JPS60180658A - Production of ceramic-metal composite body - Google Patents

Abstract

PURPOSE:To produce a ceramic-metal composite body having excellent resistance to thermal impact by coating a metal having specific porosity around a ceramic core material and converging said metal to an oxide, nitride, carbide, silicide, boride, sulfide, etc. then subjecting the same to insert-casting into a metal. CONSTITUTION:A metal such as Al, Zr, Si, Cr, Ti, Mo, etc. is thermally sprayed by gaseous acetylene/oxygen onto the surface of a core material 1 made of ceramics such as alumina, zirconia, magnesia silicate, silicon nitride, titanium silicide, Sialon, etc. or the material 1 is enveloped by said metallic powder and is sintered to form a metallic layer having 5-85% porosity to about 0.5mm. thickness. Such porous metallic layer is chemically treated to form a metallic compd. layer 11 composed of one or >=2 kinds among the oxide, nitride, carbide, silicide, boride and sulfide of said metal. The core material is then put into a casting mold and a molten metal such as ''Inconel'' or the like is poured into the mold to form insert-casting layers 2, 3 having respectively about 5mm. wall thickness. The composite body which obviates cracking of the ceramic core material 1 by thermal impact is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for manufacturing ceramic-metal composites.

For example, the most typical method for manufacturing ceramic-metal composites used in engine parts is casting metal around a ceramic core material. This casting technique has the risk that the ceramic core material may crack due to thermal shock when it comes into contact with high-temperature molten metal, reducing the strength of the product composite.

One solution to this problem is to use the same or different types of ceramics, metals, etc. on the surface of the ceramic core material.
Alternatively, it is possible to provide a protective layer made of a composite of metal and ceramics.

As a means of forming such a protective layer, the applicant previously established a thermal spraying technique and disclosed it in the publication.

Subsequent research has shown that a protective layer made of ceramic by forming a metal coating layer by thermal spraying or other means and then chemically converting this layer into ceramic has good results in mitigating thermal shock during casting. I have found something to offer, so I would like to propose it here.

The method for manufacturing a ceramic-metal composite of the present invention is a method for manufacturing a ceramic-metal composite by casting a ceramic core l with metal, in which a metal layer with a porosity of 5% or more is formed on the surface of the ceramic core material. After forming and converting most of this layer into oxide, nitride, carbide, silicide, boride, or sulfide, or a mixture or composite compound of two or more of these, it is cast with metal. It is characterized by

Ceramic core materials that can be used in the present invention include alumina (A qO3')1. Zirconia (ZrO2) Magnesia Silicate (2Mgo・Si 02, MgO-8
i02), magnesium alumino silicate (2M
O0・2A203・5Si O2) Silicon nitride (Si
3N4), Silicon oxynitride (Si 9ON9), Titanium nitride (TiN), Sialon, Silicon carbide (SiC)
, titanium boride (TiB2), molybdenum silicide (MO
8iz), etc., and the manufacturing method and form thereof are arbitrary, such as sintered bodies, single crystals, those produced by physical and chemical precipitation methods, and those of glass type obtained by melting methods.

The coating metal that is first formed on the surface of this ceramic layer is selected depending on the compound that is to be chemically converted and produced. Representative ones are Ami, Zr,
3i, Cr, Ti and MO.

The method of forming these and other metal coatings can also be selected depending on the material.

The most common method is thermal spraying, but a ceramic core material may also be wrapped in metal powder and sintered. Alternatively, the metal sintered body or the foamed metal body can be integrated by core shrink fitting or press fitting. In order to improve the adhesion between the core material and the metal layer, it is preferable to metalize the surface of the core material in advance.

Regardless of which method is used, the metal W layer formed on the surface of the ceramic core material must have a porosity of 5% or more. This is necessary so that the reactants can penetrate into the interior of the coating when the metal is converted into various ceramic compounds in the next step. The larger the porosity, the easier the conversion, but if the porosity is too large, the strength of the resulting protective layer will be low, impairing the bonding between the core and the cast metal.
The upper limit of porosity is usually about 85%. The optimum porosity should be determined experimentally in each case, since it depends on conditions such as the type of metal and the compound formed by its conversion.

The compound produced by the conversion of the coated metal is selected so as to be most effective in protecting the ceramic core material.
The most common point of view is to alleviate the thermal shock caused by the molten metal, so it is desirable to have a material with high thermal insulation properties, that is, low thermal conductivity. In addition to the preheating conditions for Must be. When composite products are used under thermal cycling conditions,
It is also necessary to consider the difference in thermal WJ3DI rate between the protective layer and the core material.

The chemical conversion means for forming a protective layer from a metal coating is as follows.

