KR920005409B1 - Preparing method of carbon/ceramic composite - Google Patents

Abstract

A carbon-ceramics composite is produced by (1) adding pitch system (isotropic and/or anisotropic) 10-40 wt.% with more than 300 deg.C of melting temperature as a carbon source, into a blast furnace water granulating slag 60-90 wt.% as a ceramic source, (the size of the mixed powder of the above pitch and slag is less than 0.074 mm), (2) pressure molding under the range of 100-500 kg/cm2 G, (3) heating the above molding material at a rate of less than 10 deg.C/ min in inert gas atmosphere, and (4) sintering the above (3) for 1 hour in the temperature range of 1,050-1,150 deg.C.

Description

Manufacturing method of carbon / ceramic composite using pitch and blast furnace slag

1 is a graph showing the change in compressive strength according to the carbon content of the carbon / ceramic composites calcined at 1050 ℃ by the method of the present invention.

2 is a graph showing the change in compressive strength according to the carbon content of the carbon / ceramic composites fired at 1150 ℃ by the method of the present invention.

The present invention relates to a method for producing a carbon / ceramic composite material, and more particularly to a method for producing a carbon / ceramic composite material using pitches and blast furnace slag. Carbon / ceramic composite material combines the characteristics of carbon materials such as light weight, heat resistance, thermal shock resistance, conductivity and ceramic material characteristics such as oxidation resistance, mechanical strength, and so on. It is used for various purposes such as perturbation, corrosion resistance, and electrode. In general, as a feedstock for the production of carbon / ceramic composites, carbon, graphite and raw coke or plastic coke of Whisker-reinforced type are used for carbon, and in the case of ceramics, oxide (Al ₂ O) is used. ₃ , Y ₂ O ₃ , SiO ₂ ), carbides (SiC, B ₄ C), nitrides (Si ₃ N ₄ ), and the like are used.

Carbon / ceramic composites have a variety of structures and can be roughly classified into composite materials including fibers and composite materials without. In addition, in the manufacturing method, various manufacturing methods have been developed according to the structure of the composite material. However, when the fiber is not used, there are a powder mixed sintering method and a molding impregnation method. Powder mixing and sintering methods include: 1) mixing raw coke powder, SiC and B ₄ C powder, and pressing them for sintering under inert atmosphere (Japanese Patent Publication No. 59-131576, 59-213674), 2) There is a method of heating and pressing a metal oxide mixture (Japanese Patent Laid-Open Publication No. 56-37192, 58-6711, 61-27352), but the raw materials used are SiC, B ₄ C, Si ₃ N ₄ , and the like. By using high purity raw materials such as Al ₂ O ₃ , Y ₂ O _3, etc., the manufacturing cost of the composite material is increased.

It is an object of the present invention to produce carbon / ceramic composite materials without using conventional high-purity raw materials, but with pitches having a melting point of 300 ° C. or higher as carbon raw materials, and blast furnace chain slag as steel by-products as ceramic raw materials. It is to provide a method for manufacturing a composite material.

According to the present invention, 60-90 wt% of blast furnace slag slag as a ceramic raw material is added as a carbon raw material, and 40-10 wt% of pitches having a melting point of 300 ° C. or higher is formed under pressure under a pressure of 100-500 Kg / cm ² and then heated in an inert atmosphere. Provided is a method for producing a carbon / ceramic composite material which is heated at a rate of 10 ° C./min or less and maintained at 1050-1150 ° C. for 1 hour to be fired.

Pitches used in the present invention can be used together with isotropic or anisotropic liquid crystal pitch, and the melting point is preferably 300 ° C or higher. If the melting point is 300 ℃ or less, there is a fear that the deformation due to the melting of the pitch during firing, and the strength of the molded body due to the release of the volatile component is caused.

Pitch content is preferably about 10 to 40% by weight of the total weight of the pitch and crushed slag, when less than 10% by weight of the carbon content is too low, it is difficult to expect the effect as a carbon / ceramic composite material, more than 40% by weight If contained, warping and deformation of the molded body may occur.

On the other hand, the particle size of the mixed powder of the pitch and the crushed slag in the present invention is preferably 0.074mm or less, because when the particle size is larger than 0.074mm, not only the filling rate is lowered but also the strength of the moldability is not maintained.

Molding pressure is 100-500Kg / cm ² G are preferred bars, which 500Kg / cm ² G higher than the case has a defect, because the compression-molded article during manufacture (pressing flaw) caused 100Kg / cm ² G or less in the treated possible strength of the molded article The reason for limiting the temperature increase rate to 10 ° C./min or less is that since the decomposition of the pitch component is accelerated by rapid temperature increase, the deformation occurs after sintering due to excessive volatilization of the decomposition component. The reason for limiting the sintering temperature to 1050 ° C. to 1150 ° C. is that it does not maintain sufficient strength as a sintered body at 1050 ° C. or lower, and it is susceptible to deformation since magnetization occurs at 1150 ° C. or higher.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

Mixing pulverization using a mixer for 12 hours or more to change the mixing ratio of blast furnace slag powder and pitch powder to 90/10, 85/15, 80/20, 70/30, 60/40 by weight% to have a particle size of 0.074 mm or less After that, the molded body was manufactured by molding at a molding pressure of 100-500 Kg / cm ² G. The prepared molded article was heated at a heating rate of 10 ° C./min under an inert atmosphere and calcined at 1050 ° C. for 1 hour. The composition of the blast furnace slag used in this example is shown in Table 1, and the specific resistance of the composite material according to the content change is shown in Table 2 in the compressive strength in FIG.

TABLE 1

TABLE 2

According to Table 2 and FIG. 1, as the pitch content increases, the compressive strength increases, while the specific resistance decreases.

Example 2

After the molded product was produced by the same mixing molding method as in Example 1, the resultant was heated at a temperature increase rate of 5 ° C / min in an inert atmosphere and calcined at 1150 ° C for 1 hour. The compressive strength of the manufactured composite material is shown in FIG. 2 and the specific resistance is shown in Table 3. As can be seen from FIG. 2 and Table 3, as a result of firing at 1150 ° C., the compressive strength increased more than three times compared to Example 1 baked at 1050 ° C., and the electrical resistivity decreased to 1/10 or less.

TABLE 3

As described above, the present invention provides a carbon / ceramic composite material by using blast furnace slag as a by-product of iron and pitch as a residue of fossil raw material, thereby achieving high added value of steel by-products as well as manufacturing cost reduction of carbon / ceramic composite. You can do it.

Claims (1)

In the method for producing a carbon / ceramic composite material, 60-90% by weight of blast furnace slag is added under pressure of 100-500 Kg / cm ² G by adding 40-10% by weight of pitches having a melting point of 300 ° C. or higher, and A method of producing a carbon / ceramic composite material, wherein the temperature is raised to 10 ° C./min or less in an inert atmosphere and maintained at 1050-1150 ° C. for 1 hour for baking.

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