JPS62123067A - Manufacture of silicon carbide base honeycomb structure - 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 [Technical Field] The present invention relates to a method for manufacturing a silicon carbide honeycomb structure used in fields where heat resistance is required, such as heat exchangers and heating furnaces.

"Prior art and its problems" Conventionally, as a manufacturing method of this type of honeycomb structure, 4.
There is one shown in ¥ Open and Close No. 49-16711-. This manufacturing method involves laminating thin layers of organic material to form a honeycomb shape of desired shape and size, firing this in a neutral or reducing atmosphere furnace until carbonized, and then heating it in a similar atmosphere. 1600℃ to 2℃ in a silicon gas atmosphere
The carbonaceous structure is heated at a high temperature of 400° C. and reacted with silicon to form silicon carbide by a so-called reaction sintering method to obtain a honeycomb-shaped silicon carbide structure.

Furthermore, in JP-A No. 60-58847, a carbon-containing unbalanced sheet and a carbon-containing corrugated sheet are combined together and hardened, then coked, and then immersed in a molten silicon bath. A method of manufacturing a silicon carbide honeycomb structure is shown.

However, in 1-Production υ, if the honeycomb shaped body is placed in an IC dust atmosphere or immersed in a molten silicon bath and subjected to reaction sintering without specifying the direction of its ventilation passages, Depending on the old method, part of the molded product may be bent due to its own hair or distorted into a rhombus shape due to its own hair, or silicon content may remain in the part that should be hollow as a ventilation passage, causing the hollow part to become distorted. Problems such as narrowing and blockage and large loss of silicon have arisen.

The object of the invention is to reduce distortion during siliconization firing in a method for manufacturing a silicon carbide honeycomb structure in which a honeycomb formed body containing a carbon source is brought into contact with molten silicon or silicon vapor. It is an object of the present invention to provide a method for manufacturing a silicon carbide honeycomb structure, which can suppress the tendency of hollow portions to be blocked by residual silicon and obtain a honeycomb structure with high thermal conductivity and heat resistance.

``Summary of the Invention'' The present invention relates to the production of a honeycomb structure containing a carbon source 1 and a silicon carbide honeycomb structure by bringing the formed body into contact with molten silicon or silicon vapor. 4. The molten silicon or silicon gas is brought into contact with the molten silicon or silicon gas in such a manner that the molten silicon is oriented in the direction of the 1-degree force.

According to this method, by bringing a honeycomb formed body containing a carbon source into contact with molten silicon or silicon vapor,
The honeycomb formed body is converted into silicon carbide by reaction sintering. At this time, the distortion of the honeycomb molded body is minimized by setting the first air passage in the f force direction, which has the highest compressive strength, and the excess silicon flows through the air passage wall, which is set in the l nide direction, to the F force direction. Since it drips and flows, excess silicon does not accumulate in the joints and valleys of the thin plates that make up the honeycomb molded body.1 Therefore, silicon loss can be minimized, and the air passages tend to become narrower and clogged. Defense IL = possible. The honeycomb structure thus obtained has high thermal conductivity and high temperature I6# thermal properties, and has high utility value in fields such as heat exchangers and heating furnaces.

The M element X (contained in the lahoneycomb molded body of the present invention) is preferably carbon, but may be a 4i jj! J, carbon! compound, a non-aIR element compound, or a mixture of these and carbon. Although the obtained honeycomb structure mainly consists of silicon carbide, it may also contain metal silicon and/or carbon.

"Embodiments of the Invention" The present invention will now be described in more detail with reference to Examples.

(Example 1) As shown in FIG. 1, a PAN-based carbon fiber sheet impregnated with a thermosetting organic binder with a large residual carbon content such as phenol resin is formed into a corrugated plate 11 and a flat plate 12 having a sine curve cross section. It is molded and cured using a prescribed ζ go method. Such corrugated plates 11 and flat plates 12 are laminated and bonded in a predetermined manner to obtain a honeycomb molded body.

For example, a paste containing a mixture of silicon carbide powder and phenol resin can be used for bonding.

Further, a honeycomb obtained by providing required insertion holes in the corrugated plate 11 and the flat plate 12 in advance. Corrugated plate 11 on the molded body
Alternatively, a honeycomb formed body may be formed by inserting a book or two or more pipes so as to pass through the flat plate 12. In this case, the pipe and the laminate may be joined using the same paste as necessary. The pipe to be used is preferably an unfired or fired reaction-fired, I, I, or silicon carbide pipe.