Oxidation is caused by heating in air or an oxidizing atmosphere.
Easy to do. Nitriding, carbonizing and sulfiding are performed in a gas that provides a nitriding, carbonizing and sulfiding atmosphere, respectively.
It is carried out in a liquid or by burying it in a powder and heating it. Silicification is achieved by contacting with 3i steam or molten metal. Boriding is possible by heating with a boriding gas such as diborane, or a boron-containing compound. By performing these treatments simultaneously or sequentially, a protective layer containing a mixture of two or more compounds or a composite compound can be formed.

The conversion of the metal must be carried out in such a way that the majority of it becomes a compound. If the conversion rate is low (for example, more than 20% of unreacted metal remains), the thermal conductivity of the protective layer will not decrease as expected and will not meet the purpose, or the residual metal will It may react with the molten metal being cast.

The effect of the protective layer depends on its thickness, porosity, adhesion to the core material, etc., but generally speaking, the higher the porosity and the thicker the thickness, the greater the effect as long as the PA is high in terms of heat insulation. In most cases, the porosity ranges from 5 to 40%, and the thickness ranges from 0.
Approximately 1 to 211 is appropriate. As for mechanical strength, the protective layer cannot be said to be strong, so if it is too thick, the core material and surrounding metal may easily peel off, which is not preferable.

The ceramic core protected according to the invention is cast into a composite with metal by known techniques.

Hereinafter, the present invention will be specifically explained with reference to Examples.

A ceramic-metal composite 10 having the structure shown in the drawings was manufactured.

Outer box 30i made of Al2O3 as ceramic core material 1
A cylinder having an inner diameter of 241 Rm (therefore, a wall thickness of 311 Il) and a length of 3 Q mm was prepared, and a dimple layer having a thickness of 0.5+ am was formed on the surface of the cylinder by spraying acetylene-oxygen gas. Its porosity is about 20%.

By heating this in the air at 580° C. for 5 hours, the A1 layer was oxidized to form the A2203 layer 11.

Place the above A312 (ceramic core material 1, which is a cylinder with an Is protective layer 11 and a diameter of 203, in a mold, and
The inner metal layer 2 and the outer metal layer 3 are preheated to 1,450 degrees Celsius and molten Inconel 713C is poured into the inner metal layer 2 and the outer metal layer 3 to a thickness of 5. Qllll was formed and solidified by cooling. No cracks were observed in the A5L203 core material 1 of the obtained composite 10.

For comparison, when the AuzOs core material was directly cast without forming a protective layer, a large number of very small cracks occurred throughout the core material.

The same Adanzoa core material as in Example 1 was used, and its surface was coated with various metals using various coating methods, which were further converted using various chemical methods to form a protective layer. .

I performed a ritual. No cracking occurred in any of the product composites.

The coating metal and its application method, coating thickness and porosity, conversion method, and thickness of the conversion product and protective layer containing it are summarized in the table.

[Brief explanation of the drawing]

The drawings show ceramics manufactured according to an embodiment of the present invention.
The structure of the metal composite is shown - the left side is a longitudinal cross-sectional view and the right side is a half cross-sectional view. 1... Ceramic core material 2... Inner metal layer 3... Outer metal layer 10... Ceramic-metal composite 11... Protective layer Patent applicant Jindo Special Steel Co., Ltd. Representative Patent attorney Takeo Suga Procedural Techniques (Method) June 15, 1980 Patent Application No. 35841 of 1982 2, Title of Invention Method for Manufacturing Ceramic-Metal Composite 3, Matters to be Amended 4'1 -What kind of relationship Patent applicant address: 66 Kawide, Hoshizaki-cho, Minami-ku, Nagoya, Aichi Prefecture Name
(371) Daido Special Steel Co., Ltd. Representative Aki 1) Masaya 4, Agent, 104 Address Yasuda Real Estate Tsukiji Pill e, 2-15-14 Tsukiji, Chuo-ku, Tokyo (541) 3792 Shipping date 1982
May 29, 2016, 6, Subject of amendment (1) As shown in the page drawing of page 8, lines 1-2 of the specification...
・Manufactured. '' is deleted and the following sentence is added in its place: [A ceramic-metal composite 10 having a structure whose cross section is shown in FIG. 1 and whose longitudinal section is shown in FIG. 2 was manufactured.'' (2) On page 11, lines 2 to 4, the sentence "The drawing is..." is deleted and the following sentence is added in its place. 1 shows ceramics manufactured according to an embodiment of the present invention.
The structure of the metal composite is shown, with FIG. 1 being a half cross-sectional view, and FIG. 2 being a longitudinal cross-sectional view. (3) Replace the drawing with the attached one.

Claims (1)

[Claims] (1) In a method of manufacturing a ceramic-metal composite by casting a ceramic core material with metal, a metal layer with a porosity of 5% or more is formed on the surface of the ceramic core material, and most of the metal in this layer is , oxides, nitrides, carbides, silicides. A manufacturing method characterized by converting the material into a boride, a sulfide, or a mixture or composite compound of two or more thereof, and then casting the product into a metal.