JPS62256762A - Carbonaceous powder for oxidation-resistant high density high strength carbon material and manufacture - 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 Application Field> The present invention is applicable to crucibles, sealing materials, shielding materials for nuclear reactors, nozzles for rocket and jet engines, etc., which require high density and high strength as well as oxidation resistance. The present invention relates to the composition and manufacturing method of carbonaceous powder for carbon materials used in the field of carbon materials.

<Prior art and its problems> Carbon materials have extremely excellent properties such as heat resistance at high temperatures (non-oxidizing atmosphere), chemical resistance, good electrical conductivity, lightness, lubricity, and neutron moderation ability. Therefore, it is used in industrial applications. However, in addition to being difficult to increase density and strength, it also has the disadvantage of being easily oxidized and deteriorated in an oxidizing atmosphere, which limits its use.

In order to solve these essential problems of carbon materials,
In recent years, remarkable improvements and research have been made. for example,
From the perspective of increasing the density and strength of carbon materials,
In the past, carbon materials were traditionally produced by mixing aggregate coke and pitch as a binder, grinding, firing, and graphitizing, but in recent years, high density and high strength materials have been produced without the use of binders. Methods have been proposed to attempt to produce carbon materials.

For example, a method using optically anisotropic small spheres as seen in JP-A-49-2379, or JP-A-54-64.
An example is the method using ground raw coke in No. 096. The carbon material manufactured by Kan's conventional method had a bulk specific gravity l of 65 to 1.75 g/crn', +ff+ L and a strength of 400 to 600 kg/crn' at best, whereas the latter's new manufacturing method had a bulk Specific gravity 1.
9~2.0g/c, bending strength 800~1000kg
It is possible to increase the density and strength of /crn2, and it is attracting attention. In this way, remarkable progress has been made in increasing the density and strength of carbon materials, but even these high-density and high-strength carbon materials are slightly superior to general carbon materials in terms of oxidation resistance. However, it is easily oxidized in air at temperatures above 500°C, and improving its oxidation resistance has been an important issue.

In addition, as a method for producing isotropic, high-density, high-strength, carbon material raw material powder, after heat-treating the pitch, the generated optically anisotropic small spheres are extracted with a solvent and calcined (Japanese Unexamined Patent Application Publication No. 1983-1999). 15
No. 7791) has been proposed. Although the optically anisotropic small spheres themselves are anisotropic, their spherical shape makes them isotropic after molding, and they have self-sintering properties, so they can be molded without the use of a binder. Provides isotropic, high-density, and high-strength carbon materials.

A method for producing a high-density, high-strength carbon material with excellent oxidation resistance is a method of blending a mixture of B, C (boron carbide), and 5iC (silicon carbide) with the above-mentioned ground raw coke, followed by molding and firing (special method). Japanese Patent Application No. 60-248557) has been proposed, in which boron carbide is mixed into optically anisotropic small spheres and then molded and fired.

On the other hand, a method of coating the surface of a carbon material with a ceramic film, and a method of impregnating the inside of the carbon material with a phosphoric acid compound or a silica-based solution are actually practiced.

However, in the method using ground coke,
It takes an extremely long time to grind raw coke, develop self-sintering properties, and mix it uniformly with ceramics, and the core carbonaceous material is limited to only ground raw coke with extremely poor crystallinity. And the raw coke itself is 600~
It has had problems such as rapid shrinkage in the temperature range of 1000°C, making it difficult to stably manufacture large blocks.

On the other hand, the method of coating the surface of a carbon material with ceramics has problems such as easy peeling due to uneven coating or a difference in coefficient of thermal expansion between the carbon material and the ceramics. Furthermore, the impregnation method has the disadvantage that the pore size and porosity of high-density, high-strength carbon materials are small, making it difficult to uniformly impregnate the inside, and that the improvement in oxidation resistance is limited to the vicinity of the surface. have

<Objective of the Invention> The object of the present invention is to produce a carbon material containing ceramics that can industrially stably produce a carbon material with high density, high strength, and excellent oxidation resistance, regardless of the type of ceramics or the type of carbonaceous material. The present invention provides a carbonaceous powder and an economical method for producing the carbonaceous powder.

