JPS62174362A - Production of porous material - Google Patents

Abstract

PURPOSE:To easily obtain a porous material having a high internal porosity by thermally spraying a substance forming a porous structural material and a substance acting as a blowing agent under control. CONSTITUTION:At least two kinds of substances, that is, a substance forming a porous structural material and a substance acting as a blowing agent are fed to a flame at a high temp., melted and sprayed on a body as molten fine particles to form a deposited layer consisting of a matrix phase and an independent phase having a lower b.p. than the matrix phase. The body having the deposited layer is heated to a temp. at which the layer is expanded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a porous material, and more particularly to a method for manufacturing a porous material by applying a thermal spraying method.

[Prior art and its problems]

Porous materials, such as porous metal materials, are used for various purposes such as high-temperature filters, metal food media, and sound-absorbing materials. In particular, layered porous materials with high internal porosity and low overall apparent specific gravity are desired. There is.

For example, conventional methods for manufacturing porous metal materials include press-molding metal powder, or absorbing gas into metal in a molten state, and then foaming the absorbed gas during resolidification. Are known. however,
In the method of press-molding powder, the internal porosity is low, and if the porosity is increased, a sufficient molded body cannot be obtained.

In addition, in the method of causing foaming by absorbing gas into the molten metal, there is a possibility that the molten metal causes segregation of bubbles, resulting in non-uniform pore distribution.

This invention was made in view of the above-mentioned circumstances, and its purpose is to provide a porous material having a large internal porosity, a small apparent specific gravity as a whole, and a uniform pore distribution. For example, it is an object of the present invention to provide a method by which porous metal materials can be manufactured.

[Method for solving problems]

The present inventors have found that it is effective to achieve the object of the present invention by using a method of thermal spraying a mixture of a substance to be used as a structural material and a substance to be used as a foaming agent, and have completed the present invention. That is, the method for producing a porous material of the present invention involves supplying at least two types of substances to a high-temperature flame, melting them, and spraying the molten fine particles onto an object to be thermally sprayed, thereby forming a matrix phase and a boiling point of the matrix phase. The process involves forming an adhesive layer consisting of an independent phase having a low boiling point and then heating the adhesive layer to a temperature at which the adhesive layer foams.

In a preferred embodiment of the invention, the material forming the matrix phase and the material forming the independent phase can each be sprayed onto the object to be thermally sprayed from different high temperature flames.

Alternatively, the material fed to the high temperature flame can be metal.

In another preferred embodiment, the material forming the matrix phase may be iron, and the material forming the independent phase may be lithium.

In yet another preferred embodiment, the material forming the matrix phase can be ceramic.

In another preferred embodiment, the high temperature flame can be a plasma flame.

Hereinafter, the present invention will be explained in detail.

In this method, at least two substances are supplied to a high temperature flame and heated. The high-temperature flame can be formed by conventional techniques, such as a flame associated with combustion of fuel gas, a plasma flame, and the like.

The type of high-temperature flame can be changed as appropriate depending on the object to be heated. The materials supplied to the hot flame are at least two types in the method of the invention, one forming the porous structure and the other acting as a blowing agent. The boiling point of the construction material is therefore higher than the boiling point of the blowing agent. Examples of the types of materials fed into the high temperature flame include metals and ceramics. The combination of the substance 2 used as a structural material and the substance used as a blowing agent is contrary to the purpose of this invention.
There are no restrictions as long as

That is, when heated to foam diopter, the construction material softens or liquefies, the blowing agent material vaporizes, and - the building material and the blowing agent material are V-soluble in each other. However, as long as a blowing agent independent phase can be formed in the structural material matrix, it may be dissolved to some extent.

Examples of metals include a combination of iron and lithium, a combination of chromium and bismuth, and a combination of perilium and zinc. In these combinations, the amount of lithium sprayed on iron is about 0.1-0.5% by weight, the amount of bismuth is about 1-5% on chromium, and the amount of zinc is 5-15% on beryllium. That's about it.

In this invention, a substance heated and melted by a high-temperature flame is sprayed onto an object to be thermally sprayed. A normal thermal spraying device can be used for this spraying. FIG. 1 shows Example 1 of a thermal spraying apparatus.

This equipment consists of 2 thermal spray guns, 21 cylinders, and 3 acetylene cylinders.
, an oxygen cylinder 4 and an fFA feeder (not shown), and are sprayed onto an object to be thermally sprayed (not shown). In this invention, materials with different thermal properties are sprayed. Therefore, it is desirable that thermal spraying be carried out under conditions such as flame temperature suitable for the feed material. As shown in FIG. 1, spraying may be carried out using a plurality of thermal spraying devices, one of which is a low melting point device and the other is a high melting point device.

Furthermore, by changing the position at which the raw material is supplied to the high-temperature flame, thermal spraying conditions suitable for each material trap can be obtained.

When using this thermal spraying device, it is desirable that the spraying atmosphere be non-oxidizing. For example, inside the thermal spraying chamber to3
The pressure is reduced to ~lQ'Pa, and then an inert gas such as argon is introduced to create an inert atmosphere.

Further, the pressure is reduced to create a vacuum atmosphere.

