. Therefore, diethylene glycol can be used as the second organic compound that has the four properties described in paragraph 7, namely a melting point lower than 10°C, a boiling point higher than 228°C at which the thermal decomposition of metal octylate compounds begins and lower than 290°C at which the decomposition of metal octylate compounds is completed, a viscosity of 35 mPa·sec or more at 20°C, and crystals of metal octylate compounds do not disperse or dissolve. The crystals of the three monounsaturated carboxylic acids have the property of neither dissolving nor dispersing in a diethylene glycol methanol solution. Therefore, when a first suspension in which a crystal cluster of a metal octylate compound is dispersed in a diethylene glycol methanol solution is mixed with a crushed crystal cluster of the three monounsaturated carboxylic acids, a second suspension is produced. When the second suspension is decompressed to a pressure lower than the saturated vapor pressure of the three monounsaturated carboxylic acids in a vacuum bell jar, a cluster of balloons whose surfaces are covered with the third suspension is produced in the container in the vacuum bell jar. As a result, a raw material used for producing a foam metal consisting of a cluster of single bubbles is produced. Next, the properties of the above-mentioned octylic acid metal compound will be described. As described in paragraph 7, the crystal size of the metal compound is smaller than 100 nm. When such crystals of octylic acid metal compound are thermally decomposed, they are separated into octylic acid and metal, and after the octylic acid is vaporized, metal nanoparticles with a size of about 50 nm are precipitated. That is, among the ions constituting the octylic acid metal compound, the metal ion is the largest. Therefore, in the octylic acid metal compound in which the oxygen ion constituting the carboxyl group of octylic acid is covalently bonded to the metal ion, the distance between the oxygen ion constituting the carboxyl group and the metal ion is longer than the distance between other ions. When the octylic acid metal compound having such molecular structure is heat-treated in an air atmosphere, when the temperature exceeds 228°C, the boiling point of octylic acid, the bond between the oxygen ion constituting the carboxyl group and the metal ion is first broken, and the compound is separated into octylic acid and metal. Furthermore, since octylic acid is a saturated fatty acid, it does not have an unsaturated structure in which carbon atoms are in excess of hydrogen atoms, so octylic acid takes the heat of vaporization and vaporizes, and the metal precipitates at 290°C when the vaporization is completed. In other words, the carboxylate anion (R-COO - ), but metal carboxylate compounds that are covalently bonded to metal ions precipitate metals through thermal decomposition. Such metal carboxylate compounds are, in order of decreasing thermal decomposition temperature at which metals precipitate, metal octylate compounds, metal laurate compounds, and metal stearates compounds. Therefore, by using metal octylate compounds, which have the lowest thermal decomposition temperature, parts, sheets, containers, or parts made of foamed metal as described in paragraphs 9, 11, and 13, can be manufactured inexpensively. Note that metal laurate compounds and metal stearates compounds, like metal octylate compounds, are dispersed in methanol at nearly 10% by weight and do not dissolve in methanol. That is, the boiling point of lauric acid is 296°C, and the thermal decomposition temperature of metal laurate compound is 360°C. However, the thermal decomposition temperatures of metal laurate compound and metal stearate compound are higher than that of metal octylate compound. Therefore, it is desirable to use metal octylate compound as a raw material for depositing metal. In addition, compared to carboxylate metal compounds made from saturated fatty acids, carboxylate metal compounds made from unsaturated fatty acids have an excess of carbon atoms relative to hydrogen atoms, and therefore, when thermally decomposed, metal oxides, for example, in the case of copper oleate, cuprous oxide Cu2O and cupric oxide CuO are precipitated simultaneously, and processing costs are required to reduce the cuprous oxide and cupric oxide to copper. In particular, cuprous oxide must be oxidized to cupric oxide in an atmosphere richer in oxygen than the air atmosphere, and then reduced to copper in a reducing atmosphere, which increases processing costs. For this reason, the carboxylate anion (R-COO) of carboxylate of saturated fatty acids is used as a metal compound that precipitates metals when thermally decomposed. - ), but metal carboxylate compounds which are covalently bonded to a metal ion are preferred. Furthermore, metal octylate compounds are inexpensive industrial chemicals that can be easily synthesized. That is, when octylic acid is reacted with a strong alkali, an alkali metal octylate compound is produced. When the alkali metal octylate compound is then reacted with an inorganic metal compound, metal octylate compounds made of various metals are produced. Also, octylic acid is a versatile organic acid. Metal octylate compounds are the cheapest organometallic compounds among organometallic compounds. Next, the properties of crotonic acid, angelic acid and tiglic acid which belong to the above-mentioned monounsaturated carboxylic acids will be explained. Crotonic acid is a general-purpose industrial chemical used as a raw material for paints, coatings, and adhesives. Angelic acid is a general-purpose industrial chemical used as a raw material for angelic acid esters used in acyclic or carbocyclic compound-containing medicines. Tiglic acid is a general-purpose industrial chemical used as a raw material for photosensitive resin compositions and adhesives. These three monounsaturated carboxylic acids are therefore inexpensive organic compounds. Furthermore, diethylene glycol, which belongs to the above-mentioned dihydric alcohol, will be described. Diethylene glycol is a general-purpose industrial chemical that is used in antifreeze, brake fluid, lubricants, inks, tobacco additives (humectants), fabric softeners, cork plasticizers, adhesives, paper, packaging materials, paints, etc. [Brief description of the drawings]

