JPH01212283A - Production of joined body of ceramics and metal - Google Patents

Abstract

PURPOSE:To obtain the joined body which is adequate for a piston of an engine, etc., and has the high joint strength to ceramics even under severe conditions by pouring a molten metal to a ceramics molding having a porous part in such a manner as to pack the pores of the porous part, thereby integrating the molding and the metal. CONSTITUTION:The open-cellular ceramics molding 1 consisting of the porous part 3 and the solid ceramics part 2 is housed in a mold 10 and the melt 5 of the desired metal or alloy such as Al alloy is injected therein and is pressurized by a press 11 to pack the metal 5 into the pores 4 of the porous part 3; thereafter, the molding is taken out of the mold 10 and is cooled. The solid metal part 6 and the solid ceramics part 2 are thus securely joined by the joint part consisting of the metal or alloy packed in the pores 4 of the porous part 3 of the ceramics molding 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a ceramic-metal bonded body.

[Prior Art/Problems to be Solved by the Invention] Conventionally, methods such as adhesive bonding, metallization, and fusion bonding have been used to bond ceramics and metals.

However, it has been reported that these methods have low bonding strength, cannot withstand use under harsh conditions, or have limited applications.

For example, it has recently been proposed to utilize ceramics' excellent heat resistance and heat insulation properties to apply them to engines, etc. One example is joining a ceramic molded body to the crown of a piston body made of aluminum alloy. can give.

However, there is no known method for joining metals and ceramics that can withstand practical use under harsh conditions, such as in the case of pistons in engines.

In view of the above points, the present invention aims to provide a ceramic-metal bonded body that has excellent bonding strength even under severe usage conditions.

[Means for Solving the Problem] The present invention uses a ceramic molded body that covers a porous part when producing a joined body of ceramics and metal, and injects metal into the pores of the porous part in the ceramic molded body. The present invention relates to a method for producing a joined body of ceramics and metal, characterized in that a metal part is integrally provided so as to be filled with the metal part.

[Function] By providing a porous part on the ceramic molded body and integrating with metal in the porous part, that is, by providing a metal part so that the pores of the porous part are filled with metal. , a joined body in which the ceramic molded body and the metal part are firmly integrated in the porous part is obtained.

[Example] Next, the present invention will be explained in detail based on the drawings.

FIGS. 1 to 3 are explanatory diagrams showing one embodiment of the method of the present invention in the order of steps.

In FIG. 1, (1) is a ceramic molded body,
(2) is the ceramic solid part, and (3) is the porous part. The porous part (3) is a continuous porous body, and (4)
is the hole.

Next, as shown in Fig. 2, this ceramic molded body (
1) is placed in a mold (goods) and forged with molten metal. That is, molten metal (5) such as aluminum alloy is injected, pressurized by press 01), and the molten metal (5) is poured into the pores (3) of the porous part (3).
4) Fill the container, and then remove from the mold η after cooling.

In this way, a zygote as shown in FIG. 3 is obtained. In Fig. 3, (6) is a solid metal part, (7) is a joint part, and in the joint part (7), the metal is in the pores (4) of the porous part (3) of the ceramic molded body (1). It has a filled structure. Such a structure of the joint portion (7) allows the solid metal portion (6) and the ceramic molded body (1) to be firmly joined.

Although the method for manufacturing the ceramic molded body (1) having the porous portion (3) is not particularly limited, a method based on a slurry casting method will be described here.

The slurry casting method for ceramics involves injecting slurry made of ceramic raw materials, binders, and a medium such as water into an absorptive mold such as a plaster mold, and allowing the mold to absorb moisture to form the desired molded product. It is.

As shown in Figure 4, an organic continuous porous material that can be decomposed and removed by heating is placed in the mold head made of a plasterboard bottom plate (2TJ) and an outer shell, and slurry Q4 is poured over it. The mold may be a closed type, and the slurry Q4 may be injected under pressure.The slurry then enters into the continuous pores of the organic continuous porous body □, and the water is absorbed by the plaster plate.

The remaining slurry Q4 is deposited on the porous body.

After the moisture has been absorbed, the outer shell is removed, the molded body integrated with the porous body is taken out, and heated at a low temperature (for example, 450~
By heating the porous body at 00°C to decompose and remove it, and then firing it at a high temperature, or by directly firing it to decompose and remove the porous body and sinter it at the same time, it is possible to create a ceramic material as shown in Figure 1. The ceramic sintered body (1) consisting of a portion (2) and a porous portion (3) is replaced.

The organic continuous porous material is not particularly limited as long as it can be decomposed and removed by heating, but resin foams, particularly polyurethane foams, are preferably used because they can be easily decomposed and removed at a low temperature of about 500°C.

Ceramic raw materials are appropriately selected from various alumina, silica, zirconia, oxides such as yttria, nitrides such as silicon nitride, borides such as zirconium boride, carbides such as silicon carbide, etc., depending on the purpose of the joined body. Conventional binders, dispersants, etc. are also used.

