METHOD FOR PRODUCING METAL FOAM COMPOSED OF GROUPS OF INDIVIDUAL CELLS

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 cells, in which the surface of a balloon made of a vaporized organic compound is covered with a collection of metallically bonded metal fine particles to form single cells, and adjacent metal fine particles covering the surface of the balloon are metallically bonded to each other, joining the single cells together. Prior to the present invention, the inventor has registered a patent (Japanese Patent No. 6228782) for the production of foam metal, which comprises an aggregate of void shells formed by a collection of granular fine particles of two types of metals, the void shells being joined together by metallic bonds between the granular fine particles of the second metal. In contrast, the present invention relates to a method for producing a foam metal consisting of a collection of single cells, in which the surface of a balloon made of a vaporized organic compound is covered with a collection of metallically bonded metal fine particles to form single cells, and adjacent metal fine particles covering the surface of the balloon are metallically bonded to each other, joining the single cells together. Metal foam is a cellular structure of metal, and those in which the cells are independent are called closed-cell foams, while those in which the cells are interconnected are called open-cell foams. Open-cell foams are sometimes referred to as open-cell structures, and closed-cell foams are sometimes referred to as closed-cell structures. In this invention, however, the closed-cell structure refers to the closed-cell structure. [Background technology]

[0002] Metal foams have a volume occupied by voids (also called cells or pores) that is larger than the volume occupied by the metal itself, making them lighter than conventional dense-structured metals made from ingots. Therefore, metal foams are lighter than magnesium alloys, the lightest practical metal, and can achieve weight reductions that exceed the limits of ingot-based materials. For example, the use of metal foams could enable ultra-lightweight products that surpass the use of aluminum in automobiles and magnesium in electrical products. Furthermore, due to their porous nature and large specific surface area, metal foams have the potential to be functional materials with high energy absorption, heat exchange capacity, thermal insulation, vibration damping, and sound absorption properties. They could also be used as catalyst supports and electrodes. Furthermore, if metal foams could be combined with substrates or other components, they could potentially be used in a wide range of components. As such, metal foams are a material with a wide range of potential applications that are currently being explored.

[0003] There are several methods for producing metal foams, including the casting method (also called the foam melting method or melt thickening method), which produces metal foams by casting, and the precursor method, which involves mixing a foaming agent with powdered metal such as an aluminum alloy to produce a precursor (also called a preform or metal foam precursor) and then heating it to foam. Other methods include the gas expansion method, which involves injecting argon gas into metal powder and then sintering it under pressure, which causes the gas to expand and form pores, thereby sintering the metal powder, and the continuous zone melting method, which involves absorbing nitrogen into molten metal and then pouring it into a cooled mold to solidify it in one direction. The casting method is a method in which, for example, 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 foam it (see, for example, Patent Document 1). In the precursor method, a precursor is prepared, and then the precursor is heated to decompose the foaming agent and generate gas, which causes the softened base material to expand. Various specific methods for the precursor method have been proposed, including powder metallurgy and roll bonding. In the powder metallurgy method, for example, powder of a base material such as an aluminum alloy and powder of a foaming agent are mixed until homogeneous, and the mixture is extrusion-molded. The foaming agent is then expanded by heating in an infrared furnace or the like (see, for example, Patent Documents 2 and 3). In the roll bonding method, multiple base plate materials are prepared, and after surface treatment is performed on the plates as needed, a foaming agent is sandwiched between the plates and rolled to bond the multiple plates. This rolling process is repeated until the foaming agent is uniformly dispersed in the base material, resulting in a foam metal precursor (see, for example, Patent Document 4).

[0004] However, in manufacturing methods using foaming agents such as titanium dihydride, the materials of foam metals that can be produced are limited by the thermal decomposition temperature of the foaming agent. For example, the thermal decomposition temperature of titanium dihydride (TiH2) is 470°C. The farther the melting point of the metal is from 470°C, the more the pores of the hydrogen gas generated by the thermal decomposition of titanium dihydride expand, causing the pores to combine and disappear. Therefore, when using titanium dihydride, the material is limited to aluminum, which has a melting point of 660°C, and some aluminum alloys with low melting points. On the other hand, because titanium dihydride is an expensive inorganic compound, a cheaper foaming agent, calcium carbonate (CaCO3), may be used. However, because the thermal decomposition temperature of calcium carbonate is 825°C, the foam metals are limited to metals with melting points below 1000°C. Thus, in casting methods and precursor methods using foaming agents, the types of foam metals that can be produced at the thermal decomposition temperature of the foaming agent are limited. Furthermore, in the casting process, it is difficult to uniformly disperse the foaming agent in the molten metal, making it 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, limiting 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 plate material, and the process of producing the precursor is complicated and takes a long time to produce, resulting in low productivity and expensive foam metals. Furthermore, because the roll bonding method bonds plates by rolling, it requires pretreatment such as annealing and surface treatment of the bonding surfaces, and also requires heat treatment before and after rolling, which consumes a lot of energy.Furthermore, it requires multiple rolling cycles to uniformly disperse the foaming agent, and the rolled material needs to be cut after each rolling cycle.This further reduces the productivity of metal foam and increases the production costs of metal foam. As explained above, metal foam is a developing material with a wide range of possibilities, but various problems arising from its manufacturing principles are obstacles to exploring new fields. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-61865 [Patent Document 2] DE 1048360 A1 [Patent Document 3] German Patent Application Publication No. 4101630 [Patent Document 4] Japanese Patent Application Laid-Open No. 2004-285446 Summary of the Invention [Problem to be solved by the invention]

[0006] Here, we will summarize 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. First, conventional techniques raise the temperature to melt the metal. However, the high melting point of the metal and the high heat treatment temperature cause various problems and limitations. Therefore, the first requirement for the new manufacturing method is that it can produce metal foam without melting the metal. Therefore, the new manufacturing method has a completely different metal structure that makes up the isolated foam from conventional methods. Second, conventional techniques create bubbles by thermal decomposition of a foaming agent. This limits the type of foam metal that can be produced at the thermal decomposition temperature of the foaming agent, and also creates problems with the size and distribution of the bubbles. Therefore, the second requirement for a new manufacturing method is to create pores using a new substance without using a foaming agent. Third, conventional techniques, such as the precursor method, powder metallurgy method, and roll bonding method, produce metal foams using complex and disconnected manufacturing processes. This results in high manufacturing costs and limits the applications of metal foams. Therefore, the third requirement for a new manufacturing method is that it can produce inexpensive metal foams 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 made of an aggregate of individual cells will be lighter than conventional metal foams, broadening 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 at near atmospheric pressure can be covered with a cluster of fine particles to form individual cells, and if these individual cells can be formed to be approximately 1 micron in size, the individual cells will have a certain level of mechanical strength.Furthermore, a metal foam formed from a cluster of enormous numbers of individual cells will have greater mechanical strength than conventional metal foams, thereby expanding the uses of metal foams.Therefore, the fifth requirement for the new manufacturing method is that the surface of a balloon filled with gas at near atmospheric pressure can be covered with a cluster of fine particles to form individual cells approximately 1 micron in size. Sixth, if the shape of a part made of metal foam could be freely changed, the width of a sheet made of metal foam could be freely changed, and the shape and thickness of a container or part made of metal foam could be freely changed, the applications of metal foam would be greatly expanded. Therefore, the sixth requirement for the new manufacturing method is that the shape of a part made of metal foam, the width of a sheet made of metal foam, and the shape and thickness of a container or part made of metal foam can be freely changed. Seventh, if it were possible to produce single-cell foams from a variety of metals regardless of their melting points, 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 materials that make up the single-cell foams. The problem that this invention aims to solve 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 technology. This will dramatically expand the properties of metal foam and the fields in which it can be applied. [Means for solving the problem]

