JPS583999B2 - Method for manufacturing composite material consisting of ceramics and metal - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing a composite material consisting of ceramics and metal, and more specifically to a method for manufacturing a composite material consisting of ceramics and nickel or an alloy thereof (hereinafter collectively referred to as "metal foam"). The present invention relates to a method of manufacturing a composite material in which the following materials are integrally bonded together.

Composite materials in which ceramics and metals are bonded are suitable for use as walls of heat-resistant vessels in addition to other materials.

This type of heat-resistant vessel wall can be used in part or all of machinery or equipment to enable high-temperature operation, but it has been pointed out that it is susceptible to thermal stress failure due to temperature gradients inside the vessel wall. has been done.

In addition, since this heat-resistant vessel wall is generally used in high-temperature conditions, it must have a structure that can withstand harsh environments and atmospheres under thermal stress.For this reason, a method is used to strongly bond the ceramic and metal that make up the vessel wall. is strongly requested.

A heat resistant vessel wall structure has been developed which can considerably meet the above requirements.

This is a combination of ceramic and metal, in which the metal concentration changes between the ceramic and the metal.A typical structure is a ceramic with a porosity of about 40 coefficients stabilized with Kalusha or Ittria. ZrO between the zirconia (Zr02) layer and the nickel alloy layer
2-A NiCr-based mixture layer is provided.

At this time, the NiCr content of this mixture layer increases as it approaches the nickel alloy layer, and the portion in contact with the nickel alloy layer is made of NiCr and is integrally heated and soldered.

The manufacturing method for this heat-resistant container wall structure involves wet mixing the components of each layer, stacking them to form the above structure, forming them by cold pressing, and then contacting them with a bonding metal (nickel alloy layer) after drying. It is fired in an inert atmosphere.

Therefore, this method requires complicated process operations such as forming a metal-ZrO2 layer adjusted to a predetermined concentration, press forming while maintaining this state, and firing in an inert atmosphere. It is.

The present inventor has been conducting intensive research on the wall structure of heat-resistant containers, and in this research, he came up with a new idea of using metal foam as the metal when preparing a composite material of ceramics and metal. As a result of continuing various research, they finally discovered that ceramics and metal foam can be bonded with great adhesive strength by interposing copper or an alloy containing copper, and finally completed the present invention.

That is, the present invention relates to a method for producing a composite material consisting of ceramics and metal, characterized in that copper or its alloy is interposed between a foam of nickel or its alloy and ceramics, and the mixture is heated in an oxidizing atmosphere. It is.

The method of the present invention involves interposing copper or its alloy between ceramics and nickel or its own foam, and heating it in an oxidizing atmosphere to firmly bond the ceramic and the foamed material. It has a completely unprecedented feature in that it is applied to this type of heat-resistant vessel wall structure.

The ceramics used in the present invention include silica-based, alumina-based, magnesia-based, zirconia-based, and lanthanum chromite-based ceramics.

The metal foam used in the present invention is a nickel-based foam or an alloy foam made of at least two of nickel, iron, and chromium.

This metal foam usually has a porosity of about 85 to 98 coefficients and a specific surface area of about 500 to 9000 m2/m3, and may be closed cell, open cell foam, or a mixture of these, but open cell foam may be used. It's more or less desirable.

The porosity was measured as follows.

Specifically, specific examples of the foam include various product numbers of "Celmet" manufactured by Sumitomo Electric Industries, Ltd.

Examples of copper or an alloy thereof to be interposed between the ceramic and the metal foam include alloys such as copper, copper-iron, and copper-nickel.

In the present invention, the shapes of the ceramic and metal foams are not particularly limited, and may be appropriately determined from a wide range depending on the purpose of use; representative examples include plate shapes and tube shapes. I can do it.

Moreover, as copper or its alloy, those having an appropriate structure such as a plate shape, a powdery granule shape, etc. can be used.

The amount of steel or its alloy to be used is sufficient as long as it can join the ceramic and the foam, and is appropriately selected depending on the shapes of the two.

When carrying out the present invention, copper or its alloy is interposed between the ceramic and the metal foam, and the
Heating is performed at ~1200°C, preferably 1100-1150°C.

Examples of the oxidizing atmosphere at this time include air, oxygen, a mixed gas of air or oxygen, and a mixed gas of an inert gas and oxygen, and among these, air is particularly preferred.

The composite material obtained by the present invention has a structure in which ceramics and metal foam are heated and integrated via copper or an alloy thereof.

More specifically, the ceramic, the metal foam, and copper or its alloy, or the copper or its alloy oxidized by heating, are melted and integrally joined together.

On the ceramic side, the molten compound has a structure in which the surface of the ceramic is slightly impregnated, while on the metal foam side, the surface part has a structure in which the molten compound is sufficiently impregnated into air bubbles, which is extremely It can be said that the two are integrally joined by strong force via copper or its compound.

The present invention will be specifically explained below by showing actual cases.

However, in the following examples, parts or parts refer to parts by weight or parts by weight unless otherwise specified.

Example 1 Between the 15x15x5mm magnesia plate (purity 995%) and the nickel-based foam metal "Celmet≠3", 15
A copper plate (purity 99.9%) of X15X5mm is interposed,
After heating in air at 1150° C. for 20 minutes, it was taken out of the oven and allowed to cool naturally.

In the obtained composite material, the copper in an oxidized state was impregnated into the metal foam to a certain degree of thickness, and the ceramic was also impregnated to some extent and was strongly integrated.

The tensile strength was measured and found to be 340 kg/cm2.

We also measured the thermal shock resistance by reheating it at 1,200°C for 10 minutes, taking it out of the furnace, and immediately putting it into water several times. As a result, no peeling occurred at the joint, and the surface of the ceramic plate Only some cracks were visible.

Also, its chemical stability is 5% at 70℃ in 48% KOH aqueous solution.
There was no change at all even after immersion for 0 hours.

Furthermore, Celmet used as a metal foam is oxidized due to high temperature baking.

This causes strength deterioration and the like.

In order to prevent this, the above strength deterioration could be prevented by applying heat-resistant enamel to the Celmet surface as a pretreatment.

Furthermore, as means other than heat-resistant enamel, nickel-chromium alloy foam, plating, vapor deposition, high-frequency sputtering, painting, etc. are also effective.

Example 2 15x15x5mm magnesia plate (purity 99.5%)
and a nickel plate (99.9% purity).
1150°C in an atmosphere containing IOV% oxygen mixed with air with a copper plate (purity 99.9) of 5mm
After heating for 20 minutes, the mixture was taken out of the oven and allowed to air.

The tensile strength of the resulting composite material was measured and was found to be 350k.
g/cm2.

Example 3 In place of the magnesia plate in Example 1 above, a predetermined ceramic plate shown in Table 1 below was used, and the other conditions were as in Example 1.
Various composite materials were prepared in the same manner as above.

These various physical properties are also listed in Table 1.

Claims (1)

[Claims] 1. A method for producing a composite material consisting of ceramics and metal, which comprises interposing copper or its alloy between a foam of nickel or its alloy and ceramics, and heating the mixture in an oxidizing atmosphere.