JPH048398B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method of 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, when using these methods, the bonding strength is weak and cannot withstand use under harsh conditions.
Alternatively, there are problems such as limited usage. For example, the excellent heat resistance of recent ceramics,
It has been proposed to utilize heat insulating properties to be applied to engines, etc., and one example is to join a ceramic molded body to the crown portion of a piston body made of aluminum alloy or the like. However, there is no known method for joining metal 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 Problems] The present invention uses a ceramic molded body having a porous portion when producing a joined body of ceramics and metal, and fills the pores of the porous portion of the ceramic molded body with metal. 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 formed. [Function] A porous part is provided in the ceramic molded body, and the metal part is provided so as to be integrated with the metal in the porous part, that is, to fill the pores of the porous part with the metal. As a result, a bonded body in which the ceramic molded body and the metal part are firmly integrated through the porous part can be obtained. [Example] Next, the method of the present invention will be explained 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 a solid ceramic part thereof, and 3 is a porous part thereof. The porous portion 3 is a continuous porous body;
is the hole. Next, as shown in FIG. 2, this ceramic molded body 1 is placed in a mold 10 and molten metal forged. That is, a molten metal 5 of a metal such as an aluminum alloy is injected and pressurized by a press 11 to fill the pores 4 of the porous portion 3 with the molten metal 5, and then removed from the mold 10 after cooling. In this way, a joined body as shown in FIG. 3 is obtained. In FIG. 3, reference numeral 6 indicates a metal-filled portion, and numeral 7 indicates a joint portion, and the joint portion 7 has a structure in which metal is filled into the pores 4 of the porous portion 3 of the ceramic molded body 1. 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, the bottom plate 2 made of plasterboard
An organic continuous porous body 23 which can be decomposed and removed later by heating is placed in a mold 20 consisting of a mold 1 and an outer shell 22, and a slurry 24 is poured thereon. In this case, the mold may be a closed type, and the slurry 24 may be injected under pressure. Then, the slurry enters into the continuous pores of the organic continuous porous body 23, and water is absorbed into the gypsum board. The remaining slurry 24 is deposited on the porous body 23. After the moisture has been absorbed, the outer shell is removed, the molded body integrated with the porous body 23 is taken out, heated at a low temperature (for example, 450 to 600°C) to decompose and remove the porous body 23, and then fired at a high temperature. Alternatively, a ceramic sintered body 1 consisting of a ceramic solid part 2 and a porous part 3 as shown in FIG. It will be done. The organic continuous porous material 23 is not particularly limited as long as it can be decomposed and removed by heating;
Because it can be easily decomposed and removed at a low temperature of about 500℃,
Resin foams, particularly polyurethane foams, are preferably used. Ceramic raw materials are appropriately selected from various oxides such as alumina, silica, zirconia, and yttria, nitrides such as silicon titride, borides such as zirconium boride, and carbides such as silicon carbide, 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, raw alumina, and yttoria is preferably used. If the porosity (volume %) of the porous part 3 of the ceramic molded body 1 is too low, the amount of metal intrusion is too small and the bonding strength decreases, and if the porosity is too high,
If the amount of ceramic in the porous portion 3 is too small, the bonding strength will also decrease. From this point of view, the porosity of the porous portion 3 is preferably in the range of 10 to 80%. In addition, in order to provide sufficient strength to both the ceramic skeleton structure in the porous part 3 of the ceramic molded body 1 and the metal skeleton structure formed by penetrating therein, the average pore diameter of the continuous pores 4 in the porous part 3 is The thickness is preferably about 1 μm to 10 mm. Thickness of porous part 3 (i.e. thickness of joint part 7)
Appropriately, it is about 1 to 50 mm. If the thickness is less than 1 mm, it is difficult to obtain the desired bonding strength;
Even if it exceeds mm, no improvement in bonding strength can be expected. Since the bonding in the bonded body in the present invention is mainly based on mechanical entanglement, the type of metal of the metal portion 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 metal 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. The bonded body obtained by the method of the present invention has high bonding strength even under harsh conditions,
Engine pistons, Rotzker arms, valves,
Suitable for use in valve seats, etc. FIG. 5 shows an example of application to an engine piston. In FIG. 5, the piston body 30
consists of a metal part 31 such as an aluminum alloy,
The crown part 32 is made of a ceramic part 33,
The metal part 31 and the ceramic part 33 are joined by the joining method of the present invention. Ceramics section 33
The thickness of the solid part is usually about 1 to 10 mm. Next, the method of the present invention will be explained with reference to Examples. Example 1 A polyurethane open foam with a thickness of 2 mm (85% porosity, average pore diameter
500 μm), and a casting slurry with the following composition was poured over it. Ingredients Part by weight Al ₂ 0 ₃ : 5.7 parts by weight Y ₂ 0 ₃ : 5.0 parts by weight Si ₃ N ₄ : 893.0 parts by weight Mixture 100 Polyvinyl alcohol 0.5 Ion exchange water 65.0 Cerner D-735 (Dispersion manufactured by Chukyo Yushi Co., Ltd.) 1.2 After standing for 30 minutes, the molded body was demolded, placed in a firing furnace and heated at 500℃ for 2 hours to decompose and remove the polyurethane open foam, and then placed in a nitrogen gas atmosphere (8.5Kg/cm ² ). It was sintered by heating at 1850°C for 4 hours. Thus, the porous part with a thickness of 2 mm (vacancy rate 75%,
A ceramic molded body consisting of a solid portion with an average pore diameter of 350 μm and a thickness of 2 mm was obtained. The thus obtained ceramic molded body was
Place it in a mold as shown in the figure, pour molten aluminum alloy (Cu 1.3%, Si 11-13%, balance Al) into it, press it with a press under a pressure of 1000 kg/cm ² for 1 minute, and after cooling, remove from the mold. A bonded body was obtained with the ceramic solid part having a thickness of 2 mm, the joint part having a thickness of 2 mm, and the metal solid part having a thickness of 2 mm. The swelling strength (Kg/mm ² ) of the obtained bonded 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 force 75 kg/cm ² , temperature 610°C,
The tensile strength was similarly measured for the bonded body obtained after 120 seconds). The results are shown in Table 1.

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

[Brief explanation of drawings]

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 an explanatory diagram showing a method for manufacturing a ceramic molded body used 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 drawing), 1: Ceramic molded body,
2: Ceramics solid part, 3: Porous part, 4: Continuous pores, 6: Metal solid part, 7: Joint part.

Claims (1)

[Claims] 1. When manufacturing a ceramic-metal bonded body, a ceramic molded body having a porous part is used, and a 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 characterized by the following.