[0007] single A raw material used to manufacture foam metal consisting of a collection of individual bubbles. is a group of balloons made of organic compound gas covered with a suspension in which a group of crystals of a metal compound that precipitates metal by thermal decomposition is dispersed in a group of liquid organic compounds, and the raw material The method for producing The first organic compound is It has the first property of having a melting point higher than 30°C, the second property of having a boiling point lower than the temperature at which thermal decomposition of a metal compound that precipitates metal by thermal decomposition begins, and the third property of not dissolving or dispersing the crystals in a methanol solution of a second organic compound. It is an organic compound, a first 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, a vacuum pump is operated, the pressure in the vacuum bell jar is reduced 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, and a collection of crystals of the first organic compound is precipitated in the container in the vacuum bell jar; moreover,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. The first step and , The aforementioned A collection of crystals of a first organic compound is filled into a new container, and a plate that covers the entire surface of the collection of crystals of the first organic compound is placed on top of the collection of crystals of the first organic compound. Thereafter, a compressive load is applied to the entire surface of the plate to crush the crystals of the first organic compound in the new container. Furthermore, impact accelerations are repeatedly applied to the side and bottom of the new container in three directions, i.e., front-to-back, left-to-right, and up-to-down, to rearrange the crushed collection of crystals of the first organic compound in the new container. Thereafter, the compressive load is again applied to the entire surface of the plate to further crush the crystals of the first organic compound. Furthermore, the impact accelerations in the three directions are repeatedly applied to the side and bottom of the new container again. These paired 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 it, it is determined that the crushing of the crystals of the first organic compound is complete, and the paired processes are stopped. The first organic compound The plate is crushed into crystals of about 20 nm in size, which is approximately 1 / 5 of the size of the crystal. After this, the plate is removed from the new container. The second step and , The metal compound is It disperses in methanol in a molecular state but does not dissolve in methanol, and has the second property of precipitating metals through thermal decomposition. It is a metal compound, A metal compound is dispersed in methanol to prepare a methanol dispersion of the metal compound, and then the temperature of the methanol dispersion of the metal compound is raised to the boiling point of the methanol to evaporate the methanol from the methanol dispersion of the metal compound, thereby precipitating a cluster of crystals of the metal compound. The third step and , The second organic compound isThe compound has a first property of having a melting point lower than 10°C, a second property of having 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 having a viscosity of 35 mPa·sec or more at 20°C, a fourth property of not dispersing or dissolving crystals of the first organic compound in a methanol solution obtained by dissolving the compound in methanol, and a fifth property of not dispersing or dissolving crystals of the metal compound. It is an organic compound, For a second organic compound, a collection of crushed crystals of the first organic compound. of vaporization Let formed when The first organic compound gas The entire surface of all the balloons is covered with the second organic compound by a weight greater than the weight of the second organic compound. The second organic compound The weighed mass of the second organic compound is then mixed with methanol in an amount four times greater than the weight of the mass of the second organic compound to prepare a methanol solution of the second organic compound. Thereafter, the mass of crystals of the metal compound, the amount of which is less than the weight of the weighed mass of the second organic compound, is mixed 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. The fourth step , The aforementioned mixing a collection of crushed crystals of said first organic compound with the collection of first suspension; Applicable A second suspension is prepared in which aggregates of crushed crystals of the first organic compound are dispersed in the first suspension. The fifth step , The aforementioned The second suspension is The aforementioned Fill a new container in a vacuum bell jar, moreover, The vacuum bell jar is sealed and the vacuum pump is operated; Applicable reducing the pressure inside the vacuum bell jar to a pressure lower than the saturated vapor pressure of the first organic compound; This means thatFirst, methanol evaporates from the methanol solution of the second organic compound, and the first suspension becomes a third suspension in which clusters of crystals of the metal compound are dispersed in clusters of the second organic compound, and the third suspension covers the crushed crystals of the first organic compound. Next, the crushed crystals of the first organic compound evaporate, and balloons made of 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. Then, the balloons whose surfaces are covered with the third suspension are bonded together via the third suspension. Applicable A collection of balloons is formed in a new container within the vacuum bell jar. R and then releasing the vacuum bell jar to atmospheric pressure and removing the collection of balloons whose surfaces are covered with the third suspension from the vacuum bell jar. The sixth step is , By continuously carrying out all of the treatments consisting of these six steps, the balloons made of the gas of the first organic compound are covered with a suspension in which a collection of crystals of a metal compound that precipitates a metal by thermal decomposition is dispersed in the collection of the second organic compound, and a collection of balloons in which the balloons are bonded together with the suspension is produced, and the collection of balloons in which the balloons are covered with the suspension and bonded together with the suspension is Used as a raw material for producing foam metal consisting of a collection of individual bubbles. Characterized by A method for producing a raw material used in producing 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. Thereafter, the methanol solution of the first organic compound is 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 inside the vacuum bell jar to a pressure lower than the saturated vapor pressure of methanol, vaporizing the methanol from the methanol solution of the first organic compound and precipitating a cluster of crystals of the first organic compound in the container inside the vacuum bell jar. In other words, since the first organic compound forms a single-cell 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 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 microparticles 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. To this end, the first organic compound is dissolved in methanol, the methanol solution of the first organic compound is filled into a container inside a vacuum bell jar, the vacuum bell jar is sealed, a vacuum pump is operated, the pressure inside the vacuum bell jar is reduced to a pressure lower than the saturated vapor pressure of methanol, and the methanol is evaporated from the methanol solution of the first organic compound, resulting in a cluster of crystals of the first organic compound being precipitated in the container inside 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 by heating the methanol solution of the first organic compound to the boiling point of methanol and evaporating the methanol. However, the boiling points of all first organic compounds are not higher than 65°C. To this end, a methanol solution of the first organic compound was filled into a container inside a vacuum bell jar, and the pressure inside the vacuum bell jar was reduced to a pressure lower than the saturated vapor pressure of methanol, vaporizing the methanol from the methanol solution of the first organic compound and precipitating a cluster of crystals of the first organic compound with a melting point higher than 30°C. These crystals are a cluster 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, applying stress to the crystals causes them to break down into finer crystals. On the other hand, the finer the crystals, the more difficult it becomes to apply stress to them, and there is a limit to how fine the crystals can be made. Second, the crystals of the first organic compound are crushed to about one-fifth their original size. That is, by attaching a raw material that will become a cluster of metal particles to the surface of the crystals of the first organic compound and then vaporizing the crystals of the first organic compound, a balloon covered with the raw material that will become a cluster of metal particles can be formed. Meanwhile, when the crystals of the first organic compound are vaporized, they become a gas of the first organic compound with a volume equal to the molar ratio of the crystals of the first organic compound multiplied by 22.4 liters. Therefore, the larger the molar ratio of the crystals of the first organic compound, i.e., 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 vaporized crystals of the first organic compound with a diameter of 100 nm is 125 times the volume of vaporized crystals of the first organic compound with a diameter of 20 nm. Furthermore, 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 crystals of the first organic compound are spherical, when a spherical crystal of the first organic compound with a diameter of 20 nm vaporizes, 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 vaporizes, it becomes difficult to cover the balloon of the gas of the first organic compound with a raw material that will become a collection of metal microparticles. For this reason, the crystals of the first organic compound were crushed to about 1 / 5 of their original size using the following process. First, a collection of crystals of a first organic compound is filled into a container, and a plate is placed over the collection of crystals of the first organic compound in the container to constrain the collection of crystals of the first organic compound within the container. The collection of crystals of the first organic compound is then compressed via the plate. During this process, the larger the crystal size, the more easily it is crushed. Therefore, the relatively larger crystals are crushed first, and the crushing of the crystals progresses while the compressive load is applied. Meanwhile, in the collection of crystals within the container, new voids are formed as the crystals are crushed, and the crystals move to fill the voids while the compressive load is applied. After this, the applied compressive load is stopped, and impact acceleration is repeatedly applied to the container in three directions: front-to-back, left-to-right, and up-to-down. During this process, the crystals do not scatter because they are constrained within the container by the plate. Instead, 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 crushed collection of crystals via the plate. During this process, the crushed crystals continue to break down into smaller clusters of crystals. After this, the container is again subjected to repeated impact acceleration in three directions, further realigning the clusters of finer crystals. This pair of processes, consisting of applying a compressive load and applying an impact acceleration in three directions, is repeated. However, as the crystals become finer, it becomes more difficult to apply compressive stress to the crystals even when a compressive load is applied, and there is a limit to how much the crystals can be refined. When the limit of crystal refinement is reached, applying a compressive load to the plate material no longer advances the crushing of the crystals, 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, nearly one-fifth of the size at the time of precipitation. Since the crushed crystals of the first organic compound are vaporized to form fine balloons, the weight of the clusters of crushed crystals of the first organic compound is small. Therefore, the compressive load applied to the plate material is equivalent to 3-5 kg, depending on the size of the container. The impact acceleration applied to the container is 0.2-0.3G depending on the size of the container. Third, a cluster of crystals of the metal compound is precipitated. To this end, the metal compound is dispersed in methanol, and then the methanol dispersion of the metal compound is heated to the boiling point of methanol, evaporating the methanol and precipitating a cluster of crystals of the metal compound. In other words, when a metal compound that precipitates metals by thermal decomposition is dispersed in methanol, the most commonly used organic solvent, the metal compound becomes molecular and disperses in the methanol. In contrast, when a metal compound dissolves in methanol, the metals that make up the metal compound become metal ions and are eluted into the methanol, and the dissolved metal compound cannot return to the metal compound before dissolution. Therefore, even if methanol is evaporated from a methanol solution of the metal compound, crystals of the metal compound before dissolution do not precipitate. Therefore, a metal compound that does not dissolve in methanol and disperses in methanol is used as a metal compound that precipitates metals by thermal decomposition. As a result, when methanol is evaporated from a methanol dispersion of the metal compound, the metal compound precipitates as metal compound crystals smaller than 100 nm. These crystals are a collection of crystals formed by the accumulation of single molecules of metal compounds, which are formed when metal compounds dispersed in methanol in a molecular state are precipitated. The vaporized methanol is recovered and reused. Fourth, a cluster of the second organic compound is dissolved in methanol to prepare a first suspension in which a cluster of crystals of the metal compound is dispersed in the methanol solution. This suspension is a raw material for forming clusters of metal particles that adhere to the surfaces 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 thermal decomposition of the metal compound begins and lower than the temperature at which thermal decomposition of the metal compound is completed, a viscosity of 35 mPa·s or higher at 20°C, and the crystals of the first organic compound do not disperse or dissolve in the methanol solution in which the second organic compound is dissolved. Specifically, in the sixth process, a second suspension in which clusters of crushed crystals of a first organic compound are dispersed in a first suspension is filled into a container in a vacuum bell jar, a vacuum pump is operated, and the pressure inside the vacuum bell jar is reduced to a pressure lower than the saturated vapor pressure of the first organic compound. The methanol is evaporated from the first suspension, converting the first suspension into a third suspension in which clusters of crystals of a metal compound are dispersed in the second organic compound. The crushed crystals of the first organic compound are then evaporated to form a balloon of the first organic compound gas, which is then covered with the third suspension in which the methanol is evaporated from the first suspension. The second organic compound has a melting point lower than 10°C and is liquid at room temperature. Furthermore, because the boiling point of the second organic compound is higher than that of the first organic compound, the second organic compound remains in the third suspension when the crystals of the first organic compound evaporate. Furthermore, 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 evaporates from the first suspension covering the surface of the crushed crystals of the first organic compound, and a third suspension in which clusters of metal compound crystals are dispersed in the second organic compound covers the surface of the balloon. Therefore, the viscosity of the second organic compound is high, at 20°C, of ​​35 mPa·sec or more. 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 covering the surface of the crushed crystals of the first organic compound deforms significantly. However, because the viscosity of the third suspension is high and it covers the surface of the crushed crystals of the first organic compound to a certain thickness, the third suspension deforms and covers the balloon. Furthermore, the balloons are bonded together via the third suspension covering the surface of the balloon. As a result, a cluster of balloons covered with the third suspension is created, with the balloons covered with the third suspension bonded together via the third suspension. Furthermore, because the first suspension is composed of a methanol dilution of the second organic compound and a collection of metal compound crystals, the second organic compound does not disperse or dissolve the metal compound crystals. 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 nearly 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 weight of both the second organic compound and the metal compound is 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, a second organic compound is weighed out at a weight greater than the weight required to cover the surface of all balloons formed when the crushed crystal clusters of the first organic compound are vaporized. This results in the surface of the balloons being covered with a certain thickness of the third suspension. Next, the weighed second organic compound cluster is mixed with methanol in an amount 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 metal compound crystal cluster, weighing less than the weighed second organic compound cluster, is mixed with the methanol solution of the second organic compound to prepare a first suspension in which the metal compound crystal clusters are dispersed in the methanol solution of the second organic compound. Fifth, a mass of crushed crystals of the first organic compound is mixed with the mass of the first suspension to produce a second suspension in which the mass of crushed crystals of the first organic compound is dispersed. The mass of crushed crystals of the first organic compound does not dissolve or disperse in the methanol solution of the second organic compound. In other words, in the sixth process, the crystals of the first organic compound are vaporized to form a balloon of the first organic compound gas. The entire surface of the balloon is then covered with the third suspension, resulting in a mass of crushed crystals of the first organic compound that constitutes the second suspension being significantly less than the mass of the second organic compound that constitutes the first suspension. This vaporizes the crystals of the first organic compound, allowing the surface of a balloon with a volume equal to the molar ratio of the crystals of the first organic compound multiplied by 22.4 liters to be covered with the third suspension. Sixth, the second suspension is filled into a container in a vacuum bell jar, and the vacuum pump is operated to reduce the pressure inside the vacuum bell jar to a pressure lower than the saturated vapor pressure of the first organic compound. This vaporizes the methanol from the methanol solution of the second organic compound, followed by vaporization of the crushed crystals of the first organic compound. That is, as the methanol evaporates from the methanol solution of the second organic compound, the first suspension becomes a third suspension in which 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 vaporize, forming balloons of the first organic compound gas in an equilibrium state. The third suspension covers the surfaces of the equilibrium balloons, and a collection of balloons covered with the third suspension is formed in the container in the vacuum bell jar. Furthermore, the balloons are bonded to each other via the third suspension covering the surfaces of the balloons. In other words, when the crushed crystals of the first organic compound vaporize and form a balloon of gaseous first organic compound, the third suspension covering the surface of the crushed crystals of the first organic compound undergoes significant deformation. However, because the viscosity of the third suspension is high (35 mPa·sec or more at 20°C) and it covers the crushed crystals of the first organic compound to a certain thickness, the third suspension covers the surface of the balloon. The balloon covered with the third suspension is an irreversible change, so the balloon will not return to crystals of the first organic compound. When crushed first organic compound particles, each approximately 20 nm in size, vaporize, a balloon with a radius of approximately 650 nm is formed. The vaporized methanol is recovered and reused. All six of the processes described above are simple. Furthermore, the raw materials used—methanol, organic compounds, and metal compounds—are common industrial chemicals. Therefore, by using inexpensive raw materials and carrying out the six simple processes in succession, the raw materials used to manufacture metal foam can be produced inexpensively.