[0019] [Figure 1] This is a schematic diagram of an enlarged portion of a foam metal consisting of a collection of individual bubbles, in which a collection of metallically bonded copper microparticles forms individual bubbles, and adjacent copper microparticles form metallic bonds to join the individual bubbles. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLES

[0020] This example involves the manufacture of a collection of balloons coated with the third suspension described in paragraph 7. The first organic compound was crotonic acid (a product of Fujifilm Wako Pure Chemical Industries, Ltd.), which has a melting point of 72°C and a boiling point of 189°C. The second organic compound was diethylene glycol (a product of Mitsubishi Chemical Corporation), which has a melting point of -10°C, a boiling point of 244°C, and a viscosity of 36 mPa·s at 20°C. The metal compound was copper octylate Cu[OOCCH(C 2 H 5 )C 4 H 9 ] 2 (Product of Fujifilm Wako Pure Chemical Industries, Ltd.) was used. Note that, in the air, copper octylate begins to decompose at 228°C, and the decomposition is complete at 290°C, resulting in the precipitation of copper. First, 10 g (equivalent to 0.12 moles) of crotonic acid was dissolved in 30 cc of methanol to prepare a methanol solution of crotonic acid, and the methanol solution of crotonic acid was filled into a container in a vacuum bell jar. The vacuum bell jar was sealed and a water-sealed vacuum pump was operated to reduce the pressure inside the vacuum bell jar to 80 mmHg, which is lower than the saturated vapor pressure of 100 mmHg of methanol at 20°C, and methanol was vaporized from the methanol solution of crotonic acid, causing a collection of crotonic acid crystals to precipitate in the container in the vacuum bell jar. After this, the vacuum bell jar was opened to atmospheric pressure, and the collection of crotonic acid crystals was removed from the container in the vacuum bell jar. The vaporized methanol was recovered and reused. The crotonic acid crystals were then packed into a 3cm x 3cm x 2cm container. A 3cm x 3cm x 1cm plate was then placed on top of the crotonic acid crystals, and five 0.6kg weights were placed on the plate at equal intervals. The weights were then removed, and an impact acceleration of 0.2G was repeatedly applied to the sides and bottom of the container in three directions: front-back, left-right, and up-down. After repeating this process of applying a compressive load and impact acceleration three times, the weight was placed on the plate, but since there was no movement of the plate, it was considered that the crushing of the crotonic acid crystals was complete. Furthermore, 350 kg (corresponding to 1000 moles) of copper octylate was dispersed in methanol to a concentration of 10% by weight, and the temperature of the methanol dispersion of copper octylate was then raised to 65°C to vaporize the methanol, causing the crystals of copper octylate to precipitate. The vaporized methanol was then recovered and reused. Next, 424 kg (equivalent to 4000 moles) of diethylene glycol was dissolved in 2000 kg of methanol, and the resulting solution was mixed with the clusters of copper octylate crystals to produce the first suspension described in paragraph 7. The viscosity of the diethylene glycol methanol solution is close to 5.7 mPa·sec at 20°C. Furthermore, the first suspension was mixed with a cluster of crushed crystals of crotonic acid to prepare a second suspension. Furthermore, the second suspension was filled into a container, and the container was heated to 35° C. to increase the vapor pressure of the crushed crystals of crotonic acid in the second suspension. After this, the second suspension was filled into a container in a vacuum bell jar, the vacuum bell jar was sealed, and the dry pump was operated to reduce the pressure in the vacuum bell jar to 100 Pascal, which is lower than the saturated vapor pressure of the first organic compound at 35° C. As a result, methanol was evaporated from the methanol solution of diethylene glycol, and the third suspension in which the cluster of copper octylate crystals was dispersed in diethylene glycol covered the surface of the crushed crystals of crotonic acid. Next, the crushed crystals of crotonic acid were evaporated, and the gas of crotonic acid formed a balloon, and the surface of the balloon was covered with the third suspension. As a result, a cluster of balloons covered with the third suspension was produced. The evaporated methanol was recovered and reused. In this embodiment, in order to form the foamed metal with a collection of copper fine particles, copper octylate, which precipitates copper by thermal decomposition, was used as the metal compound. However, the metal fine particles that form the foamed metal are not limited to copper fine particles. Since the metal octylate compound is a metal compound made of various metals, the foamed metal can be formed by a collection of various metal fine particles. . EXAMPLES

