JPS60141504A - Manufacture of ceramic part - 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 [Industrial Field of Application] The present invention relates to a method for manufacturing structural ceramic parts by injection molding.

[Prior art]

In recent years, ceramic parts have begun to be widely used in various sedentary work fields, taking advantage of their superior heat resistance, wear resistance, corrosion resistance, etc., compared to metal parts. The manufacturing method is to melt and knead ceramic powder and an organic binder whose main components are all thermoplastic resins, and then form this kneaded product into pellets to form a side fat composition for molding (hereinafter referred to as ceramic resin). The desired molded product is made by injection molding into a mold in the same way as injection molding of thermoplastic resin, and this molded product is heated to the decomposition temperature of the compounded resin to decompose and remove the resin (referred to as degreasing). ), and then the ceramic is fired at 9A axis temperature to form a sintered body.

In this way, ceramic injection molding is carried out by utilizing the thermoplasticity of a homogeneously mixed resin, but the resin used as a binder must have an appropriate degree of decay at the molding temperature and be easily molded as a ceramic resin. It won't happen. In addition, since a single resin will decompose into a steep slope at a single temperature, it is generally helpful to use a mixture of two or more resins when selecting the resin.

1) When injection molding ceramic resin into a mold to make a molded product with a complex shape such as an automobile industrial part, the difference in wall thickness of each part causes temperature distribution, pressure distribution, etc. The flow characteristics of the ceramic and ceramic *i fats are not necessarily uniform, leaving internal distortions during the cooling process after injection molding, and causing peeling and cracking sounds on the next surface of the molded product during the degreasing and firing process. Defective sounds often occur. Therefore, in order to make the pressure distribution inside the mold uniform, complicated techniques are required to fully control the molding temperature, and special techniques are required for kneading the ceramic and resin.
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Furthermore, in order to remove the binder from the molded product, the molded product is heated gradually in a binder-filled atmosphere to prevent it from oxidizing. No matter how careful you are in manufacturing parts, you are often plagued by slight defects.

As a means of reducing the above-mentioned complexity, a method has been developed in which a molded product is divided into parts at appropriate positions, and the parts are assembled into one piece. For example, a method has been proposed in which a bonding material mainly composed of fine powders of silicon carbide and silicon nitride is applied to the bonding surfaces of silicon carbide sintered bodies, and then the bonding material is pressed using a Shima-on pressure. There are problems such as the preparation is labor-intensive and the heating and oral pressure devices are cumbersome.

[Purpose of Koukou]

It is an object of the present invention to provide a method for manufacturing ceramic parts of a compact shape without using a bonding material, which is complicated by the bonding process.

[Senior brother Akira]

The Ministry of the Invention has discovered that it is possible to obtain ceramic parts with high cohesive strength by heat-pressing the joining parts of members molded into a shape that can be joined together under ultra-high hydrostatic pressure. The method for manufacturing ceramic parts of the invention is as follows: (1) Using a ceramic 41fJJ1m acid whose main components are ceramic powder, thermoplastic resin, and organic binder, the Hf desired molded body has a completely divided shape, and mechanically (1) a step of assembling and joining the above-mentioned members; (2) a step of liquid-tightly sealing at least the joint portion of the joined molded body; (2) a step of molding the above-mentioned molded body into the molded body; The softening of the IM during the summer or the process of pressurizing the entire M joint by hydrostatic pressure in a liquid at a still higher temperature; ■ The process of heating and removing the organic components of the integrated form; ■ The process of heating and removing the organic components of the form The process of firing the degreased body obtained in the step of (+-% image) The ceramics used in the present invention include silicon carbide (8iL:), silicon carbide (81sN4), and Made of aluminum (AIN), sialon ceramics, or a mixture thereof.

Thermogenic resins used as commercially available binders include polypropylene, polyethylene, atactic polypropylene, and olefinic polymers or copolymers in the form of ethylene-vinyl acetate copolymers, which have good flowability and are preferred. Conventional tjJ9ii agents such as diethyl phthalate and lubricants such as stearic acid, paraffin, etc. are used to increase the properties.

A member obtained as an injection molded product by a conventional method from these ceramic side force a-assemblies has a shape that can generate a mechanical bonding force in the mutually assembled parts.

To join these members together, the bonding force of the organic binder described above is used, so a bonding force of 100 to 200 degrees is used.
'Y atmospheric pressure, which is an ultra-flat pressure, is necessary. Furthermore, hydrostatic pressure is required to uniformly transmit pressure to joints having complicated shapes.