[0009] A method for manufacturing a part made of foam metal on a bottom surface of a container using a collection of balloons whose surfaces are covered with the third suspension produced by the method described in paragraph 7 as a raw material, the method comprising: a container having a bottom surface that corresponds to the shape of the foam metal part to be manufactured, filled with a portion of the collection of balloons whose surfaces are covered with the third suspension produced by the method described in paragraph 7; the container is transferred to a heat treatment device, where 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 temperature of the container is raised, and first, thermal decomposition of the metal compound that makes up the third suspension begins, the metal compound decomposing into organic molecules and metal molecules, the organic molecules and the metal molecules mixing in the second organic compound, and this mixed mixture covering the surface of the balloon, when the temperature of the container is further raised, the second organic compound vaporizes, and a collection of the organic molecules and a collection of the metal molecules covers the surface of the balloon, when the temperature of the container is further raised, the organic molecules starting to vaporize with the heat of vaporization, and the surface of the balloon is gradually covered with a collection of the metal molecules, when the temperature of the container is further raised, 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 up, and adjacent metal microparticles form metallic bonds at the contact points, the collection of metal microparticles that have formed metallic bonds stacks up to cover the surface of the balloon, and adjacent metal microparticles that have covered the surface of the balloon form metallic bonds, so that the balloons are joined together via the collection of metal microparticles that have formed metallic bonds, and a part consisting of the collection of balloons joined by the collection of metal microparticles that have formed metallic bonds is formed on the bottom surface of the container in the shape of the bottom surface. By continuously carrying out all of the above-mentioned processes, a part made of foam metal is manufactured on the bottom surface of the container in the shape of the bottom surface. A method for producing a part made of foam metal in the shape of the bottom surface of a container using as 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 foam metal part to be manufactured, the container is exposed to an atmosphere in which the metal compound constituting the third suspension will thermally decompose, and the temperature is then raised to a temperature at which the thermal decomposition of the metal compound is completed, and a foam metal part is manufactured on the bottom surface of the container in the shape of the bottom surface. That is, when the temperature of the container is raised, the group of balloons covered with the third suspension also rises in temperature, 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 begins 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 begins, the metal compound decomposes into organic molecules and metal molecules, and the organic molecules and metal molecules mix with the second organic compound, and this 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 absorb the heat of vaporization and begin to vaporize, 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 microparticles, and a group of metal microparticles approximately 50 nm in size precipitates all at once on the surface of the balloon, forming a layer of metal microparticles. The clusters of metal microparticles are metallically bonded at the contact points between adjacent metal microparticles. Furthermore, as adjacent metal microparticles covering the surface of the balloons are metallically bonded to each other, the balloons are joined together via the clusters of metallically bonded metal microparticles, 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, let's assume that seven layers of metal-bonded metal microparticles each about 50 nm in size are stacked to cover the surface of a balloon. Furthermore, each stacked metal microparticle is metal-bonded to six adjacent metal microparticles in the same layer, and to five or six adjacent metal microparticles in the layers above and below. Therefore, the metal microparticles stacked together by the metal-bonded metal microparticles are airtight against the gas that forms the balloon, and the gas in the balloon is contained inside the balloon. As a result, the balloon covered with the metal-bonded metal microparticles, i.e., the single bubble, will be about 1 micron in size. That is, when a crushed first organic compound about 20 nm in size is vaporized, a balloon with a radius of about 650 nm is formed. Furthermore, if seven layers of metal microparticles each about 50 nm in size are stacked on the surface of the balloon, the metal microparticles will be about 350 nm thick. 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 seven layers of metal microparticles with a size of about 50 nm are layered on the surface of a balloon with a radius of about 650 nm to form a single-cell bubble, the weight of the metal sphere with a radius of 1000 nm will be reduced by 65%. Therefore, the weight reduction effect of foam metals consisting of a collection of single-cell bubbles is significant. The part made of foam metal manufactured by the method described above provides the following effects. First, since the part made of foam 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 foam metal. Second, because the temperature at which the thermal decomposition of the metal compound is completed is 290°C, the temperature at which 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. Third, since the balloons are formed by vaporizing the powder of an organic compound, there are no restrictions on the use of foaming agents that are required in the conventional production of foam metals. Fourth, the internal pressure of the single-cell foam is close to atmospheric pressure and not negative. Furthermore, because the vast number of single-cell foams are bonded together by a collection of metal particles formed by stacking metal particles with metallic bonds, parts made of metal foam have a certain level of mechanical strength based on the metallic bonding strength of the stacked metal particles. In other words, because the organic compounds coated with a viscous suspension vaporize and form balloons while covered with the suspension, the balloons have a pressure close to atmospheric pressure and are not under negative pressure. Furthermore, because the balloons, which are at near-atmospheric pressure, are bonded together by a collection of metal particles formed by stacking metal particles with metallic bonds, parts made of metal foam have a certain level of mechanical strength based on the metallic bonding strength of the metal particles. In other words, a collection of stacked metal particles metallically bonds with six adjacent metal particles in the same layer, and with five to six adjacent metal particles in the layers above and below. Therefore, parts made of metal foam have a certain level of mechanical strength. Fifth, parts made of metal foam are lighter than parts made of conventional metal foam. That is, as described above, if the crushed first organic compound, which is about 20 nm in size, vaporizes to form a balloon, and a collection of metal microparticles, each about 50 nm in size, is layered on the surface of this balloon to form a single bubble, the weight of the balloon will be nearly 65% ​​lighter than if a sphere with a radius of 1 μm were formed from a bulk metal material. Therefore, parts made of metal foam 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 up of countless submicron-sized balloons of sealed gas that are bonded together, 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 microparticles through thermal decomposition precipitate metal microparticles of various materials, so parts made of metal foam can freely change the metal that makes up the metal microparticles depending on the part's use. In the present invention, the foam metal parts are manufactured by forming balloons by vaporizing an organic compound without using a foaming agent. Furthermore, the foam metal parts are manufactured using a collection of balloons whose surfaces are covered with the third suspension described in paragraph 7 as raw material, so that the foam metal parts can be manufactured inexpensively using a manufacturing method that involves a series of simple processes. As a result, all seven issues listed in paragraph 6 were resolved.