[0021] This example is an example in which a part made of foamed metal is manufactured on the bottom surface of a container in the shape of the bottom surface by using as a raw material a collection of balloons whose surfaces are covered with the third suspension described in paragraph 9. Here, a rectangular plate is manufactured on the bottom surface of a container in the shape of the bottom surface by using the collection of balloons covered with the third suspension manufactured in Example 1. A 10cm x 60cm x 2cm container was filled with a portion of the balloon cluster covered with the third suspension prepared in Example 1, and the container was moved to a heat treatment device in an air atmosphere, heated to 210°C at a heating rate of 30°C / min, then heated to 290°C at a heating rate of 10°C / min, and left at 290°C for 1 minute, and the container was removed from the heat treatment device. After this, an impact acceleration of 0.3G was applied to four points on the bottom surface of the container, and a 10cm x 60cm plate was peeled off from the container. Three such plates were produced. First, the sheet was allowed to fall from a height of 2m, but it did not break, indicating that the sheet has a certain strength. Next, the surface and cross section of the sample were observed using an electron microscope. An extremely low accelerating voltage SEM from JFE Techno-Research Corporation was used as the electron microscope. This device allows observations at extremely low accelerating voltages starting from 100V, and has the advantage of allowing the sample to be observed directly without forming a conductive coating on the sample. First, the secondary electron beam between 900-1000V of the reflected electron beam from the sample surface was extracted and image processing was performed to observe the sample surface. A collection of 40-60nm granular particles covered the entire surface of the sample. In addition, from the image of the secondary electron beam between 900-1000V of the reflected electron beam from the cross section of the sample, the collection of granular particles covered the balloon, and the collection of balloons formed the sample. The size of the balloon was about 650nm, the thickness of the collection of granular particles covering the balloon was about 350nm, and the balloons covered by the collection of granular particles were connected by the collection of granular particles. Next, the energy and intensity of the characteristic X-rays were image processed to analyze the type of element that constitutes the granular particles in the cross section of the sample. It was found to be copper atoms. Observation of the sample showed that a balloon with a size of about 650 nm was covered with a cluster of 40-60 nm copper particles with a thickness of about 350 nm, and the balloons covered with the clusters of copper particles were connected with each other by the clusters of copper particles. Figure 1 shows a schematic enlarged view of a part of the cross section of the sample. 1 is the balloon, and 2 is the cluster of copper particles. The sheet material thus produced is a metal foam consisting of an aggregate of individual bubbles, with the balloons making up nearly two-thirds of the volume of the metal foam. As a result, not only do the balloons contribute to making the metal foam lighter, but the sheet material also has excellent sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption properties, due to the balloons' properties. In addition, because the metal foam is made up of aggregates of copper particles, the sheet material has the properties of copper. The size of the balloons is determined by the size of the crushed crotonic acid crystals. The thickness of the copper particles covering the balloons is determined by the amount of copper octylate used. The shape of the sample is determined by the shape of the bottom of the container filled with the collection of balloons covered with the third suspension. Therefore, the foam metal can be formed not only in the shape of a rectangle, but also in the shape of a disk or a polygon on the bottom of the container. . EXAMPLES

