JPS5841778A - Ceramic-metal composite structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Regarding.

Ceramics have superior properties that exceed conventional metal materials in terms of heat resistance, high rigidity, wear resistance, and corrosion resistance, so their use as structural materials has begun to be attempted in a wide range of fields. It has become.

When ceramics are actually used as a structural material, the entire structure is rarely made of ceramics, and is often composited with metals.

The biggest problem with such composite structures of ceramic members and metal members is that the ceramic members may be damaged due to stress caused by the difference in combustion coefficient of expansion between the two members due to temperature changes, or mechanical damage may occur from inside or outside. Metal members are elastically deformed in response to the force applied to them, avoiding stress concentration, whereas ceramics have high rigidity and are easily damaged by stress concentration.

As a measure to prevent damage to ceramics, it is possible to design the ceramic member so that the force applied to the ceramic member can be sufficiently dispersed by the metal member, or to provide a buffer layer between the ceramic member and the metal member.

However, there are few concrete plans for the configuration of a ceramic-metal composite structure from this point of view, and there is a method to provide a coating layer on the implanted part when combining a ceramic turbine blade and a metal disk ( Japanese Unexamined Patent Publication 1973-
No. 37009).

The present invention attempts to overcome the current situation by using a sintered metal having a specific relative density as a metal member.

Generally, sintered metals have a lower Young's modulus than molten metals of the same composition, and are known to cause large deformations even under small stress. By utilizing this, concentration of stress on the ceramic member can be avoided.

This characteristic of sintered metals is lost as their relative densities increase and their mechanical properties approach those of molten metals.

When we tested sintered metals with various relative densities in combination with ceramics, we found that the above effect had a significant criticality at a relative density of around 94%, and sintered metal members with relative densities below this level were ceramics, tuxedos, etc. Less chance of damaging parts (
On the other hand, it has been found that when using sintered metal parts with relative densities exceeding this limit, the stress concentration on the ceramic often reaches such an extent that it breaks.

Furthermore, it has been found that the limit of this relative density is approximately the same regardless of the type of metal, and is around the above-mentioned 94%. This is thought to be because the characteristics of a sintered metal are mainly controlled by its porosity and are not determined by the physical properties of the metal itself.

Therefore, the ceramic-metal composite structure of the present invention is first composed of a ceramic member and a metal member in contact with the ceramic member, and the metal member is made of a sintered material with a relative density of 94% or less. characterized by something. The metal member only needs to be a sintered metal having the above-mentioned relative density in the portion that is in contact with the ceramic member, and does not need to be entirely made of this sintered metal.

Therefore, the second type of ceramic-metal composite structure of the present invention is composed of a ceramic member and a metal member in contact with the ceramic member, and the metal member has a relative density of 94%.
It is characterized by being made of the following sintered material and the sintered material and/or ingot material with a relative density of 94% or less, and in contact with the ceramic member in the part of the sintered material with a relative density of 94% or less. shall be.

In such a composite structure in which a sintered metal with a relative density of 94% or less is provided as a so-called buffer layer, if the thickness of the layer is insufficient, stress concentration on the ceramic member will be incompletely prevented. . The required thickness varies depending on the shape and size of the composite structure, the relative density of the ceramic member, the relative density of the sintered metal, and the degree of stress generated.
However, experiments have revealed that in many cases, at least 1/2 of the thickness of the ceramic member is sufficient.

In either of the first and second types above, the temperature between the ceramic member and the metal member, and further.

When the metal members are composed of two or more types, the manner of contact between them is arbitrary. For example, mechanical methods such as bolting, press-fitting, shrink-fitting, adhesion, or chemical or physical methods such as welding, pressure welding, and diffusion bonding can be used.

In other words, the respective members may be joined to each other at the contact surfaces, or may simply be forced into contact with each other by another means.

Since the ceramic-metal composite structure of the present invention has good bonding between both members, the heat resistance, wear resistance, and corrosion resistance of ceramics can be utilized by utilizing the excellent mechanical properties of the metal member. . Therefore, the present invention
It can be applied to an extremely wide range of fields, including heat-resistant parts for heat engines, wear-resistant parts for valves and cams, and corrosion-resistant parts for chemical equipment.

Example 1 S I 3 with an inner diameter of 10 mm, an outer diameter of 30 MX, and a height of 10 mm.
N4 ordinary Akatsuki feeder ring, thickness 10mm x inner diameter 30mm
A double ring having the configuration shown in FIG. 1 was manufactured by press-fitting it into a ring of 808410 sintered body (relative density 90%) having an outer diameter of 50 WJ.

This was subjected to a heating-cooling cycle test in which it was kept in a furnace at 500°C in the atmosphere for 15 minutes, immediately put into water (about 25°C), then returned to the furnace after 2 minutes.

For comparison, a double ring of SUS 410 having the same shape as above but made of a material not according to the invention was also made and subjected to the same thermal cycle test.

The results are as follows.

(Present invention) Relative density 90% No change in fired crystal after 100 times Comparative example) Relative density 97% Ceramic fired crystal cracked in part after 38 times Casting (SCHI) 12 times 〃 Rolled material 8ri 〃 Implemented Example 2 In order to confirm the criticality of the relative density of sintered metal, double rings of the same material and configuration as in Example 1 were prepared, and the sintered relative densities of 5US410 were 88%, 92%, 96% and 98%.
%, three pieces of each were manufactured and the same heat cycle test was conducted.

