JPH01167210A - Processed article of carbonaceous felt and production thereof - Google Patents

Abstract

PURPOSE:To provide the title processed article having excellent heat-insulation effect, high mechanical strength and free from fluffs, by forming a thermally decomposed carbon film on a surface of a gas-permeable carbonaceous felt and/or impregnating the carbon film in the felt. CONSTITUTION:Air in a vessel is substituted with N2 gas by supplying N2 gas through a gas-feeding pipe 8. The pressure in the vessel is reduced or the vessel is evacuated through a gas-exhaustion pipe 1 to keep the atmosphere in the vessel in a non-oxidizing state. An electric potential is slowly imposed to an induction coil 5 to heat a susceptor 6 and a carbonaceous felt 4 is heated by the radiant heat of the susceptor while controlling the temperature of the felt to a prescribed level. When the felt is graphitized to an extent, a halogen gas is supplied through the feeding pipe 8. The temperature is slowly raised or lowered after the completion of the surification process and the system is controlled to a prescribed temperature. A thermally decomposed carbon film is formed on the surface of a substrate by thermally decomposing a hydrocarbon gas such as C3H8 or a hydrocarbon compound or the thermally decomposed carbon is impregnated in the felt.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to metal heat treatment such as hardening, annealing, and brazing of metals, sintering of powder metals, vapor deposition of metals, refining and sintering of ceramic raw materials, etc. For carbonaceous felt processed products mainly used as heat insulators when performing high-temperature processing under reduced pressure or in an inert gas atmosphere, single crystal pulling equipment for semiconductor manufacturing, chemical or physical vapor deposition equipment, plasma processing equipment, etc. The present invention relates to a carbonaceous felt product mainly used as a heat insulating material, and a method for manufacturing the same.

[Conventional technology and its problems]

Traditionally, refractory bricks have been used as insulation materials for furnaces used at high temperatures, such as vacuum furnaces, but recently ceramic, rhinoceros, and rock wool foams, fiber bundle felt, and the like have been used.

Such inorganic fiber materials are lightweight, flexible, shape,
Since they are provided with almost uniform quality, they are easy to install in the furnace and provide reliable insulation, and they also have the same characteristics as being bulky, having a small heat capacity, and shortening heating and cooling times. However, on the other hand, these can be used for metal processing such as quenching, annealing, and brazing of metals, sintering of powder metals, vapor deposition of metals, refining and sintering of ceramic raw materials, etc. under reduced pressure or an inert gas atmosphere. Insulating materials used when performing high-temperature processing,
Several drawbacks have been pointed out when applied to application fields such as single crystal pulling equipment for semiconductor manufacturing, chemical or physical vapor deposition equipment, and plasma processing equipment.

The first drawback is heat resistance. That is, the heat resistance when using these inorganic fiber felts is usually 10
Q O'C level, even the best one is 1500
°C was the limit.

In order to compensate for these drawbacks of inorganic fiber-based materials, heat insulating materials have been proposed in which carbon-based felt or expanded graphite powder is compressed, molded, and covered with a suitable outer covering. When such a carbon-based material is used, it has extremely high heat resistance of about 3000°C and can be molded into a bulky shape, so it can also provide high heat insulation properties.

For example, the one using expanded graphite disclosed in Japanese Utility Model Application Publication No. 51-15767, the combination heat insulating material made of carbonaceous felt and carbon fiber disclosed in Japanese Utility Model Application Publication No. 50-39571, and the one disclosed in Japanese Patent Publication No. 50-35930. Carbon felt is fixed with phenolic resin as shown in the publication, or carbonaceous felt and airtight graphite sheet are bonded using a carbonaceous bonding body as shown in Publication of Utility Model Publication No. 58-29129. A laminated structure has been proposed.

These materials that use carbonaceous felt as the main insulation material have excellent heat resistance and insulation properties, but they must be used under highly and strictly controlled harsh reaction and operating conditions as in the above-mentioned applications. Several shortcomings are still being pointed out, as shown below.