[0022] This embodiment is an example of continuously producing a sheet made of foam metal using a collection of balloons whose surfaces are covered with the third suspension described in paragraph 11 as a raw material. A vibration table was placed so as to be in contact with the plane of a first conveyor belt having a length of 2 m, and a vibration exciter was operated to continuously apply a vibration acceleration of 0.2 G to the plane of the first conveyor belt via the vibration table in three directions, namely, the vertical direction, the width direction, and the length direction, alternately. After this, a collection of balloons whose surfaces were covered with the third suspension was hung at a rate of 5 g per second on the front end of the plane of the first conveyor belt over the entire width of the plane, which was 10 cm, and the first conveyor belt was moved at a speed of 5 cm per second to form a sheet consisting of a collection of balloons whose surfaces were covered with the third suspension over the entire plane. The leading edge of the sheet that has reached the rear end of the plane of the first belt conveyor is transferred to the plane of the second belt conveyor, and the sheet is moved on the plane of the second belt conveyor, and the sheet is continuously passed through the heat treatment device in the air atmosphere. Note that the heat treatment device has a temperature gradient, and by controlling the moving speed of the belt conveyor, the sheet is heated to 210°C at a heating rate of 30°C / min, and then heated to 290°C at a rate of 10°C / min, as in Example 2, and is left at 290°C for 1 minute, after which the leading edge of the sheet is sent out from the heat treatment device. First, the sheet was cut into pieces 20cm wide and then allowed to drop from a height of 2m without being destroyed. This indicates that the sheet has a certain strength. After this, the cut surface of the sheet was observed with an electron microscope. The electron microscope was the same as that used in Example 2. As in Example 2, a secondary electron beam between 900-1000V of the reflected electron beam from the surface of the sheet was taken out to observe the surface of the sample. A collection of 40-60 nm granular fine particles covered the entire surface of the sample. Also, as in Example 2, from the image of the secondary electron beam between 900-1000V of the reflected electron beam from the cross section of the sample, the collection of granular fine particles covered the balloon, and the collection of balloons formed the sample. The size of the balloon was about 650 nm, the thickness of the collection of granular fine particles covering the balloon was about 350 nm, and the balloons covered by the collection of granular fine particles were connected to each other by the collection of granular fine particles. Observation of the sheet revealed that, as in Example 2, balloons approximately 650 nm in size were covered with clusters of copper particles approximately 350 nm in size and 40-60 nm in size, and the balloons covered with the clusters of copper particles were connected to each other by the clusters of copper particles. Therefore, the produced sheet is a metal foam consisting of an aggregate of individual bubbles, as in Example 2, and the balloons make up nearly two-thirds of the volume of the metal foam. Therefore, not only do the balloons contribute to making the metal foam lighter, but the sheet also has excellent sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption properties, as a result of the balloons having such properties. In addition, because the aggregate of copper fine particles constitutes the metal foam, the sheet has the properties of copper. . EXAMPLES

[0023] This example is an example of manufacturing a cylinder made of foam metal using a collection of balloons whose surfaces are covered with the third suspension described in paragraph 13 as a raw material. The two molds were assembled so that a gap of 5 mm was formed between the outer mold with an inner diameter of 20 cm and the inner mold with an outer diameter of 19 cm, and a part of the collection of balloons covered with the third suspension prepared in Example 1 was filled into the 5 mm gap. Then, the mold was dropped twice from a height of 5 cm to increase the packing density of the collection of balloons covered with the third suspension in the gap between the molds. Then, the mold was moved to the heat treatment device used in Example 3, and the collection of balloons covered with the third suspension in the mold was heat-treated under the same heat treatment conditions as in Example 3. Then, the inner mold was separated from the assembled molds, the separated inner mold was taken out, and a cylinder with a wall thickness of 5 mm was taken out from the outer mold. First, the cylinder was allowed to fall from a height of 2m, but it did not break. This shows that the cylinder has a certain strength. A part of the top of the cylinder was cut, and the cut surface was observed with an electron microscope in the same manner as in Examples 2 and 3. As a result, as in Examples 2 and 3, a balloon having a size of about 650 nm was covered with a collection of copper fine particles having a size of 40-60 nm and a thickness of about 350 nm, and the balloons covered with the collection of copper fine particles were connected to each other by the collection of copper fine particles. Therefore, as in Examples 2 and 3, the created cylinder is a metal foam consisting of a collection of single bubbles, and the balloon occupies nearly 2 / 3 of the volume of the metal foam. Therefore, not only does the balloon contribute to weight reduction of the metal foam, but the balloon has sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption, so that the cylinder has excellent sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption properties. In addition, since the collection of copper fine particles constitutes the metal foam, the cylinder has the properties of copper. The container made of foam metal is not limited to a cylinder. It is possible to manufacture a container or a part having a shape corresponding to the shape of the gap formed by the mold and a wall thickness according to the size of the gap. The above describes the manufacturing of plates, sheets, and cylinders made of foamed metal as examples. Foamed metal is composed of a collection of individual bubbles, so that foamed metal plates, sheets, and cylinders are not only lighter in weight than bulk materials, but also have the properties of balloons related to sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption. In addition, the metal particles that make up the foamed metal have the metallic properties. . EXAMPLES