[0011] A method for continuously producing a sheet of foam 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: Filling a container with a portion of the collection of balloons coated with the third suspension prepared by the method described in paragraph 7; Thereafter, for a first belt conveyor having a plane that has a first feature in which the width of the plane is wider than the width of the sheet of foam metal to be produced, a second feature in which the plane is in contact with a vibration table, a third feature in which three-directional vibrations consisting of vertical vibrations, widthwise vibrations, and lengthwise vibrations are alternately and continuously applied to the plane from the vibration table, and a fourth feature in which 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 dropped from the container onto 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, a group of balloons whose surfaces are covered with the third suspension drips continuously onto the front end of the plane of the first belt conveyor, the width of 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 group of balloons covered with the third suspension that constitutes the coating are continuously rearranged within the group of balloons to make the thickness of the coating 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. Furthermore, 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, 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 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 further, 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 that constitutes 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 that constitutes the third suspension, and this mixed mixture covers the surface of the balloon. As the temperature of the sheet further rises, the second organic compound vaporizes, and a group of the organic molecules and a group of the metal molecules cover the surface of the balloon. As the temperature of the sheet further rises, vaporization of the organic molecules begins, accompanied by the heat of vaporization, and the surface of the balloon is gradually covered with a group of the metal molecules. As the temperature of the sheet further rises, 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 up and metal bonds between adjacent metal microparticles at the contact points, the collection of metal microparticles that have metal bonds stacks up to cover the surface of the balloon and the adjacent metal microparticles that have covered the surface of the balloon metal bond together, thereby bonding the balloons together via the collection of metal microparticles that have metal bonds, and a sheet is formed consisting of a collection of balloons bonded together by the collection of metal microparticles that have metal bonds, and the sheet passes through the heat treatment device to continuously form a sheet consisting of a collection of balloons bonded together by the collection of metal microparticles that have metal bonds. By continuously carrying out all of the above-mentioned processes, a sheet made of foam metal is continuously produced. A method for continuously producing a sheet of foam metal using as 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 continuously operated, and further, the vibrator is continuously operated to apply vibrations in three directions to the vibration table and 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 portion of the collection of balloons covered with the third suspension to the front end of the plane of the horizontally moving first belt conveyor, over the width of the sheet to be formed, and the plane of the first belt conveyor is moved horizontally, so that a film-like sheet is formed on the plane of the first belt conveyor. In addition, vibrations are continuously and alternately applied to the coating in three directions, and the group of balloons covered with the third suspension that constitutes the coating are repeatedly rearranged within the group of balloons to make the thickness of the coating 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 the container described in paragraph 10, when the collection of balloons covered with the third suspension passes through the heat treatment device, the collection of balloons covered with the third suspension rises 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 begins 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 begins, the metal compound decomposes into organic molecules and metal molecules, and the organic molecules and metal molecules mix with the second organic compound, and this mixture covers the surface of the balloon. After this, the second organic compound vaporizes, and a cluster of organic molecules and a cluster of metal molecules cover the surface of the balloon. Furthermore, as the organic molecules absorb the heat of vaporization and begin to vaporize, a cluster of metal molecules gradually covers the surface of the balloon. Furthermore, when the vaporization of the organic molecules is complete, the metal molecules gather to form metal microparticles, and a cluster of metal microparticles with a size of approximately 50 nm precipitates simultaneously on the surface of the balloon, forming a layer of metal microparticles. The clusters of metal microparticles form metallic bonds at the sites where adjacent metal microparticles 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 clusters of metallically bonded metal microparticles, and the sheet consisting of the cluster of balloons is passed through a heat treatment device, whereby the sheet is continuously formed. Here, let's assume that seven layers of metal-bonded metal microparticles each about 50 nm in size are stacked to cover the surface of a balloon. Furthermore, each stacked metal microparticle is metal-bonded to six adjacent metal microparticles in the same layer, and to five or six adjacent metal microparticles in the layers above and below. Therefore, the metal microparticles stacked together by the metal-bonded metal microparticles are airtight against the gas that forms the balloon, and the gas in the balloon is contained inside the balloon. As a result, the balloon covered with the metal-bonded metal microparticles, i.e., the single bubble, will be about 1 micron in size. That is, when a crushed first organic compound about 20 nm in size is vaporized, a balloon with a radius of about 650 nm is formed. Furthermore, if seven layers of metal microparticles each about 50 nm in size are stacked on the surface of the balloon, the metal microparticles will be about 350 nm thick. 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 seven layers of metal microparticles with a size of about 50 nm are layered on the surface of a balloon with a radius of about 650 nm to form a single-cell bubble, the weight of the metal sphere with a radius of 1000 nm will be reduced by 65%. Therefore, the weight reduction effect of foam metals consisting of a collection of single-cell bubbles is significant. The foam metal sheet manufactured by the method described above provides the same seven functional effects as the foam metal part described in paragraph 10. Furthermore, the foam metal sheet of the present invention solves all of the seven problems described in paragraph 6, as does 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 using a collection of balloons whose surfaces are covered with the third suspension produced by the method described in paragraph 7 as a raw material, comprising: 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 portion of the group of balloons whose surfaces are coated with the third suspension produced by the method described in paragraph 7 is filled into the gap in the mold. The mold is then dropped 2-3 times onto a flat surface at a distance of 5-10 cm, and the group of balloons whose surfaces are coated with the third suspension filled in the gap in 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 coated 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 rises, 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 that constitutes the third suspension, and this mixed mixture covers the surface of the balloon. As the temperature of the mold further rises, the second organic compound vaporizes, and a group of the organic molecules and a group of the metal molecules cover the surface of the balloon. As the temperature of the mold further rises, vaporization of the organic molecules begins, accompanied by the heat of vaporization, and the surface of the balloon is gradually covered with a group of the metal molecules. As the temperature of the mold further rises, 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, the collection of metal microparticles precipitates all at once on the surface of the balloon, the collection of metal microparticles stacks up and metal bonds between adjacent metal microparticles at the contact points, the collection of metal-bonded metal microparticles stacks up and covers the surface of the balloon, adjacent metal microparticles covering the surface of the balloon metal-bond together, the balloons are joined together via the collection of metal-bonded metal microparticles, and the collection of balloons joined by the collection of metal-bonded metal microparticles forms a container or part shape that is the shape of the gap in the mold, and the size of the gap in the mold is the wall thickness of the container or part, and the container or part is formed in the gap in the mold. 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. By carrying out all of the above-mentioned processes in succession, a container or part made of foam metal is produced in the gap between the molds. 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] Specifically, a portion of the group of balloons coated with the third suspension produced by the method described in paragraph 7 is filled into the mold gap formed between an outer mold and an inner mold. The mold is then subjected to two or three drop impacts to increase the packing density of the group of balloons coated with the third suspension in the mold gap. The mold is then transferred to a heat treatment device, exposed to an atmosphere in which the metal compound constituting the third suspension thermally decomposes, and heated to a temperature at which the thermal decomposition of the metal compound is completed. This results in the formation of a metal foam container or part in the mold gap, with a shape and wall thickness determined by the shape of the mold gap. For example, a cylindrical container, a rectangular container, or a cylindrical or rectangular part can be formed. The wall thickness of the container or part is determined by the shape of the mold gap. That is, the gap between the molds is filled with a group 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 thermally decompose, and the temperature is raised to a temperature at which the thermal decomposition of the metal compounds is completed. During this process, the group of balloons covered with the third suspension filled in the gap between the molds is heated, as in the case of manufacturing a part in the shape of the bottom of a container 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 begins 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 begins, the metal compound decomposes into organic molecules and metal molecules, and the organic molecules and metal molecules mix with the second organic compound, and this mixture covers the surface of the balloon. After this, the second organic compound vaporizes, and a cluster of organic molecules and a cluster of metal molecules cover the surface of the balloon. Furthermore, as the organic molecules absorb the heat of vaporization and begin to vaporize, a cluster of metal molecules gradually covers the surface of the balloon. Furthermore, when the vaporization of the organic molecules is complete, the metal molecules gather to form metal microparticles, and a cluster of metal microparticles with a size of approximately 50 nm precipitates simultaneously on the surface of the balloon, forming a layer of metal microparticles. The clusters of metal microparticles form metallic bonds at the sites where adjacent metal microparticles contact each other. Furthermore, adjacent metal particles covering the surface of the balloons are metallically bonded to each other, so that the balloons are joined together via the clusters of metallically bonded metal particles, and a container or part consisting of the cluster of balloons is formed in the gap between the molds, with the shape of the container or part being the same as the gap between the molds and the size of the gap between the molds 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 cluster of balloons is removed from the separated mold. Here, let's assume that seven layers of metal-bonded metal microparticles each about 50 nm in size are stacked to cover the surface of a balloon. Furthermore, each stacked metal microparticle is metal-bonded to six adjacent metal microparticles in the same layer, and to five or six adjacent metal microparticles in the layers above and below. Therefore, the metal microparticles stacked together by the metal-bonded metal microparticles are airtight against the gas that forms the balloon, and the gas in the balloon is contained inside the balloon. As a result, the balloon covered with the metal-bonded metal microparticles, i.e., the single bubble, will be about 1 micron in size. That is, when a crushed first organic compound about 20 nm in size is vaporized, a balloon with a radius of about 650 nm is formed. Furthermore, if seven layers of metal microparticles each about 50 nm in size are stacked on the surface of the balloon, the metal microparticles will be about 350 nm thick. 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 seven layers of metal microparticles with a size of about 50 nm are layered on the surface of a balloon with a radius of about 650 nm to form a single-cell bubble, the weight of the metal sphere with a radius of 1000 nm will be reduced by 65%. Therefore, the weight reduction effect of foam metals consisting of a collection of single-cell bubbles is significant. A container or part made of a metal foam produced by the method described above provides the same seven functional effects as the part made of a metal foam described in paragraph 10. Furthermore, a container or part made of a metal foam according to the present invention solves all of the seven problems described in paragraph 6, as does the part made of a metal foam described in paragraph 10.