When used for the crown portion of a piston in an engine, a ceramic raw material having a composition consisting of silicon nitride, alumina, and yttoria is preferably used.

The porosity of the porous part (3) of the ceramic molded body (1) (
If the porosity (volume %) is too low, the amount of metal intrusion is too small and the bonding strength decreases, and if the porosity is too high, the amount of ceramic in the porous portion (3) is too small and the bonding strength also decreases. From this point of view, the porosity of the porous part (3) is 10 to 80%.
A range of is preferred.

In addition, from the viewpoint of providing sufficient strength to both the ceramic marrow structure in the porous part (3) of the ceramic molded body (1) and the metal marrow structure formed by penetrating therein, the continuous The average pore diameter of the pores (4) is preferably about 1-10 arms.

Thickness of porous part (3) (i.e. thickness of joint part (7))
Approximately 1 to 50 degrees is appropriate. If the thickness is less than 1111 mm, it is difficult to achieve the desired bonding strength;
Even if it exceeds (2), no improvement in bonding strength can be expected.

Since the joining in the joined body in the present invention is mainly based on mechanical entanglement, the type of metal of the metal part (6) is not particularly limited, and may be appropriately selected depending on the application. For example, for pistons in engines, aluminum alloys, cast iron, etc. are used.

In the above, a case has been described in which a porous ceramic body and a metal are joined by molten metal forging, but the invention is not limited to this. It is also possible to adopt a method of manufacturing a bonded body by stacking the molded bodies and heating and melting the side of the metal molded body in contact with the porous part (3) to impregnate the porous part (3).

Since the joined body obtained by the method of the present invention has high joint strength even under severe conditions, it is suitably used for engine pistons, rocker arms, valves, valve seats, etc.

FIG. 5 shows an example of application to an engine piston. In Fig. 5, the piston body ■ consists of a metal part (31) such as an aluminum alloy, and a crown part (32).
consists of a ceramic part (33), and the metal part (31) and the ceramic part (33) are joined by the joining method of the present invention. The thickness of the ceramic portion (33) (solid portion) is usually about 1 to 101111 mm.

Next, the present invention will be explained in detail with reference to Examples.

Example 1 A polyurethane open foam (porosity 85%, average pore diameter 500ρ) with a thickness of 2 mm was placed in the bottom of the plaster mold shown in Figure 4, and a casting slurry with the following composition was poured over it. is.

Ingredients Parts by weight Polyvinyl alcohol 0.5 Ion exchange water B5.0 Cerna D-7
35 (Dispersant manufactured by Middle East Yushi ■) 1. After being left for 30 minutes, the molded body was removed from the mold, placed in a firing furnace and heated at 500°C for 2 hours to decompose and remove the polyurethane continuous foam, and then placed in a nitrogen gas atmosphere. It was sintered by heating at 1850° C. for 4 hours at 8.5 kg/cj. In this way, a ceramic molded body consisting of a porous part with a thickness of 2 mm (porosity: 75%, average pore diameter of 350 ρ) and a solid part with a thickness of 2 mm was obtained.

The ceramic molded body thus obtained is placed in a mold as shown in Figure 2, and then an aluminum alloy (Cu
1.3%, 3111 to 13%, balance N) was poured into the molten metal, pressed under a pressure of 1000 kg/ad for 1 minute, cooled, and removed from the mold.The thickness of the ceramic solid part was 21.
A joined body was obtained in which the thickness of the 111% joint part was 211° and the thickness of the metal solid part was 2 fins.

The tensile strength (kg/nvli) of the obtained joined body was measured. For comparison, an aluminum molded body and a ceramic molded body mainly composed of silicon nitride were bonded by solid reaction bonding (pressure cuff 5 kg/d, temperature 610°C, time 12
The tensile strength of the bonded body obtained by 0 seconds) was also measured in the same manner.

The results are shown in Table 1.

Table 1 [Effects of the Invention] The bonded body according to the present invention has a high bonding strength between ceramic and metal under severe conditions, so it can be suitably applied to pistons in engines.

[Brief explanation of the drawing]

Figures 1 to 3 are explanatory diagrams showing an example of the method of the present invention in the order of steps, Figure 4 is an explanatory diagram showing a method for producing a ceramic molded body used in the present invention, and Figure 5 is a joined body in the present invention. FIG. 2 is a schematic partial cross-sectional view showing an example in which the method is applied to a piston of an engine. (Main symbols in the drawings) (1): Ceramic molded body (2): Ceramic solid part (3): Porous part (4): Continuous pore (6): Metal solid part (7): Joint part Fig. 1

Claims (1)

[Claims] 1. When manufacturing a ceramic-metal bonded body, a ceramic molded body having a porous part is used, and the metal part is integrally provided in the ceramic molded body so that the pores of the porous part are filled with metal. A method for producing a joined body of ceramics and metal.