JPS59217681A - Method of bonding ceramic members - 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 The present invention relates to a method for joining ceramic members.

As a method of joining a ceramic member to a member to be joined,
Conventionally, bonding using a bonding agent has been considered. However, in this method of using a bonding agent, since the purpose is to semi-permanently bond members together, it is extremely difficult to select a bonding agent and a bonding method. For example, when bonding a ceramic member to the piston crown of an internal combustion engine to increase combustion temperature, due to the difference in thermal expansion coefficient between the steel piston crown and the ceramic member, joining with a bonding agent may cause peeling or damage to the ceramic member. There was a problem, and it was impossible to select a bonding agent or a bonding method to eliminate this problem.

The present invention solves the above-mentioned conventional drawbacks, and allows ceramic members to be properly maintained without peeling or damage even when the ceramic members are exposed to high temperatures (e.g., 800°C or higher) during use. An object of the present invention is to provide a method for joining ceramic members that can be joined to members to be joined.

In order to achieve the above object, the method for joining ceramic members of the present invention involves interposing a thin layer of a low melting point metal at the interface between the ceramic member and the member to be joined, and using this thin layer to bond the ceramic member to the member to be joined. This is a configuration for joining.

According to this configuration, when the ceramic member is exposed to high temperature during use, the ceramic member and the member to be joined are bonded well by the surface tension of the liquid low-melting metal, atmospheric pressure, or both, and therefore the ceramic member Thermal expansion of the ceramic member is almost unrestricted, and no peeling or damage to the ceramic member occurs.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Fig. 1, (1) is a ceramic member, (2) is a member to be joined to which the ceramic member (1) is joined, and the interface between the top surface of the member to be joined (2) and the ceramic member (1). A thin layer (3) of a low melting point metal is interposed therein. This is a ceramic member (1) with a thin layer (3) of low melting point metal formed on the top surface of the member (2) to be joined.
) are inserted and fitted together, and as a method for forming the thin layer (3), it is suitable to use a thin film created by chemical vapor deposition (CVD') or rapid solidification.

The low melting point metal constituting the thin layer (3) liquefies at the temperature of the ceramic member (1) when the member to be joined (2) to which the ceramic member (1) is joined is used.
Select a material that has excellent wettability for the ceramic member (2) when liquefied. As this material, a material containing boron, phosphorus, carbon, silicon, germanium, etc. whose melting point can be easily controlled, or a brazing material is suitable.

The thin layer (3) of the low melting point metal does not exhibit bonding force in a solid state, but when it is liquefied, the gas phase part is completely eliminated at the interface between the ceramic member (1) and the member to be joined (2). Further, since surface tension is generated, the ceramic member (1) and the member to be joined (2) are well joined by atmospheric pressure, surface tension, or both. At this time, since the thermal expansion of the ceramic member (1) is hardly restrained, the ceramic member (1) will not be peeled off or damaged.

The thickness of R@(3) is related to the surface roughness of the ceramic member (1) and the member to be joined (2) that are in contact with each other via the thin layer (3), but is preferably about 20 to 100 μm. In other words, if the thickness of the thin layer (3) is too thin, even if it liquefies, the top surface of the member to be joined (2) and the ceramic member (1)
If the layer thickness is 20 μm or more, it becomes possible to completely cover the interface with the liquid and exhibit bonding force.

Even if the thickness is further increased, the effect remains the same, but 100μ
If it exceeds m, the contribution of atmospheric pressure and surface tension decreases, so the bonding force decreases.

The bonding by the thin layer (3) is the ceramic member (1)
Although it is sufficiently effective against the force in the direction of peeling off the member to be joined (2), it is weak in the shear direction, so the thin layer (3)
It is preferable to devise the shapes of the ceramic member (1) and the member to be joined (2) so that such a force does not act on them, or other forces that resist this force act on them. In other words, the shape shown in Fig. 2 (A) is inappropriate, and the shape shown in Fig. 2 ([3) (C)]
) is preferably provided with a protruding skirt portion (1a) to prevent shearing force from acting on the RWE (3). In addition, in the case of continuous use for a long time, it is possible that some liquefied low-melting metal may leak out, but in order to deal with this, the 27th J (
As in C), it is most preferable to make the skirt portion (1a) sufficiently long so that the liquefied low melting point metal is re-assimilated within the range of the skirt portion (1a). Also, when used upside down compared to the state shown in Figure 2,
Since the weight of the ceramic member (1) acts as a peeling force, it is preferable to reduce the weight of the ceramic member (1).

Figure 3 shows an example in which a cast steel piston crown body is used as the member to be joined (2), and a ceramic member (1) is joined to this piston crown body with a thin layer (3) of low melting point metal. If such a piston crown is used, the combustion temperature can be raised to improve combustion efficiency, and there is no fear of peeling or damage to the ceramic member (1).

[Specific Example] As shown in FIG. 4, the inner diameter is 17. Omttt, height 2
5〃I shoulder.

A ceramic member (1) made of SiC ceramics with a thickness of 2 silk, and an outer 1. At the interface with the top surface of the member to be joined (2) made of Si3N4 ceramics with a diameter of 16.95 mm, a thin film made of nickel containing 7 wt% phosphorus and 8 wt% boron and having a thickness of 50 μm was prepared by a rapid solidification method. With layer (3) interposed, the vicinity of thin layer (3) is 900°
The member to be joined (2) was moved up and down at a rate of 20 times/min under a temperature condition of C. In this case, ceramic member (1)
It could be used for 470 hours without any peeling. Further, when the material of the thin layer (3) was nickel containing 5 wt% phosphorus and the temperature condition was such that the temperature near the thin layer (3) was 1100°C, it could be used for 600 hours. Also, the member to be joined (2
) when using AjhO:i-based ceramics,
In addition, in order to prevent reaction with liquefied low melting point metal, 5i02 was chemically vapor deposited on the top surface to a thickness of 7 μsn.
Good results were also obtained when the member to be joined (2) made of a low alloy was used.

As explained above, according to the present invention, it is possible to obtain a good fit without peeling or damage even when the ceramic member becomes hot during use.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a ceramic member and a member to be joined by a joining method according to an embodiment of the present invention, FIG. 2 is a cross-sectional view illustrating the shapes of the ceramic member and a member to be joined,
FIG. 3 is a cross-sectional view of a piston crown using a joining method according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view showing a specific embodiment. (1) Ceramic components, (2) Parts to be joined, (3) Agent Yoshihiro Morimoto

Claims (1)

[Claims] 1. A method for joining ceramic members, characterized in that a thin layer of a low-melting point metal is interposed at the interface between the ceramic member and the member to be joined, and the thin layer is used to join the ceramic member to the member to be joined.