[0024] This embodiment relates to a method of imparting new metallic properties to a part, sheet, container or component made of the foam metal described in paragraph 15, and imparts the properties of silver to a foam metal plate made of a collection of copper microparticles prepared in Example 2. Diamine silver chloride (a product of Tanaka Kikinzoku Kogyo Co., Ltd.) was used as the silver compound. Diamine silver chloride is an inorganic metal compound that has a silver complex ion in which ammonia is coordinated to a silver ion, and its composition formula is [Ag(NH 3 ) 2 ]Cl, which decomposes thermally at 180°C in a hydrogen atmosphere to precipitate silver. First, 230 g (corresponding to 1 mole) of diamine silver chloride and 350 g of methanol were charged into a container, and the methanol was stirred to disperse the diamine silver chloride in the methanol. Furthermore, 1-propanol CH 3 (CH 2 ) 2 200 g of OH was mixed into a methanol dispersion of diamine silver chloride. This mixture was filled into a container measuring 11 cm x 61 cm x 2 cm. The plate material prepared in Example 2 was immersed in the container, and then the plate material was removed from the container. The viscosity of the mixture at 20°C increased to 1.1 mPa·sec. The plate material was placed in a heat treatment device whose temperature had been raised to 180° C. in a hydrogen atmosphere, and was left in the heat treatment device for 5 minutes, after which the plate material was taken out. First, the board was allowed to drop from a height of 2 m, but the board did not break. Thereafter, the surface and cross section of the plate were observed under an electron microscope in the same manner as in Examples 2, 3, and 4. The surface of the plate was covered with silver particles of 40-60 nm. In addition, observation of the cross section of the plate showed that the surface of the plate was covered with 2-3 layers of silver particles and metal-bonded silver particles. Therefore, the foam metal plate made of a collection of copper particles prepared in Example 2 is endowed with the properties of silver, for example, catalytic action. Above, an example was shown in which the surface of a metal foam consisting of a collection of copper particles was covered with a collection of silver particles. However, the metal particles covering the surface of the metal foam are not limited to silver particles. Since metal compounds precipitate various metals by thermal decomposition, the surface of the metal foam can be covered with a collection of various metal particles, and the properties of various metals can be imparted to the metal foam. . [Explanation of symbols]