<Structure of the Invention> According to the research of the present invention, etc., the composition of carbonaceous powder that can produce carbon materials with excellent oxidation resistance including ceramics is 100%.
The quinoline-soluble portion of the carbonaceous material contains 1 to 50 wt% of ceramics based on the weight of the carbonaceous material (hereinafter referred to as QS component)
The amount of is 10 to 50 parts by weight per 100 parts by weight of quinoline insoluble matter (hereinafter referred to as Ql component) in the carbonaceous material, and the benzene insoluble matter (hereinafter referred to as Bl component) and benzene soluble component in the quinoline soluble matter. (hereinafter referred to as BS component) was found to be optimal in a ratio of 5 to 30 parts by weight of benzene soluble component (BS component) to 100 parts by weight of benzene insoluble component (Bl component).

The above-mentioned carbonaceous powder for high-density and high-strength carbon materials having excellent oxidation resistance can be produced by the following method.

(1) Contains 1 to 50 wt% of ceramics based on 100 parts by weight of carbonaceous material, and the amount of quinoline soluble content in carbonaceous material is 10 to 50% by weight per 100 parts by weight of quinoline insoluble content in carbonaceous material.
0 parts by weight, and the ratio of benzene-insoluble to benzene-soluble in the quinoline-soluble content is 5 to 30 parts by weight per 100 parts by weight of benzene-insoluble. Excellent oxidation resistance. In producing carbonaceous powder for high-density and high-strength carbon materials, ceramics are added to tar and pitch, and after thorough stirring, a solvent that has a weaker extraction power than quinoline for tar and pitch is added to the raw material tar and pitch. A method for producing a carbonaceous powder for a high-density and high-strength carbon material having excellent oxidation resistance, which comprises using 200 to 1000 parts by weight per 100 parts by weight and performing an extraction filtration operation to obtain a carbonaceous powder.

(2) Contains 1 to 50 wt% of ceramics based on 100 parts by weight of carbonaceous material, and the amount of quinoline soluble content in the carbonaceous material is 10 to 50% by weight per 100 parts by weight of quinoline insoluble content in the carbonaceous material.
0 parts by weight, and the ratio of benzene-insoluble to benzene-soluble in the quinoline-soluble content is 5 to 30 parts by weight per 100 parts by weight of benzene-insoluble. In producing carbonaceous powder for high-density and high-strength carbon materials, ceramics are added to tar and pitch, thoroughly stirred, and then heat-treated at a temperature of 500°C or less. High density with excellent oxidation resistance characterized by obtaining carbonaceous powder by performing extraction and over-operation using 200 to 1000 parts by weight of a solvent with weak extraction power per 100 parts by weight of raw material tar/pitch.・Production method of carbonaceous powder for high-strength carbon material.

The present invention will be explained in more detail below.

In the present invention, tar pitch is used as the carbonaceous material. Not only tar/pitch and pitch alone, but also Q! It broadly refers to tar pitch to which acid components (coal-based or petroleum-based coke, optically anisotropic spherules, etc.) have been added.

As a result of detailed research into various sintering mechanisms of carbonaceous powder or carbonaceous powder containing ceramics, the present inventors found that sintering of carbonaceous powder is caused by the quinoline insoluble content (Ql component) in the carbonaceous powder.
Quinoline soluble component (QS component) uniformly dispersed around
It was discovered that this progresses by developing strong adhesive properties between the quinoline insoluble components (Ql component) after passing through a slight softening and melting process during firing of the molded body. Here, the quinoline insoluble content (Ql component) in carbonaceous material means petroleum-based or coal-based coke, optically anisotropic small spheres, etc., and can be regarded as an aggregate component.

Moreover, in order for the quinoline soluble content (QS component) to soften and melt during the firing process, a small amount of BS component is necessary, and the ratio of the BI acid component in the QS component is usually called the β component)
For 100 parts by weight, 5 weight + 11 In a system where there is no BS component, the β component does not soften or melt at all and cannot form strong adhesion between the aggregate components.However, in a system where some BS component is present, the BS component acts as a solvent and the β component is easily bonded. During the firing process, the BS component softens and melts, creating strong adhesion between the aggregate components.The BS component has a low carbonization yield and is said to not have large cohesive strength. It plays a major role in the expression of force.

