JPS58204137A - Manufacture of porous metallic body - Google Patents

Abstract

PURPOSE:To manufacture a porous metallic body having a skeleton composed of fine metallic bodies by a simple method by kneading an org. polymer binder with fine metallic bodies, applying the kneaded material to a substrate of network foamed synthetic resin, and burning out the substrate and the binder by heat treatment. CONSTITUTION:A binder contg. an org. high molecular compound as the principal component is kneaded with fine metallic bodies as a base material. The kneaded material is applied to the skeleton of foamed synthetic resin having three-dimensional network structure by dipping or other method. The skeleton and the binder are then burned out by heat treatment, and the fine metallic bodies are sintered by heat treatment in a nonoxidizing atmosphere. Thus, a porous metallic body having three-dimensional network structure is obtd. simply and easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel and simple method for manufacturing a porous metal body having a three-dimensional network structure.

A conventional method for producing a three-dimensional mesh porous metal body is disclosed in Japanese Patent Publication No. 47-10524. As shown in Figure 1, the process of this method is to treat the reticulated foamed synthetic resin with carbon or graphite to make it conductive, and then electrodeposit a metal such as Ni in a plating bath. , the internal synthetic resin is burnt out or partially burnt out to form the electrodeposited metal as the skeleton of the porous body. This method is still used today as the first effective and practical method for producing three-dimensional mesh porous metal bodies.
On the other hand, there are problems with the process and equipment, such as the need for conductive treatment beforehand in order to electrodeposit the metal, and the need for an electrodeposition device such as a power source and plating cypress. In addition, the electrodeposition speed is determined by many factors such as the resistance value of the surface of the reticulated foamed synthetic resin due to conductive treatment, power supply voltage, metal ion concentration in the plating solution, current density, and plating time, so all of these factors must be adjusted. Otherwise, there were problems in that the amount of metal electrodeposited could not be adjusted, which was complicated in terms of process control, and that it was impossible to obtain a product made of an alloy of two or more types.

The present invention eliminates the drawbacks of the above-mentioned conventional methods and provides a novel method for producing a porous metal body that is simple and easy to control the process. That is, as shown in the process diagram of FIG. 2, the method of the present invention is similar to the conventional method in that a reticulated foamed synthetic resin is used as the starting base material, but the process and process control of the conventional method are complicated. 1, without using conductive coating treatment or electrodeposition treatment.

As an alternative, heat treatment can be performed after applying a mixture of organic polymer binder and metal microscopic objects by dipping or spraying on the base material, thereby burning out the base material and the binder and removing the metal microscopic objects. This process uses a process of sintering the material to form a skeleton.

Hereinafter, the present invention will be described in detail according to the illustrated embodiments.

[Example 1]: A polyurethane foam having a three-dimensional network structure (trade name: Everlite Scotto, manufactured by Prigiston Tire Co., Ltd.) was used as a starting base material. A mixture obtained by mixing the composition of Composition Example 1 below in a ball mill for about 1 hour was uniformly applied to this urethane skeleton by spraying. 1. Apply the coating at room temperature.
After drying at 120℃ for 1 minute, dry at 880℃ for 50 minutes.
Bake for a minute.

(Composition example 1.) Binder (urethane varnish) 38% by weight Microscopic metal (
(AI powder) 42 Additives (aerosil, curing agent, thinner) 25 Then, by firing in a hydrogen stream at 520°C for 2 hours, an aluminum product with a three-dimensional network structure as shown in Figure 3 is produced. A porous metal body was obtained. In Figure 8 (1)
is a skeleton, and (2) is a hole. When this surface was observed with a scanning electron microscope, a phenomenon as shown in the schematic diagram of FIG. 4 was observed. That is, before firing in a hydrogen stream, the A1 powder particles (3) are only densely dispersed, as shown in Figure 4(a), but after firing, as shown in Figure 4(b). ), it was found that the AI powder particles (3) mutually thinned (sintered) at the interface and were bonded at the neck portion (4).

Since Al metal porous bodies can essentially be subjected to AI plating (electrodeposition),
524 cannot be manufactured using conventional methods.1
However, the method of the present invention has the advantage that it is possible to produce an A1 porous body with a three-dimensional network structure.

[Example 52. ] Example 1. Using the same polyurethane foam as in the case of the following composition example 2. The mixture was mixed in a ball mill for about 1 hour, the viscosity was adjusted, and the mixture was applied by dipping. After drying the coated material for 2 times at 120°C, 8 tests at 180°C and 2 times at 600°C in a vacuum of 10-5 torr.
After firing for a period of time, a three-dimensional network porous body having a structure as shown in FIG. 8 was obtained.