[0015] 9th paragraph, 11th paragraph, and, The method for imparting new metallic properties to a part, sheet, container or component made of a metal foam produced by each of the methods described in paragraph 13 is as follows: 9th paragraph, 11th paragraph, and,A metal compound is produced by pyrolysis to precipitate a new metal different in material from the metal constituting the part, sheet, container, or part made of foam metal produced by the method described in paragraph 13, and the metal compound is dispersed in methanol to prepare a methanol dispersion of the metal compound. moreover, Organic compounds are The first property is that it dissolves or is miscible in methanol, the second property is that it has a higher viscosity than methanol, and the boiling point is higher than the boiling point of methanol, and New metals are precipitated by thermal decomposition Organic compounds with a third property that are lower than the thermal decomposition temperature of metal compounds and the organic compound of before Note New metals are precipitated by thermal decomposition mixing the organic compound with a methanol dispersion of a metal compound, and filling a mixture of the organic compound dissolved or mixed in the methanol dispersion of the metal compound into a container; Furthermore, paragraphs 9 and 11, and, A part, sheet, container or component made of foam metal is manufactured by each of the methods described in paragraph 13, and the part, sheet, container or component made of foam metal is immersed entirely in the mixed liquid in the container, and then the part, sheet, container or component made of foam metal is removed from the container, and the part, sheet, container or component made of foam metal is immersed in the mixed liquid in the container, and New metals are precipitated by thermal decomposition The metal compound is exposed to an atmosphere in which the metal compound is thermally decomposed, and New metals are precipitated by thermal decomposition The temperature rises to the point where the metal compound thermally decomposes. As a result, clusters of metal particles made of the new metal are precipitated all at once on the clusters of metal-bonded metal particles that form the surface of the part, sheet, container or component made of the foam metal, and the new metal particles are metal-bonded at the points where they come into contact with each other, and the metal-bonded new clusters of metal particles cover the surface of the part, sheet, container or component made of the foam metal, thereby imparting the properties of the new metal to the part, sheet, container or component made of the foam metal. 9th paragraph, 11th paragraph, and, 13 paragraphs A part, a sheet, a container or a component made of foam metal produced by each of the methods described in 1. A method for imparting new metallic properties to metal foam.

[0016] That is, paragraph 9, paragraph 11, and,By manufacturing a part, sheet, container or component made of foam metal using each of the methods described in paragraph 13, and covering the surface of the part, sheet, container or component made of foam metal with a collection of metal-bonded metal microparticles made of a new metal that is different in material from the metal that makes up the part, sheet, container or component made of foam metal, the part, sheet, container or component made of foam metal will be given the properties of the new metal. That is, a metal compound that precipitates by thermal decomposition a new metal different from the metal that constitutes the foam metal part, sheet, container, or part is dispersed in methanol to prepare a methanol dispersion of the metal compound. An organic compound that combines the three properties is mixed into this methanol dispersion of the metal compound. After this, in paragraphs 9 and 11, and, A metal foam part, sheet, container, or component manufactured by the method described in paragraph 13 is immersed in a liquid mixture, and then the metal foam part, sheet, container, or component is removed from the liquid mixture. The metal foam part, sheet, container, or component is then exposed to an atmosphere in which the metal compound thermally decomposes, and heated to a temperature at which the metal compound thermally decomposes. This causes clusters of metal particles made of a new metal to simultaneously precipitate on the clusters of metal-bonded metal particles that form the surface of the metal foam part, sheet, container, or component. The new metal particles form metal bonds with each other where they come into contact, and the metal-bonded clusters of new metal particles cover the surface of the metal foam part, sheet, container, or component, thereby imparting the properties of the new metal to the metal foam part, sheet, container, or component. For example, paragraph 9, paragraph 11, and,By using the method described in paragraph 13 to produce a part, sheet, container, or component made of a metal foam consisting of an aggregate of aluminum fine particles, and then covering the surface of the part, sheet, container, or component made of the metal foam with an aggregate of metallically bonded silver fine particles, the properties of silver can be imparted to the metal foam. In this case, by using a reduced amount of a silver compound that precipitates silver by thermal decomposition, the surface of the part, sheet, container, or component made of a metal foam consisting of an aggregate of aluminum fine particles is thinly layered, for example, two layers of silver fine particles are precipitated, and the aggregate of metallically bonded silver fine particles covers the metal foam, the properties of silver, for example, the catalytic action of silver, can be imparted to the metal foam by using a smaller amount of silver compound than the aluminum compound that forms the metal foam. Also, paragraphs 9 and 11, and, By using the methods described in paragraph 13 to produce a part, sheet, container, or component made of a metal foam consisting of an aggregate of aluminum fine particles, and then covering the surface of the metal foam with an aggregate of metallically bonded nickel fine particles, ferromagnetic properties can be imparted to the non-magnetic metal foam consisting of an aggregate of aluminum fine particles. In this case, by using a reduced amount of nickel compound that precipitates nickel by thermal decomposition, and by slightly layering the surface of the metal foam consisting of an aggregate of aluminum fine particles, for example, by forming two layers of nickel fine particles and covering the surface of the metal foam with an aggregate of metallically bonded nickel fine particles, ferromagnetic properties can be imparted to the metal foam using a smaller amount of nickel compound than the aluminum compound that forms the metal foam.

[0017] In paragraph 7 The method for producing a raw material used in producing the foam metal consisting of a collection of single cells described above includes the steps of: The metal compound described in paragraph 7 is an octylic acid metal compound, the first organic compound described in paragraph 7 is one of crotonic acid, angelic acid, and tiglic acid, which belong to the monounsaturated carboxylic acids, and the second organic compound described in paragraph 7 is diethylene glycol, which belongs to the dihydric alcohol, and the octylic acid metal compound is used as the metal compound described in paragraph 7, and EitherA raw material for producing a foam metal consisting of a collection of single cells is produced according to the method of paragraph 7, using one monounsaturated carboxylic acid as the first organic compound described in paragraph 7 and the diethylene glycol as the second organic compound described in paragraph 7. A method for producing a raw material used in producing a metal foam consisting of a collection of single cells as described in paragraph 7.

