JPS586714B2 - Heat resistant joining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of joining two members, particularly a ceramic and a metal or ceramic.

For example, conventional methods for joining ceramics include (1) metal spraying (metallicon), (2) metallizing, in which a metal such as molybdenum is infiltrated into ceramics in a gas such as hydrogen, and (3) non-contact. A commonly used method is to form a metal surface on the ceramic surface by electrolytic plating or (4) baking silver or platinum paste, and then weld these metal surfaces to each other using solder or silver solder. has been done.

However, when the bonded portions formed by these methods are exposed to high temperatures in the air, they melt, oxidize, or deteriorate, resulting in a decrease in conductivity and strength.

The present invention has been made in view of these conventional drawbacks, and provides a method for simply joining ceramics together or joining ceramics and metals using a material that has sufficient heat resistance and conductivity.

That is, the present invention is a method for joining metal and ceramics or ceramics to each other, which involves mixing metal silicon powder or silicon alloy powder with a diameter of 300 μm or less with an organic binder, and temporarily bonding the two using the glue-like mixture. 1300～
This joining method includes heating and welding at a temperature of 1550C.

The metals and ceramics to be joined are not particularly limited.

The silicon alloy powder used includes, for example, Huekuchi silicon.

Examples of the organic binder include polyvinyl alcohol, methylcellulose, and starch, which are used in the form of an aqueous solution.

Further, the amount of the organic binder added is preferably 2 to 0.1% by weight based on the weight of the pasty mixture.

The above metal silicon or silicon alloy powder and organic binder are thoroughly mixed until they become paste-like.

If the diameter of the powder material exceeds 300 μm, the mixture will not form a smooth paste, making it difficult to temporarily bond parts to be joined, and is particularly unsuitable for joining minute parts or complicated parts.

The paste-like mixture thus obtained is then applied to the joining points of ceramic or metal parts to be joined.

For example, methods such as brush painting and screen printing can be used.

The members to be joined are temporarily adhered to each other by the adhesive force of the glue-like mixture.

Thereafter, it is preferable to dry the pasty mixture at a temperature of about 120° C. to harden it to some extent.

Finally, the parts to be joined temporarily bonded with the glue-like mixture were
Heat at a temperature of 0-1550C.

The organic binder is decomposed by this heating, and the silicon powder or silicon alloy powder is melted to join the two members to be joined.

According to this method, there is no need to form a single metal surface on the ceramic surface as in the conventional method.

Therefore, it is possible to join ceramics to each other or to join ceramics to metal much more easily than in the conventional method.

Since a smooth glue-like mixture is used as the bonding material, it is possible to bond even if the members to be bonded have minute or complicated shapes, and it is also possible to bond multiple parts at the same time.

Since the bonded area obtained by this method is a silicon welding layer, it has excellent heat resistance and good electrical conductivity.

Therefore, this joining method is suitable for joining a heating element in an igniter to a terminal.

In particular, it is suitable for joining the ultra-small silicon carbide heating element proposed in the patent application "Linear or band-shaped silicon carbide heating element" filed on December 24, 1972 by the present applicant to the terminal.

Example 1 20% by weight of a 3% aqueous solution of polyvinyl alcohol was added to 80% by weight of metallic silicon powder having a diameter of 149 μm, and the mixture was mixed for 1 hour using a stirring baler to obtain a pasty mixture.

The above paste-like mixture 2 was applied to a silicon carbide terminal 1 having a diameter of 3 mm and a length of 40 mm as shown in FIG.

Next, a separately prepared linear silicon carbide heating element 3 with a diameter of 1 mm and a length of 10 mm was temporarily bonded to the glue-like mixture 2 at a temperature of about 120°C.
It was dried.

This was buried in graphite powder and heated and welded at 1400°C.
Further, heat treatment was performed at 1000° C. in air.

The obtained product was used as a resistance heating type ignition element with a resistance value of 1KΩ as shown in FIG.

In FIG. 2, 4 is an insulator. Example 2 Example 1 except that heat welding was performed at 1400C in air
An ignition element having a resistance value of 2KΩ was obtained in the same manner as above.

This ignition element generated heat to 1000° C. under a load of 15 W, and although it was used for a long time, there were no abnormalities in the joints.

Example 3 The paste-like mixture used was 80% by weight and 1% by weight of second type silicone powder (silicon content 75-80%) with a diameter of 44 μm.
It consisted of 25% by weight of an aqueous polyvinyl alcohol solution.

The members to be joined are made by extrusion molding a kneaded material consisting of 30% by weight of silicon powder, 40% by weight of silicon dioxide, and 30% by weight of clay.
Ceramic tubes with different diameters made by firing at 300°C 5
,6.

The paste-like mixture was applied to both ends of the tube 5, which served as the heating element, and the tube 6, which served as the terminal, was inserted, and then dried at about 120°C.

This was heated in air at 1380°C to weld.

The obtained product could be used as a heating element with a resistance value of 33Ω by attaching the electrode 7.

Example 4 The paste-like mixture used was 80% of metallic silicon powder with a diameter of 74 μm.
% by weight and 20% by weight of a 3% polyvinyl alcohol aqueous solution.

On the other hand, 95% by weight of barium stannate and 5% by weight of antimony trioxide
A ceramic resistor was produced by adding 30% by weight of pottery stone to the mixture, extruding the kneaded product into a rod shape with a diameter of 3 mm and a length of 50 mm, and firing it at 1300°C.

A tungsten wire 9 having a diameter of 0.5 mm was wound around this rod-shaped resistor 8 as shown in FIG. 4, and the paste-like kneaded material was applied to the wound portion.

After drying at about 120°C, it was heated at 1400°C in an argon gas to fuse.

A heating element with a resistance value of 5.5 KΩ was obtained.

[Brief explanation of the drawing]

1 to 4 are perspective views for explaining each specific example to which this method is applied. DESCRIPTION OF SYMBOLS 1...Silicon carbide terminal, 2...Glue mixture, 3...Silicon carbide heating element, 5...Ceramic tubular heating element, 6... ... Ceramic tubular terminal, 8 ... Ceramic resistor, 9 ...
・Tungsten wire.

Claims (1)

[Claims] 1 In a method for joining metal and ceramics or ceramics to each other, a metal silicon powder or silicon alloy powder with a diameter of 300 μm or less is mixed with an organic binder, and the two are temporarily bonded using the glue-like mixture, and the temperature is 1300 to 1550°C.
The above joining method includes heating and welding at a temperature of .