JPS61217505A - Production of porous aluminum - Google Patents

Abstract

PURPOSE:To obtain a porous metal in which blank materials are securely and metallurgically bonded by sticking an Al alloy having a low m.p. to the surface of cut Al blank materials and heating the same in a molding tool. CONSTITUTION:The blank material of Al or Al alloy is cut to a wire, fiber of chip shape. The power 2 of the low m.p. alloy such as Al-Pb, Al-Sn or Al-Pb-Sn which is made into a slurry by an aq. or volatile soln. is stuck onto the surface of the cut metallic blank materials 1. Such blank materials are packed after drying into the molding tool, by which the materials are heated to the liquidus line temp. of the low m.p. alloy 2+ or -10 deg.C and are molded under the pressure. The molding is then forcibly air cooled. The porous aluminum in which the low m.p. alloy 2 intrudes deeply into the recessed parts on the surface of the cut blank material metals 1 so as to be welded and mechanically bonded to each other can be molded to a desired shape by the above-mentioned method. Such porous aluminum permits easy bending, machining, etc.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for producing porous aluminum.

[Conventional technology]

Various methods have been proposed to produce porous metals, including a sintering method that utilizes the diffusion phenomenon of metal atoms caused by external thermal energy at the interface between two contacting powder metals. As a manufacturing method that utilizes the porosity of other materials, there is an incineration method in which metal is attached to the surface of expanded polystyrene using a surface treatment method such as electrodeposition, and then the expanded polystyrene is burned to obtain a mesh-like porous metal. By baking water-soluble particles such as sodium chloride into a predetermined shape,
There is an elution method in which a molten metal is injected under pressure into the gaps between the particles and solidified, and then the sodium chloride is dissolved in water to obtain a network-like porous metal.
A foaming method is known in which a porous metal is obtained by adding a gas generating compound such as a hydride of r to supersaturating the gas content of the molten metal and solidifying the metal to create a porous metal.

[Problem that the invention seeks to solve]

However, in the above sintering method, it takes several hours for the metal atoms to diffuse, and if there is dirt or foreign matter on the contact surface, the diffusion rate is extremely reduced and the bonding force between the metals is weakened. In addition, in the incineration method or elution method that utilizes the porosity of other materials, styrofoam oxides and sodium chloride may be deposited inside the porous metal. There is a risk of residual particles, etc., and since the thickness of the metal body becomes thinner, there are problems such as low mechanical strength.Furthermore, in the foaming method, there are variations in the location of pores, and the molten metal There was a problem in that the temperature distribution, especially near the bottom of the furnace and near the surface of the molten metal, had a large temperature difference, and the solidification rate also depended on the size of the pores, resulting in uneven pore distribution and unstable quality.

In addition to the above, lightweight particle diffusion methods are also known,
The porous metal produced by this method has an extremely low porosity and cannot be called a true porous metal.

[Means for solving problems]

The present invention was devised in view of these points of view, and has good productivity and workability, allows for arbitrary control of pore size and porosity, and has strong intermetallic bonds and no residual foreign matter. The present invention provides a method for producing porous aluminum.

That is, the present invention provides wire rods or plate materials in the form of wires, fibers,
Al-Pb system on the surface of aluminum or aluminum alloy material made into chips or the like.

Aqueous slurry or volatile solution slurry of Aj-Sn-based or Al-Pb-Sn-based alloy powder is applied and dried, then placed in a mold, etc., and heated in a heating furnace, etc. This is a method for producing porous aluminum in which the materials are heated to the liquidus temperature of the alloy ±10°C, and the materials are fused to each other with the alloy and formed into a desired shape. AN-Pb series, Aj-Sn
An aqueous slurry or a slurry of a volatile solution made by mixing a powder of an Al-Pb-Sn alloy or an Al-Pb-Sn alloy with a flux is attached and dried, and then placed in a mold, etc. The liquidus temperature of the above alloy in a heating furnace, etc.
This is a method for producing porous aluminum, in which the materials are heated to 10° C. and fused together using the alloy, and formed into a desired shape.

(Function) In the method of the present invention, the surface of the metal (1) in the form of lines, fibers, chips, etc., preferably on the surface of the material on which fine irregularities are formed by etching with a caustic soda solution, etc. When a powder of a low melting point metal (2), such as an Al-Sn alloy, whose melting point is lower than that of the material is attached, the surface of the material becomes as shown in Fig. 1, and this is placed in a mold for forming. As shown in Figure 2, linear, fibrous,
Metal chips (1), such as chips, are mechanically intertwined to form a large number of lateral contact points.

When the low melting point metal (2) is heated to its melting point in this state, the low melting point metal (2) attached to the surface of the material melts, and the surface of the material as shown in Figure 3 (a) and (b). As the low melting point metal (2) is fused to each other as it penetrates deeply into the uneven portion, the fused low melting point metal (2) causes the metal (1) in the shape of a wire, IIH, chip, etc. They are mechanically and metallically bonded to each other to form a porous metal.

〔Example〕

Hereinafter, the method for producing porous aluminum lamb of the present invention will be specifically explained based on Examples.

First, a continuous casting billet (diameter 100φ) of A-6063 fulminium alloy was machined using a lathe, and the width was approximately 11wR1.
A fibrous material with a length of about 300 seconds is obtained, and this material is degreased and washed with ethyl alcohol to obtain a fibrous metal (1).