The first drawback is that these insulation materials have a high impurity level, and when used in a reaction atmosphere at high temperatures, the impurities generated from the insulation materials can contaminate the product, resulting in quality deterioration and yield reduction. This is a contributing factor.

=5- The second drawback is that when such a porous insulation material is used under reduced pressure or high vacuum, the escape and inflow of gas inside the insulation material cannot follow the pumping speed every time the internal pressure of the device is raised or lowered. The insulation material expands and contracts, and this process is repeated until the insulation material is damaged and broken pieces of fibers, etc. that make up the carbonaceous felt inside, such as fuzz, flow out into the equipment.
Secondary drawbacks arise, such as contamination of the product with carbon fines. In addition, carbonaceous porous insulation materials have recently been developed in which the surface of the insulation material is coated with a resin such as phenolic resin and then carbonized, but even in this case, the surface coating is still missing due to deterioration due to long-term use. , and are not fully effective.

The third drawback is that many supports are required to install the carbonaceous felt into the equipment, and it is also necessary to drill bolt holes for the actual material in the equipment to be loaded. As a result, broken and scattered pieces of the carbonaceous felt, such as fuzz, etc., are deposited in various places within the apparatus, causing the object to be treated to be contaminated with carbon.

In addition, several difficulties have been pointed out in conventional methods for producing carbonaceous heat insulating materials. The conventional manufacturing method was usually performed as follows.

That is, first, a carbonaceous product (sometimes containing a portion of resin) or a semi-finished product thereof is placed in a firing furnace at a temperature of 800~
The process of heating to 1000°C to disperse and evaporate easily volatile components contained in the binder, etc., followed by firing and carbonization (Process A)
).

Next, the fired body is taken out and heated to approximately 3000° in a graphitization furnace, such as an Acheson furnace, a Kasdonner furnace, or an induction heating furnace.
A step of graphitizing by heating to C (step B).

Furthermore, the graphitized material obtained in this way is heated in a gas atmosphere containing halogen in a separate reactor to convert the impurity components contained therein into substances with high vapor pressure and volatilize them from the base material. and high purification (step C).

The drawback of such conventional methods, namely carbonization, graphitization, and high purity methods, is that the product must be moved from furnace to furnace for each step from calcination to graphitization and further to high purity. This requires transportation and damage to the materials.Secondly, each furnace must be heated and cooled each time, which requires energy and equipment costs such as waiting for the temperature to rise and fall. This poses a major problem in terms of operating efficiency.

In addition, recently, as a slightly more advanced method, firing (Step A) is performed in a separate furnace, and then graphitization (Step B) and purification (Step C) are performed in series at normal pressure using an Acheson furnace. A method was developed. However, this method has the following drawbacks. First of all, the site area is large, secondly, the power efficiency is low, and thirdly, due to the structural limitations of the furnace, contact between the halogen gas and carbon material is poor, and high purity is required under normal pressure. Due to the relationship, desorption of halogenated impurities is poor,
The operation time was long and the amount of halogen consumed was large.

[Problem that the invention seeks to solve]

The problem to be solved by the present invention is to eliminate the above-mentioned drawbacks of conventional carbonaceous felt processed products or heat insulating materials made from the same, and methods for manufacturing the same. An object of the present invention is to provide a high-quality, low-cost carbonaceous felt processed product that is large in size, has excellent moldability and handleability, and does not generate fuzz, and a method for producing the same.

[Means to solve the problem]

This problem is solved by (i) forming a pyrolytic carbon film on the surface of the carbonaceous felt or (and) impregnating the inside of the felt with the pyrolytic carbon; and (ii) forming a carbonaceous felt into one layer. This problem can be solved by adopting a manufacturing method in which the equipment performs graphitization, high purity if necessary, and pyrolysis carbon generation treatment.