[0025] 1. Balloon 2. Cluster of copper particles

Claims

1. A method for producing a raw material for use in producing a metal foam consisting of an aggregate of single cells, in which aggregates of metallically bonded metal particles cover the surface of single cells and the aggregates of metallically bonded metal particles covering the surface bond the single cells together, comprises the steps of: a first organic compound having a first property of a melting point higher than 30° C., a second property of a boiling point lower than the temperature at which thermal decomposition of a metal compound that precipitates a metal by thermal decomposition begins, and a third property of the crystals not dissolving or dispersing in a methanol solution of a second organic compound is dissolved in methanol to prepare a methanol solution of the first organic compound, the methanol solution of the first organic compound is then filled into a container in a vacuum bell jar, the vacuum bell jar is sealed and a vacuum pump is operated to reduce the pressure in the vacuum bell jar to a pressure lower than the saturated vapor pressure of the methanol, the methanol is vaporized from the methanol solution of the first organic compound, a collection of crystals of the first organic compound is precipitated in the container in the vacuum bell jar, the vacuum bell jar is opened to atmospheric pressure, and the collection of crystals of the first organic compound is taken out from the container in the vacuum bell jar; Furthermore, the collection of crystals of the first organic compound is filled into a new container, and a plate material that covers the entire surface of the collection of crystals of the first organic compound is placed on the collection of crystals of the first organic compound. After this, a compressive load is applied to the entire surface of the plate material to crush the crystals of the first organic compound in the new container. Furthermore, impact accelerations are repeatedly applied to the sides and bottom of the new container in three directions, namely, front-back, left-right, and up-down, to rearrange the crushed collection of crystals of the first organic compound in the new container. After this, the compressive load is applied again to the entire surface of the plate material, and the crushed collection of crystals of the first organic compound is rearranged in the new container. The crushing of the crystals of the first organic compound is further continued, and the impact acceleration in the three directions is again repeatedly applied to the side and bottom of the new container. The pair of processes consisting of the process of applying the compressive load and the process of applying the impact acceleration are repeated, and when the plate stops moving when the compressive load is applied to the plate, it is determined that the crushing of the crystals of the first organic compound is complete, and the pair of processes are stopped, and the crystals are crushed into crystals of about 20 nm in size, which is close to 1 / 5 of the size of the crystals precipitated in the container, and then the plate is removed from the new container. Then, a metal compound having both a first property of being dispersed in methanol in a molecular state but not being dissolved in methanol and a second property of precipitating a metal by thermal decomposition is dispersed in methanol to prepare a methanol dispersion of the metal compound, and then the methanol dispersion of the metal compound is heated to the boiling point of the methanol to vaporize the methanol from the methanol dispersion of the metal compound, thereby precipitating a crystal cluster of the metal compound. Then, for a second organic compound having a first property of a melting point lower than 10° C., a second property of a boiling point higher than the temperature at which the metal compound starts to thermally decompose and lower than the temperature at which the metal compound completes thermal decomposition, a third property of a viscosity of 35 mPa·sec or more at 20° C., a fourth property that crystals of the first organic compound are not dispersed or dissolved in a methanol solution obtained by dissolving the first organic compound in methanol, and a fifth property that crystals of the metal compound are not dispersed or dissolved in the methanol solution obtained by dissolving the first organic compound in methanol, the entire surfaces of all the balloons formed when the collection of crushed crystals of the first organic compound is vaporized are treated with the above-mentioned weighing out a second organic compound in an amount greater than the amount that can be covered by the mass of the second organic compound, and mixing the weighed mass of the second organic compound with methanol in an amount greater than four times the weight of the mass of the second organic compound to prepare a methanol solution of the second organic compound; and then mixing the mass of crystals of the metal compound, the weight of which is less than the weight of the weighed mass of the second organic compound, with the methanol solution of the second organic compound to prepare a first suspension in which the mass of crystals of the metal compound is dispersed in the methanol solution of the second organic compound. Further, a mass of crushed crystals of the first organic compound is mixed with the mass of the first suspension to prepare a second suspension in which the mass of crushed crystals of the first organic compound is dispersed in the first suspension. Thereafter, the second suspension is filled into a new container in the vacuum bell jar, the vacuum bell jar is sealed, and a vacuum pump is operated to reduce the pressure in the vacuum bell jar to a pressure lower than the saturated vapor pressure of the first organic compound. As a result, first, methanol is evaporated from the methanol solution of the second organic compound, the first suspension becomes a third suspension in which a cluster of crystals of the metal compound is dispersed in a cluster of the second organic compound, the third suspension covers the crushed crystals of the first organic compound, the crushed crystals of the first organic compound are evaporated, balloons made of the gas of the first organic compound are formed, the surfaces of the balloons are covered with the third suspension and the balloons are bonded together via the third suspension, a cluster of balloons in which the balloons whose surfaces are covered with the third suspension are bonded together via the third suspension is formed in a new container in the vacuum bell jar, and then the vacuum bell jar is opened to atmospheric pressure, and the cluster of balloons whose surfaces are covered with the third suspension is taken out from the vacuum bell jar. A method for producing a raw material used in producing a foam metal consisting of a collection of individual bubbles, comprising using the collection of balloons whose surfaces are covered with the third suspension as a raw material in producing a foam metal consisting of a collection of individual bubbles.

2. A method for producing a part made of foamed metal on a bottom surface of a container by using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method according to claim 1, comprising the steps of: A container having a bottom shape corresponding to a part made of foamed metal to be manufactured is filled with a part of a collection of balloons having a surface covered with the third suspension manufactured by the method described in claim 1, the container is moved to a heat treatment device, the container is exposed to an atmosphere in which the metal compound constituting the third suspension is thermally decomposed, and the temperature is raised to a temperature at which the thermal decomposition of the metal compound is completed. As a result, the container is heated, and first, thermal decomposition of the metal compound that constitutes the third suspension begins, and the metal compound decomposes into organic molecules and metal molecules, the organic molecules and the metal molecules mix with the second organic compound, and this mixed mixture covers the surface of the balloon, and as the container is heated further, the second organic compound vaporizes, and the collection of organic molecules and the collection of metal molecules cover the surface of the balloon, and as the container is heated further, vaporization accompanied by the heat of vaporization of the organic molecules begins, and the surface of the balloon is gradually covered with the collection of metal molecules, and as the container is heated further, When the evaporation of the organic molecules is complete, the metal molecules covering the surface of the balloon gather together to form metal microparticles, the collection of metal microparticles precipitates all at once on the surface of the balloon, the collection of metal microparticles stacks and metal bonds are formed at the sites where adjacent metal microparticles come into contact with each other, the collection of metal microparticles that have been metal-bonded stacks and covers the surface of the balloon, and adjacent metal microparticles covering the surface of the balloon are metal-bonded to each other, thereby bonding the balloons together via the collection of metal microparticles that have been metal-bonded, and a part consisting of a collection of balloons bonded by the collection of metal microparticles that have been metal-bonded is formed on the bottom surface of the container in the shape of the bottom surface. A method for manufacturing a part made of foamed metal on the bottom surface of a container, comprising using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method according to claim 1, and forming the part into the shape of the bottom surface of the container.