(Composition Example 2) Binder (polyester varnish) 25 gfi% Microscopic metal (Fe-Ni powder, AI powder) 58 Additives (curing accelerator, silica, thinner) 17 wt% This was also carried out. Example 1. When the surface was observed using a scanning electron microscope in the same way as in the case of Figure 4(b), it was found that the particles were sintered together by thinning. As a result, at the interface between Fe-Ni powder and AI powder,
It was found that due to the firing in vacuum, the atoms of the two atoms diffused into each other, resulting in the formation of a Fe-Al alloy.

Next, Example 1. The bending workability of the two types of porous metal bodies manufactured in 2 and 2 was investigated. Both thickness 5jl
Prepare a plate-like object with jl, and hold it at 60 degrees against the horizontal surface.
When the sample was bent to zero, no cracks were observed at the bent portion, indicating that it had good bending workability.

By the way, as the binder made of an organic polymer compound used in the present invention, in addition to the urethane and polyester varnishes used in the examples, melasin, acrylic, epoxy, polyethylene styrene, etc. can be used, and the form may vary. It is easy to use a face-shaped product prepared by dissolving the initial polymer of these organic polymer compounds in a solvent.

As for the microscopic metal, powdery ones as used in the examples are suitable for mixing with the binder, but other shapes such as microscopic fibrous or whisker-like metals can also be used. Moreover, any kind of metal or alloy may be used.

As a synthetic resin foam having a three-dimensional network structure, the polyurethane foam used in the examples is the most common and is highly available on the market, but other synthetic resins with an open cell structure, such as silicone, PVC, Even if styrene, polyester, or the like is used, the same porous metal body as in the example can be obtained.

In order to apply the mixture of binder and microscopic metal to this synthetic resin foam skeleton, general coating methods such as spray coating, dipping, and flow coating may be used. A uniform porous metal body can be obtained by controlling the process by controlling the viscosity of the coating material and the amount of coating.

By the way, when baking the coating, an atmosphere such as air, oxygen gas, or inert gas may be used. In this case, the synthetic resin skeleton may be completely burnt out, half burnt out, or carbonized and remain. However, when bonding (sintering) the microscopic metals to each other through subsequent heat treatment, it was difficult to sinter them in an oxidizing atmosphere such as air, and a brittle product was created. As in the examples, it is necessary to conduct the reaction in a non-oxidizing atmosphere such as a hydrogen stream, an inert gas, and a vacuum. In this case, in the example, the microscopic metals are bonded using sintering and diffusion bonding, but they may also be bonded by liquid phase sintering even if a low melting point metal such as a brazing material is used. I can't help it.

As explained above, the process involves kneading the microscopic metal, which is the main material, into a binder mainly consisting of an organic polymer compound, and applying the mixed material to the skeleton of a synthetic resin foam having a three-dimensional network structure. process, heat treatment of the coated material to burn out, semi-burn or carbonize the skeleton of the synthetic resin foam and the organic polymer compound that is the binder, and sintering of the microscopic metal by heat treatment in a non-oxidizing atmosphere. If the method for producing a porous metal body of the present invention includes the step of
Not only can metal porous bodies with a three-dimensional network structure be obtained using a simple and easy-to-manage method, but also those made of A1□ and those made of two or more types of alloys, which could not be obtained using conventional methods, can also be obtained. be able to. Therefore, it is an extremely advantageous method for producing various metal porous bodies.

[Brief explanation of the drawing]

FIG. 1 is a manufacturing process diagram of a conventional metal porous body, FIG. 2 is a manufacturing process diagram of a metal porous body of the present invention, and FIGS. 8 and 4 are:
FIG. 1 is a schematic diagram showing a porous body obtained according to an example of the present invention. (1) is the skeleton, (2) is the pore, (3) is the particle, and (4) is the joint. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Makoto Kuzuno - Figure 1 Figure 2

Claims (1)

[Claims] A process of kneading a microscopic metal as the main material into a binder mainly consisting of an organic polymer compound, a process of applying the mixed material to the skeleton of a synthetic resin foam having a three-dimensional network structure, and a heat treatment of the applied material. and burning out or semi-burning or carbonizing the synthetic resin foam skeleton and the organic polymer compound as the binder, and sintering the microscopic metal by heat treatment in a non-oxidizing atmosphere. A method for manufacturing a porous metal body.