The results are graphed as shown in Figure 2.

An upward arrow on the plot indicates that there is no red ledge in the heat cycle (100 times). When using 1-metal sintered metal with a relative density of 92%, the heat cycle resistance is extremely good, and when it reaches 96%, there are some that are equally good, but there are also those that deteriorate relatively easily, and 94%. We come to the conclusion that the limit is around %. The shaded area in the figure is a region of variation, which is thought to occur because the degree of defects present in the ceramic differs depending on the sample.

Example 3 The same materials and dimensions as in Example 1 were used, but the configuration was reversed, with S j 3 N 4 as shown in FIG.
A double ring with SUS 410 on the outside and SUS 410 on the inside was fabricated and a similar thermal cycle test was conducted.

The results are shown below.

(This invention) Relative density 90% Fired crystal that can be fed 100 times No change Comparative example) Relative density 97% 31 times ♀ Ceramic fired crystal with cracks in the part Casting (SCII 1) 10 times Rolled material
4 times Compared to the case of Example 1, although the conditions in this case are more severe in that more tensile stress is likely to be applied to the ceramic portion, excellent heat cycle resistance can be obtained according to the present invention.

Example 4.

A triple ring having the structure shown in FIG. 4 was manufactured by combining the following three types of rings.

○ Inner diameter 10 Mj x Outer diameter 30 x Height 10 + S
l 3 N 4 Normal sintered ring, ○ Inner diameter 30*a
5US304 sintered body of x outer diameter 42 mm x height 10 ip (
Relative density 90%) ring, and 5US304 rolled material ring with inner diameter 42 ms x outer diameter 62 w x height 10 fins.

On the other hand, when a heat cycle test similar to that in Example 1 was conducted, there was no change even after 100 cycles.

Example 5 From Example 4, the wall thickness of the SUS 304 sintered ring was made slightly smaller, and a triple ring having the configuration shown in FIG. 5 was manufactured using the following three combinations.

○ Inner diameter 10mm x outer diameter 301JIX height 10su*
S I 3 N 4 Normal sintered ring, ○ Inner diameter 3
5US304 sintered body (relative density 90%) ring with 0*sX outer diameter 38mm x height 10mm, and 5US304 rolled material ring with inner diameter 38111JX outer diameter 58mm x height 10mm+.

When we conducted a heating cycle test on 20 of these triple ring sunals, some of them did not change even after 100 cycles, while others cracked after about 80 cycles.Example 4
A slightly lower score was obtained compared to the . from this result,
It can be seen that the thickness of the sintered metal is preferably 1/2 or more of the thickness of the ceramic member.

Example 6 A capstan for a copper wire drawing machine having the structure shown in FIG. 6 was manufactured by combining sintered At203 and sintered 535C steel. This composite exhibited excellent wear resistance.

Example 7 The hot chamber (combustion chamber) of a vortex combustion type diesel engine was constructed using a chamber (combustion chamber) made entirely of 5UH661 sintered body, with the Si3N4 reaction sintered nozzle hole part as shown in Figure 7.
- As shown in Figure 8, a ceramic nozzle hole surrounded by a 5IJII661 sintered body is placed in a cast 5CH1 chamber through a casting K. This hot chamber has heat crack resistance comparable to that of conventional products made of heat-resistant Ni-based alloys.
It was able to exhibit the high temperature corrosion resistance that is an advantage of ceramics, and no melting loss was observed.

[Brief explanation of drawings]

Figure '1 shows a ceramic-sintered metal composite structure produced in Example 1 of the present invention, in which A is a plan view with half exposed and B is a sectional view along the axis of Tri5. ' Figure 2 shows the criticality of the relative density of sintered metal in a ceramic-sintered metal composite structure.
FIG. 2 is a diagram similar to FIG. 1 showing a ceramic-sintered metal composite structure manufactured in Example 3 of the present invention, in which A is a plan view with half exposed, and B is a cross-sectional view along the axis. Figure 4 shows the ceramics manufactured in Example 4 of the present invention.
It is a figure which shows a sintered metal composite structure, Comprising: A is a top view half exposed, B is a sectional view along an axis. FIG. 5 is a diagram showing a ceramic-sintered metal composite structure manufactured in Example 5 of the present invention, in which A is a plan view with half exposed, and B is a cross-sectional view along the axis. FIG. 6 shows a capstan for a copper wire drawing machine according to Example 6 of the present invention, with the middle half being a sectional view and the half being a plan view. FIG. 7 and FIG. 8 are both longitudinal sectional views showing a hot chamber of a vortex combustion type diesel engine manufactured from a ceramic-sintered metal composite. Patent Applicant: Daido Steel Co., Ltd. Agent, Patent Attorney Souo Suga

Claims (1)

[Claims] (+) A ceramic-metal composite structure comprising a ceramic member and a metal member in contact with the ceramic member, wherein the metal member is a sintered material with a relative density of 94% or less. . (2) Consists of a ceramic member and a metal member in contact with the ceramic member, with the metal member having a relative density of 94%.
Ceramics consisting of the following sintered material and a sintered material and/or ingot material having a relative density of over 94%, and in which a portion of the sintered material having a relative density of 94% or less is in contact with a ceramic member. -Metal composite structure. (3) The composite structure according to claim 2, wherein the thickness of the sintered material having a relative density of 94% or less is approximately 1/2 or more of the thickness of the ceramic member.