3. A method for continuously producing a sheet made of foamed metal by using as a raw material a collection of balloons the surfaces of which are covered with the third suspension produced by the method according to claim 1, comprising the steps of: Filling a container with a portion of the collection of balloons having surfaces coated with the third suspension produced by the method of claim 1; Then, for a first belt conveyor having a plane having a first feature that the width of the plane is wider than the width of the sheet of foam metal to be produced, a second feature that the plane contacts a vibration table, a third feature that vibration accelerations in three directions, namely, vertical vibrations, widthwise vibrations, and lengthwise vibrations, are alternately and continuously applied to the plane from the vibration table, and a fourth feature that the plane moves horizontally at a predetermined constant speed, the first belt conveyor is continuously operated, and further, a vibration exciter is continuously operated to apply the vibration accelerations in the three directions to the vibration table, and a predetermined amount of a collection of balloons whose surfaces are covered with the third suspension is continuously hung from the container to the front end of the plane of the first belt conveyor, the predetermined amount being the width of the sheet of foam metal to be produced. As a result, the collection of balloons whose surfaces are covered with the third suspension drips continuously onto the front end of the plane of the first belt conveyor, which corresponds to the width of the sheet of foam metal to be created, and as the plane moves horizontally at a constant speed, a coating having the width of the sheet of foam metal to be created is formed on the plane, and the vibration acceleration in the three directions is continuously and alternately applied to the coating, so that the collection of balloons covered with the third suspension that constitutes the coating are continuously rearranged within the collection of balloons so that the thickness of the coating becomes uniform, and the coating is formed into a sheet of uniform thickness, and the leading end of the sheet reaches the rear end of the plane of the first belt conveyor. Further, for a second belt conveyor having a plane that combines the first feature that the width of the plane is the same as the width of the plane of the first belt conveyor, the second feature that the plane moves horizontally at a predetermined speed, the third feature that the plane passes through a heat treatment device at the predetermined speed, which is an atmosphere in which the metal compound constituting the third suspension is thermally decomposed and which is heated to a temperature at which the thermal decomposition of the metal compound is completed, and the fourth feature that a front end of the plane is installed near a rear end of the plane of the first belt conveyor, the second belt conveyor is continuously operated in accordance with the operation of the first belt conveyor, whereby the leading end of the sheet that has reached the rear end of the plane of the first belt conveyor falls onto the front end of the plane of the second belt conveyor, and the plane of the second belt conveyor moves horizontally, so that the sheet enters the heat treatment device. When the sheet enters the heat treatment device, the temperature of the sheet rises, thermal decomposition of the metal compound constituting the third suspension begins, the metal compound decomposes into organic molecules and metal molecules, the organic molecules and the metal molecules mix with the second organic compound constituting the third suspension, and the mixed mixture covers the surface of the balloon, when the temperature of the sheet rises further, the second organic compound vaporizes, and a collection of the organic molecules and a collection of the metal molecules cover the surface of the balloon, when the temperature of the sheet rises further, vaporization accompanied by the heat of vaporization of the organic molecules begins, and the surface of the balloon is gradually covered with a collection of the metal molecules, when the temperature of the sheet rises further, the vaporization of the organic molecules is completed, the metal molecules covering the surface of the balloon gather together to form metal microparticles, the collection of metal microparticles precipitates all at once on the surface of the balloon, the collection of metal microparticles stacks and metal bonds with adjacent metal microparticles at the sites of contact, the collection of metal microparticles metallurgically stacks and covers the surface of the balloon, and adjacent metal microparticles covering the surface of the balloon metallurgically bond with each other, thereby bonding the balloons together via the collection of metal microparticles metallurgically bonded, and a sheet is formed consisting of a collection of balloons bonded with the collection of metal microparticles metallurgically bonded, and the sheet passes through the heat treatment device to continuously form a sheet consisting of a collection of balloons bonded with the collection of metal microparticles metallurgically bonded.

2. A method for continuously producing a foam metal sheet, comprising using as a raw material a collection of balloons the surfaces of which are covered with the third suspension produced by the method according to claim 1.