[0018] In other words, when metal octylate compounds are heat-treated at 290°C in an air atmosphere, they precipitate a metal. Furthermore, they disperse in methanol at nearly 10% by weight and are insoluble in methanol. Therefore, metal octylate compounds can be used as metal compounds that combine the two properties described in paragraph 7. Furthermore, when metal octylate compounds exceed 228°C, the boiling point of octylate, the bond between the oxygen ion and the metal ion that constitutes the carboxyl group is first broken, separating into octylate and the metal. Furthermore, because octylate is a saturated fatty acid, it does not have an unsaturated structure in which carbon atoms are in excess of hydrogen atoms. Therefore, octylate absorbs the heat of vaporization and vaporizes, and the metal precipitates at 290°C, when vaporization is complete. Therefore, metal octylate compounds are heat-treated in an air atmosphere. In contrast, the monounsaturated carboxylic acids crotonic acid CH3(CH)2COOH, angelic acid CH3CH:C(CH3)COOH, and tiglic acid CH3CH:C(CH3)COOH possess the first property of a melting point higher than 30°C and the second property of a boiling point lower than 228°C, the temperature at which thermal decomposition of octylic acid compounds begins, which deposit metals. Specifically, 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 monounsaturated carboxylic acids possess both a melting point higher than 30°C and a boiling point lower than the temperature at which thermal decomposition of metal octylic acid compounds begins, which deposit metals. Therefore, these three monounsaturated carboxylic acids can be used as the first organic compound described in paragraph 7. Furthermore, diethylene glycol (CH2CH2OH)2O, a dihydric alcohol, has a melting point of -10°C, a boiling point of 244°C, and a viscosity of 36 mPa·s at 20°C. Crystals of metal octylate compounds do not disperse or dissolve in diethylene glycol. Therefore, diethylene glycol can be used as a second organic compound that combines the four properties described in paragraph 7: 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 complete), a viscosity of 35 mPa·s or higher at 20°C, and crystals of metal octylate compounds do not disperse or dissolve. The crystals of the three monounsaturated carboxylic acids described above have the property of neither dissolving nor dispersing in a diethylene glycol methanol solution. Therefore, when a first suspension in which a cluster of crystals of a metal octylate compound is dispersed in a diethylene glycol methanol solution is mixed with a cluster of crushed crystals of the three monounsaturated carboxylic acids, a second suspension is produced. When this 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 inside the vacuum bell jar. This results in the production of a raw material used to produce foam metals consisting of a cluster of single-cell bubbles. Next, we will explain the properties of the above-mentioned metal octylate compound. As described in paragraph 7, the crystal size of the metal compound is less than 100 nm. When such crystals of a metal octylate compound are thermally decomposed, they separate into octylic acid and the metal. After the octylic acid evaporates, metal nanoparticles with a size of about 50 nm are precipitated. That is, among the ions constituting the metal octylate compound, the metal ion is the largest. Therefore, in a metal octylate compound in which the oxygen ion constituting the carboxyl group of octylic acid is covalently bonded to a 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 a metal octylate compound with this molecular structure is heat-treated in an air atmosphere, the bond between the oxygen ion constituting the carboxyl group and the metal ion is first broken when the temperature exceeds the boiling point of octylic acid, 228°C, and the compound separates into octylic acid and the metal. Furthermore, because octylic acid is a saturated fatty acid, it does not have an unsaturated structure in which carbon atoms are in excess of hydrogen atoms. Therefore, the octylic acid absorbs the heat of vaporization and vaporizes, and the metal precipitates at 290°C, when vaporization is complete. In other words, the carboxylate anion (R-COO) of a carboxylic acid consisting of saturated fatty acid - ), but metal carboxylate compounds that are covalently bonded to metal ions precipitate metal upon thermal decomposition. These metal carboxylate compounds include, in order of decreasing thermal decomposition temperature at which they precipitate metal, metal octylate compounds, metal laurate compounds, and metal stearates. Therefore, by using metal octylate compounds, which have the lowest thermal decomposition temperature, parts, sheets, containers, or components made of foamed metal as described in paragraphs 9, 11, and 13 can be produced inexpensively. Note that, like metal octylate compounds, metal laurate compounds and metal stearates compounds disperse in methanol at nearly 10% by weight and are insoluble 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 metal carboxylic acid compounds made from saturated fatty acids, metal carboxylic acid compounds made from unsaturated fatty acids have an excess of carbon atoms relative to hydrogen atoms, and therefore, upon thermal decomposition, metal oxides are precipitated simultaneously; for example, in the case of copper oleate, cuprous oxide CuO and cupric oxide CuO are precipitated, and the cost of reducing cuprous oxide and cupric oxide to copper is required. In particular, cuprous oxide must be oxidized to cupric oxide in an atmosphere richer in oxygen than the air atmosphere, and then further reduced to copper in a reducing atmosphere, which increases the cost of treatment. For this reason, the carboxylate anion (R-COO) of carboxylic acid made from saturated fatty acids is used as a metal compound that precipitates metals upon thermal decomposition. - ), but metal carboxylate compounds that covalently bond with metal ions 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. Then, when the alkali metal octylate compound is reacted with an inorganic metal compound, metal octylate compounds composed of various metals are produced. Furthermore, octylic acid is a versatile organic acid. Metal octylate compounds are the least expensive 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 that serves as a raw material for angelic acid esters used in acyclic or carbocyclic compound-containing pharmaceuticals. Tiglic acid is a general-purpose industrial chemical used as a raw material for photosensitive resin compositions and adhesives. Therefore, these three monounsaturated carboxylic acids are inexpensive organic compounds. Next, we will explain about diethylene glycol, which belongs to the dihydric alcohols mentioned above. Diethylene glycol is a general-purpose industrial chemical that is used not only in antifreeze but also in brake fluid, lubricants, inks, tobacco additives (humectants), fabric softeners, cork plasticizers, adhesives, paper, packaging materials, paints, etc. [Brief explanation 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 particles forms individual bubbles, and adjacent copper particles form metallic bonds to join the individual bubbles. DETAILED DESCRIPTION OF THE INVENTION

[0020] Example 1 This example involves the manufacture of a collection of balloons coated with the third suspension described in paragraph 7. The first organic compound used 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 used 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 used was copper octoate Cu[OOCCH(C2H5)C4H9]2 (a product of Fujifilm Wako Pure Chemical Industries, Ltd.), which precipitates copper upon thermal decomposition. Note that copper octoate begins to decompose at 228°C in air and is complete at 290°C, precipitating 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, which was then filled into a container inside 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 methanol at 20°C (100 mmHg). This vaporized the methanol from the methanol solution of crotonic acid, and a collection of crotonic acid crystals was precipitated in the container inside the vacuum bell jar. The vacuum bell jar was then opened to atmospheric pressure, and the collection of crotonic acid crystals was removed from the container inside the vacuum bell jar. The vaporized methanol was recovered and reused. The crotonic acid crystal mass was then placed in a 3 cm x 3 cm x 2 cm container. A 3 cm x 3 cm x 1 cm plate was then placed over the crotonic acid crystal mass, and five 0.6 kg weights were placed evenly spaced on top of the plate. The weights were then removed, and an impact acceleration of 0.2 G was repeatedly applied to the sides and bottom of the container in three directions: front-to-back, left-to-right, and up-to-down. After repeating this process of applying a compressive load and impact acceleration three times, the weight was placed on the plate. Since the plate did not move, it was determined that the crotonic acid crystals had been completely crushed. Furthermore, 350 kg (equivalent 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 precipitation of copper octylate crystals. The vaporized methanol was 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 octoate 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. Further, clusters of crushed crotonic acid crystals were mixed with the first suspension to prepare a second suspension. The second suspension was then filled into a container, which was then heated to 35°C to increase the vapor pressure of the crushed crotonic acid crystals in the second suspension. The second suspension was then filled into a container inside a vacuum bell jar, the vacuum bell jar was sealed, and a dry pump was operated to reduce the pressure inside the vacuum bell jar to 100 Pa, lower than the saturated vapor pressure of the first organic compound at 35°C. This resulted in the evaporation of methanol from the diethylene glycol methanol solution, and a third suspension in which clusters of copper octylate crystals were dispersed in diethylene glycol covered the surface of the crushed crotonic acid crystals. Next, the crushed crotonic acid crystals evaporated, and the crotonic acid gas formed balloons, the surface of which was covered with the third suspension. As a result, clusters of balloons covered with the third suspension were produced. The evaporated methanol was recovered and reused. In this example, copper octylate, which precipitates copper by thermal decomposition, was used as the metal compound to form the metal foam from a collection of copper fine particles. However, the metal fine particles that form the metal foam are not limited to copper fine particles. Because the metal octylate compound is a metal compound made of various metals, the metal foam can be formed from a collection of various metal fine particles.

[0021] Example 2 This example is an example in which a part made of foam metal is manufactured in the shape of the bottom surface of a container 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 in the shape of the bottom surface of a container using the collection of balloons covered with the third suspension manufactured in Example 1. A 10 cm x 60 cm x 2 cm container was filled with a portion of the balloon cluster covered with the third suspension prepared in Example 1. The container was then transferred to a heat treatment device in an air atmosphere, where it was heated to 210°C at a rate of 30°C / min, then heated to 290°C at a rate of 10°C / min, and left at 290°C for 1 minute. The container was then removed from the heat treatment device. An impact acceleration of 0.3 G was then applied to four points on the bottom of the container, and a 10 cm x 60 cm plate was peeled off from the container. Three such plates were produced. First, the sheet was dropped 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 ultra-low accelerating voltage SEM from JFE Techno-Research Corporation was used as the electron microscope. This equipment allows observation at ultra-low accelerating voltages starting from 100V, and has the advantage of being able to observe the sample directly without forming a conductive coating on it. First, secondary electron beams between 900-1000V of the reflected electron beam from the sample surface were extracted and image-processed to observe the sample surface. A cluster of 40-60nm granular particles covered the entire surface of the sample. Furthermore, images of secondary electron beams between 900-1000V of the reflected electron beam from the sample cross-section revealed that the clusters of granular particles covered balloons, which in turn formed the sample. The balloons were approximately 650nm in size, and the thickness of the clusters of granular particles covering the balloons was approximately 350nm. The balloons covered by the clusters of granular particles were connected by the clusters of granular particles. Next, the energy and intensity of the characteristic X-rays were image-processed to analyze the type of elements comprising the granular particles in the sample cross-section. These were found to be copper atoms. Observation of the sample revealed that balloons of approximately 650 nm in size were covered with clusters of 40-60 nm copper particles with a thickness of approximately 350 nm, and the balloons covered with clusters of copper particles were connected to each other by clusters of copper particles. Figure 1 shows a schematic enlarged view of a portion of the cross section of the sample. 1 is the balloon, and 2 is the cluster of copper particles. Therefore, the resulting plate is a metal foam consisting of a collection of individual bubbles, with the balloons accounting for nearly two-thirds of the volume of the metal foam. Therefore, not only do the balloons contribute to the weight reduction of the metal foam, but the balloons also have sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption properties, giving the plate excellent sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption properties. Furthermore, because the metal foam is made up of a collection of copper particles, the plate 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 microparticles covering the balloons is determined by the amount of copper octoate 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, metal foams can be formed on the bottom of the container in not only rectangular shapes but also disk or polygonal shapes.