The substance supplied to the high-temperature flame, for example metal powder, is introduced into the gun nozzle 9 via the raw powder supply pipe 7, as shown in FIG. 13. The raw material powder heated and melted in the flame 13 becomes molten fine particles 14, which are sprayed onto the thermal spray body 16, where they are cooled and solidified.

In this invention, the molten fine particles sprayed onto the object to be thermally sprayed form an adhesion layer 18 on the surface of the object to be thermally sprayed.

This adhesion layer 18 consists of a matrix phase and an independent phase.

A cross-sectional view showing the outline of this adhesion layer is shown in FIG. In this example, an adhesion layer 18 is formed on the surface of the object 16 to be thermally sprayed, and the interior of this layer consists of a continuous matrix addition and a discontinuous independent phase percentage. This matrix phase should become a porous structural material after foaming, and the independent phase should vaporize during foaming and become a blowing agent for the matrix phase. Therefore, the boiling point of the matrix phase i−
The boiling point of the independent phase is higher.

The resulting soaked layer is heated and foamed in the method of this invention. The heating temperature (foaming temperature) is determined by the softening point or melting point of the matrix phase and the boiling point of the independent phase. Therefore, the foaming temperature is determined by the types and combinations of raw materials used. FIGS. 4 and 5 schematically show examples of porous materials obtained according to the present invention.

FIG. 4 shows a porous material 26 with bubble-like pores 24, and FIG. 5 shows a porous material 26 with burst-like pores 24.

〔Example〕

The invention will be explained by the following specific examples.

Example 1 Iron powder and lithium filled in a resin tube were prepared, and both metals were thermally sprayed onto an object to be thermally sprayed using the thermal spraying apparatus and conditions shown in FIGS. 1 and 2. The amount of lithium sprayed relative to iron was 0.1 to 0.5 in terms of weight ratio.

The adhesion layer obtained by thermal spraying was heated to a temperature above the boiling point of lithium of 16,000 and near the temperature at which iron softens and melts to form a porous metal.

The internal porosity of the obtained porous metal was as high as 30 to 50 cm.

9! Example 1 was carried out in the same manner as in Example 1, except that an iron alloy powder in which carbon was added to I 2 iron was used. The internal porosity of the obtained porous metal was as good as in Example 1.

[Action and effect of the invention]

This invention operates as follows and can provide various effects.

(at In this invention, two or more substances, a porous structural material and a foaming agent, are thermally sprayed, so it is necessary to adjust the amount of each sprayed, especially the amount of the foaming agent, at the time of thermal spraying. Therefore, the internal porosity of the obtained porous material can be easily controlled, that is, a porous material with a large internal porosity can be manufactured. Both a cellular porous material and an explosive porous material can be produced using the method.

(1)) Since the foaming agent and structural material are sprayed by thermal spraying, the independent phase of the foaming agent can be uniformly dispersed in the matrix phase of the structural material, resulting in a uniform porous material with no uneven internal pores. can be manufactured.

(c) Among two or more substances in this invention,
Since one is softened or molten and the other is vaporized and foamed to create a porous material, it can be applied not only to metals but also to ceramics.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an example of a thermal spraying apparatus that can be used in the present invention, Fig. 2 is an explanatory diagram showing a state of spraying from a thermal spray nozzle, Fig. 3 is a sectional view schematically showing an adhesion layer, and Fig. 4
FIG. 5 and FIG. 5 are cross-sectional views showing an outline of the porous material. ■... Thermal spray drawing, 2... Thermal spray gun, 9... Gun nozzle, 13... Flame, 14... Fine particles, 16... Thermal sprayed object, 18... Adhesive layer, addition...・Matrix phase,
Otsu...Independent Minister, U...Kou. Original representative Sato - Engraving of the drawings (no changes to the contents) Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Procedural amendment (method) % formula % 1. Indication of the case 1986 Year Patent Application No. 14563 2゜Name of Invention Method for Manufacturing Porous Materials 3 Relationship with the Amendment Case Patent Applicant (307) Toshiba Corporation 1, Agent (Postal Code 100) 6428 Patent Attorney Sa Fuji - Yuj, Date of amendment order: March 5, 1986 (Delivery date: March 25, 1986) 6. Drawing subject to amendment 7, Contents of amendment: Engraving of the drawing (no change in content).

Claims (1)

[Claims] 1. Supplying at least two kinds of substances to a high-temperature flame and melting them;
A molten particulate material is sprayed onto the object to be thermally sprayed to form an adhesion layer consisting of a matrix phase and an independent phase having a boiling point lower than that of the matrix phase, and then the adhesion layer is heated to a temperature at which the adhesion layer foams. A method of manufacturing porous materials including. 2. The manufacturing method according to claim 1, wherein the material forming the matrix phase and the material forming the independent phase are each sprayed onto the object to be thermally sprayed from different high-temperature flames. 3. The manufacturing method according to claim 1 or 2, wherein the substance supplied to the high temperature flame is a metal. 4. The manufacturing method according to claim 3, wherein the substance forming the matrix phase is iron and the substance forming the independent phase is lithium. 5. The manufacturing method according to claim 1 or 2, wherein the material forming the matrix phase is ceramic. 6. The manufacturing method according to any one of claims 1 to 5, wherein the high temperature flame is a plasma flame.