On the other hand, if the amount of the BS component increases too much, the fluidity of the QS component system increases, which tends to cause cracking and blistering phenomena in the molded body during carbon material production, and also causes a large amount of volatile matter to be generated during firing of the molded body. The amount of BS component present is 30 parts by weight per 100 parts by weight of the β component (i.e. Bl component in the QS component). It must be below the department.

Furthermore, in a system where the QS component is uniformly dispersed around the aggregate component, the amount of QS component (i.e. Q1 in the carbonaceous material) is
Ingredients) per 100 parts by weight! It is sufficient if the amount is less than 0ffi parts.On the other hand, if it exceeds 501i parts, the volatile content increases as a whole, and the fired product is more likely to crack and swell.

The amount of ceramic added to such carbonaceous material is 1 to 5
0wt%, preferably 1 to 20W[%. If the amount of ceramic added is less than 1%, sufficient oxidation resistance at high temperatures cannot be expected, while if it is added 50wt%, the ceramic particles will inhibit the adhesion of the carbonaceous aggregate particles, resulting in high strength. carbon materials cannot be manufactured.

The types of ceramics added are 5iC1B, C
, Si, BN, etc. or a mixture thereof are effective. In addition, the particle size of aggregate components such as ceramics, petroleum coke, coal coke, optically anisotropic small spheres, etc. affects the properties of the obtained carbon material, so fine particles are desirable, and usually 20μm (preferably 10μm
m) Desirably the following. The carbonaceous powder containing ceramics obtained in this way can be shaped and fired as it is without the need to add a binder, and graphitized if necessary to achieve a bending strength of 800 to 120.
A carbon material with excellent oxidation resistance can be obtained at 0 kg/crn'.

Further, a manufacturing method capable of industrially stably manufacturing the carbonaceous powder containing the ceramics will be described in detail below.

As mentioned above, it is important that the ceramic-containing carbonaceous powder has the QS component, which is a caking component, uniformly dispersed around the ceramics and the QI acid component (aggregate component) in the carbonaceous powder. Therefore, the conventional method of mixing a predetermined amount of powdered aggregate components and highly viscous viscous components requires a large amount of power and a long time, and even with that, it is difficult to obtain a satisfactory dispersion. be.

The present inventors added a predetermined amount of ceramics, coke (petroleum-based and coal-based coke), optically anisotropic small spheres, and other aggregate components to low-viscosity tar and pitch, and after thorough stirring and mixing. It has been discovered that carbonaceous powder containing desired ceramics can be produced by solvent extraction using a solid solvent.

Possible solvents include benzene, toluene, pyridine, tar light oil, tar medium oil, etc., which are weaker in extracting pitch than quinoline. The amount and composition of the remaining QS component (ratio of BI acid component to BS component) can be controlled by selecting the type of solvent used, the amount used, the number of extractions, temperature, time, etc. Generally, as the amount of solvent used increases, the amount of the remaining QS component tends to increase, while the BS component in the QS component tends to decrease. Furthermore, as the number of extractions increases, the amount of QS components and the BS component in the QS components tend to decrease.

Usually the amount of solvent used is 200 parts by weight to 1000 parts by weight per 100 parts by weight of raw material tar/pitch, and the number of extractions is 1 to 3 times.
times is appropriate. If extraction is performed using a solvent within this range, a carbonaceous powder with the desired composition can be obtained.

4 times before performing the extraction operation Cerami-14 Fukyo et al. Heat treating tar and pitch containing aggregate components such as coke and optically anisotropic spherules at temperatures below 500°C It is effective in increasing the affinity of the QS component, which is a viscous component, with aggregate components such as coke and ceramics, and controlling the amount and composition of the QS component. Heat treatment exceeding 500°C must be avoided because coking progresses rapidly and the QS component disappears. On the other hand, 400-500℃
At heat treatment temperatures of It can be considered an acid component.