In addition, the honeycomb molded body is made of 'IK' as shown in FIG.
It may also be obtained by extrusion molding a mixture of zE powder and silicon carbide powder, kneaded with methylcellulose and organic paint such as phenol resin.

In these honeycomb molded bodies, all of the formed air passages 13 run parallel to each other. When the obtained honeycomb molded body is calcined at a predetermined temperature in a non-oxidizing atmosphere, the organic binder is thermally decomposed and becomes porous, and a portion thereof is carbonized.

Next, as shown in the figure, such a honeycomb molded body is made so that the ventilation passages 13 face in the 1:F direction, and the
The part is brought into contact with molten metal silicon heated to 1500-IB00°C. In this case, the honeycomb 1 and the F part of the molded body may be directly immersed in the molten metal silicon bath, but preferably the honeycomb molded body is placed on supports 41 made of porous silicon carbide and a stand. Then, the lower part of this support +1 is immersed in a molten metal bath.

Metallic silicon is inserted into the porous support 1 or the honeycomb molded body.
When the carbon content is silicided by the phenomenon 11)1, it is impregnated into the rest of the porous honeycomb molded body at 11'. When silicon cools, it changes from a liquid phase to a solid phase.The volume expands by 1 in 1 time, so the excess metal silicon oozes out from the surface of the structure during solidification, but since the air passages are in the vertical direction, It flows downward along the inner wall of the ventilation passage 13 without being retained at the joint between the corrugated plate 11 and the W plate 12 or at the cross wall 14.

The molten silicon that stays at the bottom of the honeycomb structure can be reduced by creating a space in the base 1- or by making a hole in the base and providing a passage for it to flow. After removing the structure from the reaction sintering furnace,
The lower occlusion can also be removed by cutting. By contacting the molten metal silicon in this way, most of the carbon and mole components of the honeycomb formed body react and change into silicon carbide. Further, the joint portions to which the paste is applied are also filled with metal silicon, and the carbon content is changed to silicon carbide, which is firmly fixed. In this way, a honeycomb structure having the desired silicon carbide structure and whose pores are filled with one metal element is obtained with almost no distortion.

(Example 2) 'Carbonized L\NiL obtained in the same manner as Example 1
Similarly, the molded body is placed in a silicon vapor atmosphere at 1700 to 2400° C. with the air passage 13 facing toward the sea. As a result, most of the IN part of the honeycomb molded body is reacted and sintered with almost no distortion during firing, and after that, by immersing it in molten silicon, a desired silicon carbide honeycomb structure similar to that of Example 1 is obtained. can get.

"Effect of the invention" According to the method of the present invention, as described below.

The honeycomb molded body containing the jR element source is
The honeycomb structure is brought into contact with molten silicon or a silicon vapor atmosphere with the honeycomb structure facing in the direction, and the silicon is reacted and sintered with most of the charcoal of the honeycomb formed body, so there is almost no distortion in the resulting honeycomb structure. In addition, there is no excess retention of leached silicon during solidification in the joints when laminated or on the cross walls when extruded, minimizing silicon loss and preventing narrowing of the hollow part of the air passage. I can do it. In addition, most of the carbon content in the molded body is converted to silicon carbide, and the pores are also filled with silicon, making it possible to obtain a nicomb structure with high thermal conductivity and excellent heat resistance.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing one embodiment of the /S nicum molded product applied to the manufacturing method of the present invention, and Fig. 2 shows another embodiment of the /S nicum molded product applied to the manufacturing method of the present invention. FIG. 11... Corrugated plate, 12... Mo board, 13... Ventilation path
】4...Cross wall subtraction 1-cho sale available 11 Official book (method) % formula % 2. Name of the invention Method for manufacturing a silicon carbide honeycomb structure 3. Name to be amended 1. Relationship with the patent Applicant address: 2-111-2 Marunouchi, Chiyoma-ku, Tokyo Name (004) Asahi Glass Co., Ltd. 6 Number of inventions to be increased by amendment None 7 Drawings subject to amendment 8 Contents of amendment

Claims (1)

[Claims] In a method for producing a silicon carbide honeycomb structure in which a honeycomb formed body containing a carbon source is brought into contact with molten silicon or silicon vapor, the honeycomb formed body is placed in such a way that its ventilation passages are in the vertical direction, and the molten silicon or A method for producing a silicon carbide honeycomb structure, which comprises bringing it into contact with silicon vapor.