On the other hand, powder of AJ2 aluminum alloy with an average particle size of 10 μm composed of a low melting point metal (2) having a melting point lower than that of the metal (1), for example Al-Sn, is added to the surface of the metal (1) in ethyl alcohol. The resulting slurry was applied using air spray and dried.

Here, the composition of the above A-6063 aluminum alloy is M
Q: 0.6% by weight, Si: 0.4% by weight, Fe: 0.1
% by weight, while the composition of the AJ2 aluminum alloy is Sn-near. Cu: 0% by weight, Cu: 2.0% by weight.

Note that the above metal (1) includes pure aluminum, Aj
-Mq based alloy, AJ-Mn based alloy, Al-Ma-8i based alloy, Al-Cu based alloy, AlAl-7n- based alloy, etc. Also, as the low melting point metal (2), Sn component 4 Any Al-Sn alloy containing up to 50% by weight may be sufficient, and furthermore, each component of Pb and 5n-Pb may be added to 4% by weight.
Aj-Pb system containing ~50% by weight, or Aj-Pb-
It may be a Sn-based alloy (or a plurality of the above alloys may be used in combination).

Next, the metal (1) with the above-mentioned low melting point metal (2) adhered to its surface is put into a mold for filling, and then the mold is placed in a heating furnace in a nitrogen gas atmosphere, and the metal (1) with a low melting point metal (2)
It was heated to the liquidus temperature of ±10°C.

After the mold reaches the above temperature, the mold is taken out of the heating furnace, and after forced air cooling (using a fan in this embodiment), the porous aluminum is taken out from the mold.

In this example, the low melting point metal (2
), the metal (1) is fused by melting the low melting point metal (2), but the low melting point metal (2) only needs to be in a state where an adhesion effect can be obtained to the metal (1); It is not necessary to bring the melting point metal (2) into a completely molten state, and the melting point metal (2) may be in a semi-molten state.

Further, in the above example, slurry-formed AJ2 aluminum alloy powder is adhered to the surface of the fibrous metal (1) using an air spray method, but a flux of aluminum fluoride potassium salt is applied to the surface of the fibrous metal (1) at a rate of about 1 g/100 Cc. The same purpose can also be achieved by adding it to ethyl alcohol at a ratio of 1,000 ml, mixing it with the AJ2 aluminum alloy to form a slurry, and applying this slurry to the surface of the metal (1) using an air spray method. In addition to the aluminum potassium fluoride salt, the above-mentioned flux may be any other conventionally known flux, preferably a non-corrosive flux.

Furthermore, although a nitrogen gas atmosphere heating furnace is used as the heating furnace, it may be a normal heating furnace or a heating furnace that combines a heating furnace with an inert gas atmosphere and a vacuum heating furnace.

Furthermore, although the above slurry was applied using an air spray, it may be applied by dipping, or simply painted, and the method of application is arbitrary.

Moreover, the shape of the porous aluminum product is formed into a desired shape such as a circle, square, triangle, or polygon using a mold.

〔Effect of the invention〕

According to the method for producing porous aluminum of the present invention: (a) Compared to conventional sintering methods, heating and holding times are shortened, productivity is significantly improved, and costs can be reduced.

(b) Conventional sintered metals and foamed metals are brittle and have poor workability, whereas the products obtained by the present invention have extremely high mechanical properties, especially ductility (elongation), and can be easily processed by bending, cutting, etc. is easy.

(c) In the case of the conventional method, the pore size and porosity depend on the manufacturing method and the effective range is narrow, but with the method of the present invention, the pore size and porosity can be changed arbitrarily by simply changing the shape of the material. , its control range is wide.

(d) Since the metal bond is strong, it is resistant to heat shock and can be welded, for example.

(E) There is very little foreign matter contamination or residual foreign matter.

(f) The heat transfer coefficient is significantly improved due to the significant increase in the heat transfer area.

(g) It has electrical conductivity and has a high current collecting effect.

[Brief explanation of the drawing]

1 to 3 are explanatory diagrams showing the state in which metal materials are bonded to each other in the method of the present invention. Symbol explanation (1)...Metal, (2)...Low melting point metal, Patent applicant: Nippon Light Metal Co., Ltd. Representative Patent attorney: Satoshi Nakamura
Hiroshi (2 others) Figure 1, Figure 3 (A) Figure 2, (B) 2: Low Shao, Jiu Kinen

Claims (5)

[Claims] (1) Al-Pb based, A
An aqueous slurry or a volatile solution slurry of l-Sn or Al-Pb-Sn alloy powder is deposited and dried, and then the liquidus temperature of the alloy is adjusted to ±10
1. A method for producing porous aluminum, which comprises heating the above materials to a temperature of 0.degree. C. to fuse and shape the materials with the alloy. (2) In each of the above alloys, Pb, Sn or Pb-
Claim 1, wherein the Sn component is 4 to 50% by weight
The method for producing porous aluminum as described in Section 1. (3) Al-Pb series, A
An aqueous slurry or a volatile solution slurry made by mixing l-Sn or Al-Pb-Sn alloy powder and flux is deposited and dried, and then the liquidus line of the alloy is A method for producing porous aluminum, which comprises heating to a temperature of ±10° C. to fuse and shape the above-mentioned materials with the above-mentioned alloy. (4) In each of the above alloys, Pb, Sn or Pb-
Claim 3, wherein the Sn component is 4 to 50% by weight
The method for producing porous aluminum as described in Section 1. (5) The method for producing porous aluminum according to claim 3, wherein the flux is a KF-AlF_3-based flux.