4. A method for producing a container or part made of foam metal in a gap of a mold by using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method according to claim 1, comprising the steps of: An outer mold and an inner mold are combined to assemble a mold, and a gap is formed between the outer mold and the inner mold. Then, a part of the group of balloons whose surfaces are covered with the third suspension produced by the method described in claim 1 is filled into the gap of the mold. The mold is then allowed to drop naturally 2-3 times onto a flat surface at a distance of 5-10 cm, and the group of balloons whose surfaces are covered with the third suspension filled in the gap of the mold is subjected to a drop impact force 2-3 times, thereby increasing the packing density of the group of balloons whose surfaces are covered with the third suspension in the gap of the mold. Thereafter, the mold is transferred to a heat treatment device, and the mold is exposed to an atmosphere in which the metal compound constituting the third suspension is thermally decomposed, and the temperature is further increased to a temperature at which the thermal decomposition of the metal compound is completed. As a result, the temperature of the mold is raised, and first, thermal decomposition of the metal compound constituting the third suspension begins, and the metal compound decomposes into organic molecules and metal molecules. The organic molecules and the metal molecules mix with the second organic compound constituting the third suspension, and this mixed mixture covers the surface of the balloon. As the temperature of the mold is further raised, the second organic compound vaporizes, and a collection of the organic molecules and a collection of the metal molecules cover the surface of the balloon. As the temperature of the mold is further raised, vaporization of the organic molecules accompanied by the heat of vaporization begins, and the surface of the balloon is gradually covered with a collection of the metal molecules. As the temperature of the mold is further raised, the vaporization of the organic molecules is completed, and the The metal molecules covering the surface of the balloon gather together to form metal microparticles, and the collection of metal microparticles precipitates all at once on the surface of the balloon, the collection of metal microparticles stacks and metal bonds with adjacent metal microparticles at the sites of contact, the collection of metal-bonded metal microparticles stacks and covers the surface of the balloon, adjacent metal microparticles covering the surface of the balloon metal-bond with each other, the balloons are bonded to each other via the collection of metal microparticles that are metal-bonded, and the collection of balloons bonded by the collection of metal-bonded metal microparticles forms a container or part in the gaps of the mold, and the size of the gaps in the mold is the wall thickness of the container or part. Thereafter, the inner mold is separated from the mold, the separated inner mold is taken out, and the container or the part is taken out from the outer mold. A method for producing a container or part made of foam metal in a gap of a mold, using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method according to claim 1.

5. The method for imparting new metallic properties to a part, sheet, container or part made of a foamed metal produced by the method according to any one of claims 2 to 4 comprises the steps of: A metal compound is produced by pyrolysis to precipitate a new metal different from the metal constituting the foamed metal part, sheet, container, or part manufactured by the method according to any one of claims 2 to 4, and the metal compound is dispersed in methanol to prepare a methanol dispersion of the metal compound. further comprising mixing an organic compound having a first property of being soluble or miscible in methanol, a second property of being more viscous than methanol, and a third property of having a boiling point higher than the boiling point of methanol and lower than the thermal decomposition temperature of the metal compound, into the methanol dispersion of the metal compound, and filling a container with the mixture in which the organic compound is dissolved or mixed into the methanol dispersion of the metal compound. Furthermore, by using each of the methods described in claims 2 to 4, a part, sheet, container or component made of foam metal is manufactured, the whole part, sheet, container or component made of foam metal is immersed in the mixed liquid in the container, the part, sheet, container or component made of foam metal is then removed from the container, the part, sheet, container or component made of foam metal is exposed to an atmosphere in which the metal compound is thermally decomposed, and the temperature is further increased to a temperature at which the metal compound is thermally decomposed. This causes a collection of metal microparticles made of the new metal to precipitate all at once on the collection of metal-bonded metal microparticles that form the surface of a part, sheet, container or component made of the metal foam, and the new metal microparticles form metal bonds at the sites where they come into contact with each other, and the metal-bonded new collection of metal microparticles covers the surface of the part, sheet, container or component made of the metal foam, thereby imparting the properties of the new metal to the part, sheet, container or component made of the metal foam.This is a method of imparting the properties of a new metal to a metal foam.

6. A method for producing a raw material used in producing a foamed metal consisting of a collection of single bubbles as described in claim 1, comprising the steps of: using the metal compound described in claim 1 as a metal octylate compound; using the first organic compound described in claim 1 as one type of monounsaturated carboxylic acid, which is one of crotonic acid, angelic acid, and tiglic acid, which belong to monounsaturated carboxylic acids; and using the second organic compound described in claim 1 as diethylene glycol, which belongs to dihydric alcohols; and using the metal compound described in claim 1 as a metal compound, the one type of monounsaturated carboxylic acid, as the first organic compound described in claim 1, and using the diethylene glycol as the second organic compound described in claim 1, and producing a raw material used in producing a foamed metal consisting of a collection of single bubbles as described in claim 1 according to the method described in claim 1.