Therefore, if the entire periphery of the joint is heated thoroughly in a neutral pressure medium to prevent the pressurized liquid from entering the joint, the resin at the joint will fuse and the joint surfaces will be pressed together. Except for this,
Since the molded body is integrally under hydrostatic pressure, it does not deform.

The thus obtained resistive body becomes a highly integrated ceramic city through a normal sintering process.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 This ceramic was prepared by mixing silicon nitride powder with a half YJ column diameter of 1 μm and mixing Y2O as a sintering aid and MgAl□04 powder in an amount of 5 to 5, respectively. Ethylene-vinyl acetate co-polymerized raw material (
EVA) 16 layers of gold, 2 mk% of paraffin, and 1 layer of stearic acid were added and mixed in a bath at about 180°C. This mixture was directly extruded using a vibration-damping extruder to form pellets with a length of approximately 5 mm, and was used as a raw material for injection molding. Injection molding was performed at 180° C. and 900 ky/− to obtain wing portion 1 and 41] portion 2 as members. As shown in FIG. 2, they are assembled at the joint 3 and mechanically connected to form a molded body (turbine rotor) 4.
The entire area is sealed liquid-tight. The above-mentioned sealing is carried out by repeating dipping and drying with dispersed silicone rubber until a rubber film 5 of exceptional thickness is obtained.

The sol molded body 4 is placed in a pressure vessel containing silicone oil as the pressure medium, heated to a temperature at which the molded body 4 softens (10°C to 12°C), and heated to a temperature of 2,000 to 4,000 °C.
Pressure was applied for several minutes at atmospheric pressure. Next, the molded body 4 was taken out from the pressure vessel, the rubber film 5 was peeled off, and the molded body 4 was placed in an oven in a nitrogen stream at a heating rate of 94°C per hour to 450°C, and the organic binder was separated. It was removed. Furthermore, after firing at 1800° C. for 4 hours in a nitrogen stream to form a ceramic city, all X-ray images of the bonded portion 6 showed that fc was completely bonded and no missing LIII8+ was observed.

Example 2: Is the third worst thing to implement? 1111+ m diagram <c> and cross-sectional view (d) of the shaft part 2 in the case where the shape of the convex s1a of the wing part 1 of l11 is made cross-shaped, and the cross-shaped concave part 2af for fitting into the convex s1a is shown. <This is a provision. Therefore, it is possible to maintain the maximum stress of 1.11 in response to the screw damage caused by the rotation of the small gun in actual use. In this way, the shape of the connecting part B can be changed freely, and it is also possible to make it into a threaded structure.

Test Examples For the turbine rotors of Example 1 and Example 2,
An O'co hot spin test was conducted, and the turbine rotor of Example 1 did not cause any cracks or cracks even at 180, 00 Or, p, and m, and the turbine rotor of Example 1 had a performance of 200.0.
00r, p, m without any cracks or cracks.

〔Effect of the invention〕

As described above, according to the present invention, a ceramic component having a double-silver shape can be manufactured from members having a simple shape, so the process is simpler than the conventional method, and the process of mechanical bonding, compression bonding, and sintering is combined. ) It is completely integrated as a ceramic component and can withstand continuous high-temperature rotation as a gas turbine rotor, etc., making it suitable as an automobile component.

[Brief explanation of the drawing]

Fig. 1(a) shows a cross-sectional view of the wing portion of Example 1, the same <(b) shows a Wr side view of the shaft portion, and Fig. 2 shows a cross-section of the molded body in which the upper Ha members are joined. FIG. 5(C) shows a side view of the shaft portion of Example 2, and FIG. 3(d) also shows a cross-sectional view. In the figure, 1... Feather portion 1a... Convex portion 2... J1411 group 2a... Concave portion 6... Joint portion 4... Molded body 5... Rubber group watch applicant Toyota Motor Corporation company

Claims (1)

[Claims] ■ A member that uses a ceramic resin composition containing ceramic powder, a thermoplastic resin, and an organic binder as main components, has the shape of a desired molded object that is completely divided, and is mechanically bonded and solidified. ■ A process of assembling and joining the above-mentioned members; ■ A process of liquid-tightly sealing at least the joint portion of the combined molded product; Alternatively, the process of pressurizing the bonded part by hydrostatic pressure in a liquid at a local temperature, ■ the process of heating and removing the organic components of the integrated molded body, and ■ the process of # in the above process. A method for manufacturing ceramic parts, characterized by the step of firing a degreased body.