Furthermore, in order to industrially produce carbon materials that are more stable and have oxidation resistance, it is necessary to add and stir ceramics or even aggregate components to tar/pitch, solvent extraction, or add and stir ceramics or aggregate components. The carbonaceous powder containing the ceramics of the present invention obtained through heat treatment and solvent extraction is heated to 200 to 50% in an atmosphere substantially free of oxygen.
It has been discovered that force treatment at 0°C is effective. That is, by subjecting the carbonaceous powder to a force position treatment at 200 to 500° C., the low volatile content in the QS component can be removed without losing the cohesive strength of the QS component. If the temperature is below 200°C, no effect of removing volatile matter can be expected, and if the temperature exceeds 500°C, the cohesive force of the QS component will rapidly disappear, so the force treatment temperature must be selected in the range of 200 to 500°C. Must be.

In this force position treatment, the amount of QS component in the carbonaceous powder is 1
00 parts by weight, or the amount of BS component in the QS component is 20 parts by weight relative to 100 parts by weight of the Bl component.
It is more effective when the amount is 30 parts by weight. In other words, carbonaceous powders containing ceramics having the above composition tend to crack or bulge in the fired bodies when the firing speed of large carbon materials or molded bodies is increased, and this is a problem from an industrial perspective. Although this poses a problem, carbon materials can be easily obtained by force position treatment.

During the force treatment, a reaction occurs in which a part of the QS component becomes QI, but the Ql component from the QS component still has strong cohesive strength, making it possible to produce a high-density and high-strength carbon material. is possible.

The present invention will be explained below with reference to specific examples.

<Example> (Example 1) Using a 202 autoclave, 2 wt% and 20 wt% of 84C and petroleum coke, which were crushed to about 10 μm, were added to tar pitch with a softening point of 60°C, and 15
The mixture was stirred and mixed at a temperature of 0°C. The tar pitch is 3
After extraction using twice the amount of oil in tar (boiling range, 140-270°C) at a temperature of 120°C for 2 hours, a filtration operation was carried out. After washing the excess residue lightly with acetone, it was washed under vacuum for 24 hours.
Drying was carried out at a temperature of 60°C for a period of time. The composition of the obtained carbonaceous powder containing 84C was as shown in Table 1.

Table 1. Composition of carbonaceous powder containing 84G The carbonaceous powder was processed into 80φ under a molding pressure of 800 kg/c
Molded in x30hmm size, baked at 1000℃, 2
000°C graphitization was performed. Physical properties of the obtained graphite material and air flow rate (4f/DIin) 1000°C x 2
An oxidation test was conducted at hr. For comparison, the special public service 1973
M in the optically anisotropic small sphere trade name shown in No. 57791
FC (manufactured by Kawasaki Steel Corporation) was molded into a size of 80φ x 30hmm under a molding pressure of 800 kg/crn', and further 10
Table 2 also shows the test results of a ceramic-free high-density, high-strength graphite block obtained by firing at 00°C and graphitizing at 2000°C.

(Example 2) SiC and B ground to about 10 μm using a 20IL autoclave on tar pitch with a softening point of 60°C,
After adding 1.5 wt% of each of C and stirring and mixing the tar pitch at a temperature of 150°C, the mixture was further heated at 430°C
Heat treatment was performed for 0.5 hour under normal pressure. During this heat treatment, the formation of optically anisotropic spherules was observed.

The heat-treated pitch was mixed with four times the amount of tar oil (boiling point range, 14
After extraction at a temperature of 120°C for 2 hours, a filtration operation was performed. The extraction process was repeated twice. After washing the residue lightly with acetone, it was placed under vacuum for 24 hours.
Drying was carried out at a temperature of 60° C. for hours. The composition of the obtained carbonaceous powder containing SiC and 84G was as shown in Table 3.

Table 3. Composition of carbonaceous powder containing SiC and 84G Si (
:+84(: ・6.3wt%Ql :
72.9 wt% The carbonaceous carbonaceous powder was molded into a size of 80 φ x 30 hmn under a molding pressure of 800 kg/cm'', and further 1
000°C firing and 2000°C graphitization were performed. Table 4 shows the physical properties and oxidation properties (experimental conditions were the same as in Example 1) of the graphite material obtained.

(Example 3) 20I1. A heat-treated pitch was obtained using an autoclave and following the same procedure as in Example 2.