[0022] Example 3 This example 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 in contact with the plane of a 2-m-long first belt conveyor, and the vibration exciter was operated to continuously apply a vibration acceleration of 0.2 G to the plane of the first belt conveyor via the vibration table, alternating in three directions: up and down, widthwise, and lengthwise. After this, a collection of balloons covered with the third suspension was dropped at a rate of 5 g / s from the front end of the plane of the first belt conveyor across the entire 10 cm width of the plane, and the first belt conveyor was moved at a speed of 5 cm / s, forming a sheet consisting of the collection of balloons covered with the third suspension across the entire plane. The leading edge of the sheet that reached the rear end of the plane of the first belt conveyor was transferred to the plane of the second belt conveyor, and the sheet was moved on the plane of the second belt conveyor and continuously passed through a heat treatment device in an air atmosphere. Note that the heat treatment device had a temperature gradient, and by controlling the moving speed of the belt conveyor, the sheet was heated to 210°C at a heating rate of 30°C / min, then heated to 290°C at a rate of 10°C / min, and left at 290°C for 1 minute, and then the leading edge of the sheet was sent out from the heat treatment device, as in Example 2. First, the sheet was cut into 20cm pieces and then dropped from a height of 2m without breaking. This indicates that the sheet has a certain strength. The cut surface of the sheet was then observed using an electron microscope. The electron microscope used was the same as that used in Example 2. As in Example 2, a secondary electron beam between 900-1000V of the electron beam reflected from the surface of the sheet was extracted, and the sample surface was observed. A collection of 40-60 nm granular particles covered the entire surface of the sample. Also, as in Example 2, an image of a secondary electron beam between 900-1000V of the electron beam reflected from the cross section of the sample showed that the collection of granular particles covered balloons, and this collection of balloons formed the sample. The size of the balloons was approximately 650 nm, and the thickness of the collection of granular particles covering the balloons was approximately 350 nm, and the balloons covered by the collection of granular particles were connected to each other by the collection of granular particles. Observation of the sheet showed that, as in Example 2, balloons approximately 650 nm in size were covered with clusters of copper particles approximately 40-60 nm in size and approximately 350 nm thick, and the balloons covered with clusters of copper particles were connected to each other by clusters of copper particles. Therefore, the produced sheet is a metal foam consisting of a collection of single cells, as in Example 2, with the balloons accounting for nearly two-thirds of the volume of the metal foam. Therefore, not only do the balloons contribute to reducing the weight of the metal foam, but the balloons also have sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption properties, giving the sheet excellent sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption properties. Furthermore, because the metal foam is made up of a collection of copper fine particles, the sheet has the properties of copper.

[0023] Example 4 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. Two molds were assembled, with an outer mold having an inner diameter of 20 cm and an inner mold having an outer diameter of 19 cm, so as to form a 5 mm gap between them. A portion of the balloons coated with the third suspension prepared in Example 1 was filled into the 5 mm gap. The mold was then dropped twice from a height of 5 cm to increase the packing density of the balloons coated with the third suspension in the mold gap. The mold was then transferred to the heat treatment device used in Example 3, and the balloons coated with the third suspension in the mold were heat-treated under the same heat treatment conditions as in Example 3. The inner mold was then separated from the assembled molds, removed, and a cylinder with a 5 mm wall thickness was then removed from the outer mold. First, the cylinder was dropped from a height of 2m, but it did not break. This indicates that the cylinder has a certain strength. A portion of the top of the cylinder was cut, and the cut surface was observed under an electron microscope, as in Examples 2 and 3. As a result, as in Examples 2 and 3, balloons approximately 650 nm in size were covered with clusters of 40-60 nm copper particles with a thickness of approximately 350 nm, and the balloons covered with clusters of copper particles were connected to each other by clusters of copper particles. Therefore, as in Examples 2 and 3, the produced cylinder was a metal foam composed of clusters of single cells, and the balloons accounted for nearly two-thirds of the volume of the metal foam. Therefore, not only did the balloons contribute to reducing the weight of the metal foam, but the balloons also possessed sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption properties, resulting in the cylinder having excellent sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption properties. Furthermore, because the clusters of copper particles constitute the metal foam, the cylinder possesses the properties of copper. It should be noted that the container made of foam metal is not limited to a cylinder. It is possible to manufacture a container or 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 metal foam as examples. Because metal foam is composed of a collection of individual bubbles, plates, sheets, and cylinders made of metal foam are not only lighter in weight than bulk materials, but also have the properties of balloons, which are related to sound insulation, sound absorption, heat insulation, vibration damping, and shock absorption. They also have the metallic properties of the metal particles that make up the metal foam.

[0024] Example 5 This example relates to a method for imparting new metallic properties to a part, sheet, container or component made of 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. The silver compound used was diamine silver chloride (a product of Tanaka Kikinzoku Kogyo Co., Ltd.) Diamine silver chloride is an inorganic metal compound containing a silver complex ion in which ammonia is coordinately bonded to the silver ion, and has the composition formula [Ag(NH3)2]Cl. It thermally decomposes at 180°C in a hydrogen atmosphere, precipitating 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, 200 g of 1-propanol CH3(CH2)2OH, which has a boiling point of 98°C and a viscosity of 1.9 mPa·sec at 20°C, was mixed with the methanol dispersion of diammine 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 then immersed in the container, after which 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 heated to 180° C. in a hydrogen atmosphere, and 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, as in Examples 2, 3, and 4. The surface of the plate was covered with silver microparticles of 40-60 nm. Furthermore, observation of the cross section of the plate revealed that the surface of the plate was covered with 2-3 layers of silver microparticles, and that the metal-bonded silver microparticles were layered and covered the plate. Therefore, the foam metal plate composed of a collection of copper microparticles prepared in Example 2 was endowed with the properties of silver, such as catalytic activity. Above, we have shown an example in which the surface of a metal foam consisting of a collection of copper particles is covered with a collection of silver particles. However, the metal particles covering the surface of the metal foam are not limited to silver particles. Because metal compounds precipitate various metals through 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 raw material used in producing a foam metal consisting of a collection of single bubbles is a collection of balloons made of a gas of an organic compound covered with a suspension in which a collection of crystals of a metal compound that precipitates metal by thermal decomposition is dispersed in a collection of a liquid organic compound, and the method for producing said raw material comprises: the first organic compound has a first property of having a melting point higher than 30°C, a second property of having 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 not dissolving or dispersing crystals in a methanol solution of the second organic compound; the first organic compound is dissolved in methanol to prepare a methanol solution of the first organic compound, 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 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, thereby vaporizing the methanol from the methanol solution of the first organic compound and precipitating a collection of crystals of the first organic compound in the container in the vacuum bell jar; and the vacuum bell jar is opened to atmospheric pressure and the collection of crystals of the first organic compound is removed from the container in the vacuum bell jar; The collection of crystals of the first organic compound is filled into a new container, and a plate that covers the entire surface of the collection of crystals of the first organic compound is placed on top of the collection of crystals of the first organic compound. Thereafter, a compressive load is applied to the entire surface of the plate to crush the crystals of the first organic compound in the new container. Furthermore, impact accelerations are repeatedly applied to the side and bottom of the new container in three directions, front-to-back, left-to-right, and up-to-down, to rearrange the crushed collection of crystals of the first organic compound within the new container. Thereafter, the compressive load is again applied to the entire surface of the plate to crush the crystals of the first organic compound. a second step of further crushing the crystals of the first organic compound, and then repeatedly applying the impact acceleration in three directions to the side and bottom of the new container; repeating the pair of steps of applying the compressive load and applying the impact acceleration; and when the plate stops moving when the compressive load is applied to the plate, determining that the crushing of the crystals of the first organic compound is complete, and stopping the pair of steps; and crushing the crystals into crystals of approximately 20 nm in size, which is approximately 1 / 5 the size of the crystals of the first organic compound precipitated in the container; and then removing the plate from the new container; the metal compound is 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, the metal compound being dispersed in methanol to prepare a methanol dispersion of the metal compound, and then the temperature of the methanol dispersion of the metal compound is raised to the boiling point of the methanol to evaporate the methanol from the methanol dispersion of the metal compound, thereby precipitating a cluster of crystals of the metal compound; The second organic compound has 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 at 20°C of 35 mPa·sec or more, a fourth property of the first organic compound not dispersing or dissolving in a methanol solution obtained by dissolving the first organic compound in methanol, and a fifth property of the metal compound not dispersing or dissolving in a methanol solution obtained by dissolving the first organic compound in methanol. a fourth step of weighing out the second organic compound at a weight greater than the weight required to cover the entire surface of the rune with the collection of second organic compounds, and mixing the weighed collection of second organic compounds with methanol at a weight four times greater than the weight of the collection of second organic compounds to prepare a methanol solution of the second organic compound; and then mixing the collection of crystals of the metal compound, the weight of which is less than the weight of the weighed collection of second organic compounds, with the methanol solution of the second organic compound to prepare a first suspension in which the collection of crystals of the metal compound is dispersed in the methanol solution of the second organic compound; a fifth step of mixing the first suspension mass with a mass of crushed crystals of the first organic compound to prepare a second suspension mass in which the mass of crushed crystals of the first organic compound is dispersed in the first suspension mass; The second suspension is filled into a new container in the vacuum bell jar, and 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, and the first suspension becomes a third suspension in which clusters of crystals of the metal compound are dispersed in clusters of the second organic compound, and the third suspension covers the crushed crystals of the first organic compound. Next, the first organic compound is dissolved in methanol and the third suspension becomes a third suspension in which clusters of crystals of the metal compound are dispersed in clusters of the second organic compound. a sixth step in which the crushed crystals are vaporized to form balloons made of the gas of the first organic compound, the surfaces of the balloons are covered with the third suspension and the balloons are bonded together via the third suspension, and a collection of balloons whose surfaces are covered with the third suspension and bonded together via the third suspension is formed in a new container within the vacuum bell jar; thereafter, the vacuum bell jar is opened to atmospheric pressure, and the collection of balloons whose surfaces are covered with the third suspension is removed from the vacuum bell jar; By continuously carrying out all of these six steps, balloons made of the gas of the first organic compound are covered with a suspension in which clusters of crystals of a metal compound that precipitates metal upon thermal decomposition are dispersed in the cluster of the second organic compound, and a cluster of balloons is produced in which the balloons are bonded together with the suspension, and the cluster of balloons is used as a raw material for producing a foam metal made of a cluster of single-cell bubbles.

2. A method for manufacturing a part made of foam metal on the bottom surface of a container using a collection of balloons whose surfaces are covered with the third suspension manufactured by the method according to claim 1 as a raw material, the method comprising the steps of: a container having a bottom surface that corresponds to the shape of a part made of foam metal to be manufactured, filled with a part of a collection of balloons whose surfaces are covered with the third suspension manufactured by the method of claim 1; the container is transferred to a heat treatment device, exposed to an atmosphere in which the metal compound constituting the third suspension is thermally decomposed, and further heated to a temperature at which the thermal decomposition of the metal compound is completed; As a result, 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, and the mixed mixture covers the surface of the balloon. When the container is further heated, the second organic compound vaporizes, and a group of the organic molecules and a group of the metal molecules cover the surface of the balloon. When the container is further heated, the organic molecules begin to vaporize with the heat of vaporization, and the surface of the balloon is gradually covered with a group of the metal molecules. When the container is further heated, the organic molecules When the vaporization of the molecules is completed, the metal molecules covering the surface of the balloon gather together to form metal fine particles, the collection of metal fine particles precipitates all at once on the surface of the balloon, the collection of metal fine particles stacks up, and adjacent metal fine particles form metallic bonds at the contact points, the collection of metal fine particles that have been metallically bonded stacks up to cover the surface of the balloon, and adjacent metal fine particles that have covered the surface of the balloon form metallic bonds, so that the balloons are joined together via the collection of metal fine particles that have been metallically bonded, and a part consisting of the collection of balloons joined by the collection of metal fine particles that have been metallically 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 foam metal in the shape of the bottom surface of a container using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method described in claim 1, by continuously carrying out all of the above-mentioned processes, wherein a part made of foam metal is produced in the shape of the bottom surface of the container.

3. A method for continuously producing a sheet of foam metal using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method of claim 1, comprising the steps of: a container is filled with a portion of the collection of balloons whose surfaces are coated with the third suspension produced by the method of claim 1; Thereafter, for a first belt conveyor having a plane that combines the following three characteristics: a first characteristic in which the width of the plane is wider than the width of the sheet of foam metal to be produced; a second characteristic in which the plane is in contact with a vibration table; a third characteristic in which three-directional vibrations consisting of vertical vibrations, widthwise vibrations, and lengthwise vibrations are alternately and continuously applied to the plane from the vibration table; and a fourth characteristic in which 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, while a predetermined amount of a collection of balloons whose surfaces are covered with the third suspension is continuously dropped from the container onto 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, a group of balloons whose surfaces are covered with the third suspension drips continuously onto the front end of the plane of the first belt conveyor, the width of 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 group of balloons covered with the third suspension that constitutes the coating are continuously rearranged within the group of balloons to make the thickness of the coating uniform, and as a result, 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. Furthermore, for a second belt conveyor having a plane that combines the first feature, the width of the plane is the same as the width of the plane of the first belt conveyor; the second feature, the plane moves horizontally at a predetermined speed; the third feature, 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 undergoes thermal decomposition and is heated to a temperature at which the thermal decomposition of the metal compound is completed; and the fourth feature, 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 synchronization 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 further moves horizontally, causing the sheet to enter the heat treatment device. When the sheet enters the heat treatment device, the temperature of the sheet rises, thermal decomposition of the metal compound that constitutes 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 that constitutes the third suspension, and this mixed mixture covers the surface of the balloon. As the temperature of the sheet further rises, the second organic compound vaporizes, and a group of the organic molecules and a group of the metal molecules cover the surface of the balloon. As the temperature of the sheet further rises, vaporization of the organic molecules begins, accompanied by the heat of vaporization, and the surface of the balloon is gradually covered with a group of the metal molecules. As the temperature of the sheet further rises, 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 up and metal bonds between adjacent metal microparticles at the contact points, the collection of metal microparticles that have metal bonds stacks up to cover the surface of the balloon and the adjacent metal microparticles that have covered the surface of the balloon metal bond together, thereby bonding the balloons together via the collection of metal microparticles that have metal bonds, and a sheet is formed consisting of a collection of balloons bonded together by the collection of metal microparticles that have metal bonds, and the sheet passes through the heat treatment device to continuously form a sheet consisting of a collection of balloons bonded together by the collection of metal microparticles that have metal bonds. A method for continuously producing a foam metal sheet using as a raw material a collection of balloons whose surfaces are covered with the third suspension produced by the method described in claim 1, wherein a foam metal sheet is continuously produced by continuously carrying out all of the above-mentioned processes.

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 of claim 1, comprising the steps of: An outer mold and an inner mold are combined to form a pair of molds, and a gap is formed between the outer mold and the inner mold. Then, a portion 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 between the pair of molds. Furthermore, the pair of molds is dropped 2-3 times onto a flat surface separated by a distance of 5-10 cm, and a drop impact force is applied 2-3 times to the group of balloons whose surfaces are covered with the third suspension filled in the gap between the pair of molds, thereby increasing the packing density of the group of balloons whose surfaces are covered with the third suspension in the gap between the pair of molds. Thereafter, the pair of molds is moved to a heat treatment device, and the pair of molds is exposed to an atmosphere in which the metal compound constituting the third suspension is thermally decomposed, and further, the temperature is raised to a temperature at which the thermal decomposition of the metal compound is completed. As a result, the temperature of the pair of molds rises, 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 that constitutes the third suspension, and this mixed mixture covers the surface of the balloon. As the temperature of the molds further rises, the second organic compound vaporizes, and a group of the organic molecules and a group of the metal molecules cover the surface of the balloon. As the temperature of the pair of molds further rises, vaporization of the organic molecules begins, accompanied by the heat of vaporization, and the surface of the balloon is gradually covered with a group of the metal molecules. As the temperature of the pair of molds further rises, 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, the collection of metal microparticles precipitates all at once on the surface of the balloon, the collection of metal microparticles stacks up and metal-bonds at the sites where adjacent metal microparticles come into contact, the collection of metal-bonded metal microparticles stacks up and covers the surface of the balloon, adjacent metal microparticles covering the surface of the balloon metal-bond together, the balloons are joined together via the collection of metal-bonded metal microparticles, and the collection of balloons joined by the collection of metal-bonded metal microparticles forms a container or part shape that is the same as the shape of the gap between the pair of molds, and the size of the gap between the pair of molds forms the wall thickness of the container or part, and the container or part is formed in the gap between the pair of molds. Thereafter, the inner mold is separated from the pair of molds, the separated inner mold is removed, and the container or the part is further removed from the outer mold. A method for producing a container or part made of foam metal in the 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 described in claim 1, wherein all of the above-mentioned processes are carried out continuously to produce a container or part made of foam metal in the gap of a mold.

5. The method for imparting new metallic properties to a part, sheet, container or component made of a foam metal produced by the method described in claims 2 to 4 includes the steps of: A metal compound is produced by thermal decomposition of a new metal different from the material of the metal constituting the foam metal part, sheet, container, or part manufactured by the method according to any one of claims 2 to 4, and the new metal compound is dispersed in methanol to prepare a methanol dispersion of the metal compound. Furthermore, the organic compound is an organic compound that has a first property of being soluble in or miscible with methanol, a second property of being more viscous than methanol, and a third property of having a boiling point that is higher than the boiling point of methanol and lower than the thermal decomposition temperature of the metal compound that precipitates the new metal by thermal decomposition, and the organic compound is mixed with a methanol dispersion of the metal compound that precipitates the new metal by thermal decomposition, and the mixture in which the organic compound is dissolved in or mixed with the methanol dispersion of the metal compound is filled into a container. 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 part, sheet, container or component made of foam metal is entirely 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 a metal compound that precipitates by thermal decomposition of the new metal is thermally decomposed, and the temperature is further increased to a temperature at which the metal compound that precipitates by thermal decomposition of the new metal is thermally decomposed. As a result, clusters of metal particles made of the new metal are precipitated all at once on the clusters of metal-bonded metal particles that form the surface of the part, sheet, container or component made of the foam metal, and the new metal particles are metal-bonded at the points where they come into contact with each other, and the metal-bonded new clusters of metal particles cover the surface of the part, sheet, container or component made of the foam metal, thereby imparting the properties of the new metal to the part, sheet, container or component made of the foam metal. A method for imparting new metallic properties to a part, sheet, container or component made of foam metal produced by each of the methods described in claims 2 to 4, in which new metallic properties are imparted to the part, sheet, container or component made of foam metal by continuously carrying out all of the above-mentioned treatments.

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

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