The heat-treated pitch was mixed with three times the amount of tar oil (boiling point range, 14
After extraction for 2 hours at a temperature of 120° C., an excess residue was obtained. The residue was washed with acetone and then dried under vacuum at a temperature of 60° C. for 24 hours. The composition of the obtained carbonaceous powder containing SiC and 84G was as shown in Table 5.

Table 5.5 Composition of carbonaceous powder containing iC, B, and C SiC
+l14G ・5.7wt%Ql:
66, Owt% 33 in the carbonaceous powder air stream
After performing force treatment at 0°C for 3 hours,
80φX30hnon under molding pressure of kg/cny'
Shaped to size, then fired at 1000℃, then 2000℃
Graphitization was performed. Table 6 shows the physical properties and oxidation properties (experimental conditions were the same as in Example 1) of the graphite material obtained.

Table 2. Physical properties and oxidation reactivity of graphite block Invention example 1.99 3405' +250
'109 1.1 Comparative example 1.92
1210 1080 87 100
Table 4. Physical properties and oxidation reaction table of graphite blocks
6. Physical properties and oxidation reactivity of graphite block Invention example 1.98 3800 1190
105 1.2 <Effects of the Invention> Since the carbonaceous powder for carbon materials containing ceramics of the present invention contains ceramics, it has high density and high strength as well as extremely excellent oxidation resistance.

Furthermore, according to the method of the present invention, it is possible to produce raw material powder for an isotropic, high-density, and high-strength carbon material that has significantly superior oxidation reactivity compared to general carbon materials through a simple process.

The carbon material raw material powder produced according to the present invention can be used for carbon materials that require isotropy, high density, and high strength as well as oxidation resistance, such as crucibles, sealing materials, shielding materials for nuclear reactors, and nozzles for rocket and jet engines. It is expected to be used as a raw material.

Claims (3)

[Claims] (1) Contains 1 to 50 wt% of ceramics based on 100 parts by weight of carbonaceous material, and the amount of quinoline soluble content in the carbonaceous material is 10 to 5% by weight per 100 parts by weight of quinoline insoluble content in the carbonaceous material.
0 parts by weight, and the ratio of benzene-insoluble to benzene-soluble in the quinoline-soluble content is 5 to 30 parts by weight per 100 parts by weight of benzene-insoluble. Carbonaceous powder for high-density and high-strength carbon materials with excellent properties. (2) Contains 1 to 50 wt% of ceramics based on 100 parts by weight of carbonaceous material, and the amount of quinoline soluble content in the carbonaceous material is 10 to 50% by weight per 100 parts by weight of quinoline insoluble content in the carbonaceous material.
0 parts by weight, and the ratio of benzene-insoluble to benzene-soluble in the quinoline-soluble content is 5 to 30 parts by weight per 100 parts by weight of benzene-insoluble. In producing carbonaceous powder for high-density and high-strength carbon materials, ceramics are added to tar and pitch, and after thorough stirring, a solvent with a weaker extraction power than quinoline for tar and pitch is added to the raw material tar and pitch. A method for producing a carbonaceous powder for use in high-density and high-strength carbon materials having excellent oxidation resistance, characterized in that carbonaceous powder is obtained by performing an extraction filtration operation using 200 to 1000 parts by weight based on the weight part. (3) Contains 1 to 50 wt% of ceramics based on 100 parts by weight of carbonaceous material, and the amount of quinoline soluble content in the carbonaceous material is 10 to 5% by weight per 100 parts by weight of quinoline insoluble content in the carbonaceous material.
0 parts by weight, and the ratio of benzene-insoluble to benzene-soluble in the quinoline-soluble content is 5 to 30 parts by weight per 100 parts by weight of benzene-insoluble. In producing carbonaceous powder for high-density and high-strength carbon materials, ceramics are added to tar and pitch, thoroughly stirred, and then heat-treated at a temperature of 500°C or less. High-density carbonaceous powder with excellent oxidation resistance is obtained by performing extraction and filtration operations using 200 to 1000 parts by weight of a solvent with weak extraction power per 100 parts by weight of raw material tar and pitch. A method for producing carbonaceous powder for high-strength carbon materials.