That is, in order to solve the above-mentioned drawbacks of conventional processed products using carbonaceous felt or insulation materials made of carbonaceous felt, the present inventors have attempted to produce processed products of higher purity, which could not be achieved by conventional methods, more economically. In order to develop a manufacturing method, as a result of extensive research, we have found that carbon hydrogens, especially 01
~ C8, most easily available is C3H11, etc., by thermally decomposing a hydrocarbon gas or hydrocarbon compound to form a pyrolyzed carbon film on the surface of the carbonaceous felt, or (and) when penetrating into the inside, use fluff. It was discovered that it is possible to obtain a robust carbonaceous felt processed product or a heat insulating material made from it, which is highly pure, has excellent heat insulating effect, and has good formability, without generation, and at the same time, it can be graphitized in one device and highly purified if necessary. ,
By performing the pyrolytic carbon coating treatment sequentially or partially in parallel, the cost of moving goods, damage to hand-made carbon materials, cooling of equipment, reduction of energy loss associated with heating cycles, and equipment availability are reduced. While improving carbon quality, reducing halogen consumption due to high purity, and indirectly reducing exhaust and wastewater treatment costs, we are producing ultra-high purity carbon products that could not be achieved with conventional methods in terms of quality. The present invention has been completed based on the discovery that it is possible to develop an innovative manufacturing method to obtain the desired results.

[Structure and operation of the invention]

First, the structure of the carbonaceous felt processed product or the heat insulating material (hereinafter simply referred to as the heat insulating material) made of the carbonaceous felt product according to the present invention will be explained.

The heat insulating material according to the present invention forms a stable pyrolytic carbon film on the surface of a breathable carbonaceous felt, or (
and) penetrated into the interior.

In this way, in the heat insulating material of the present invention, by forming a pyrolytic carbon film on the surface or (and) infiltrating it into the inside, strong adhesion between the carbonaceous felt and pyrolytic carbon and the pyrolytic carbon Due to its excellent thermal shock resistance, it is possible to prevent broken pieces of the internal carbonaceous felt from escaping, contaminating the furnace atmosphere due to escaping, generating fuzz, and preventing contamination with the workpiece due to this scattering. It is possible to effectively prevent carbon from entering the object to be treated as an impurity.

Any conventionally used carbonaceous felt can be used, and more specifically, for example, those made from organic fibers, those made from coal, petroleum tar, pitch, etc., and those made from polycarbonate. Representative examples include those made from synthetic fibers such as vinyl alcohol and polyacrylonitrile, and those made from natural fibers such as lignin and recycled cellulose-based substances. Furthermore, carbon fiber mats obtained by forming filaments obtained from these raw materials into a felt shape, infusible and firing them can also be effectively used.

Further, in the present invention, graphitized carbonaceous felt can also be used.

Form dense and highly pure pyrolytic carbon on the surface of this carbonaceous felt, preferably with a film thickness of 5 to 500 μm, or (and) reduce the bulk density of the impregnated portion to 0.08 to 0.5 g.
/cJ. The pyrolyzed carbon used in this case must be particularly highly pure and gas-impermeable. Here, high purity means that the total ash content is lo
ppm or less, and gas impermeability means that the gas permeability is I x 10-5 (crfl/sec) or less, preferably 10-' in N2 gas latm using a gas permeation measuring device. (cJ/5ec) or less. At this time, if the purity is outside the above range, there is a tendency for the inside of the furnace to be contaminated by the impurities of the pyrolytic carbon coating itself, and if the gas permeability is higher than the above value, it will be contaminated by impurities from the carbonaceous felt. may occur. The film thickness is preferably 5-5
00 μm, particularly preferably about 20 to 100 μm,
If the thickness is less than 5 μm, the effect of preventing the generation of fuzz is insufficient, and the moldability is also insufficient, making it difficult to handle. Conversely, if the thickness exceeds 500 μm, peeling or embrittlement may occur during repeated heating and quenching. Moreover, the carbonaceous felt may be exposed and the effect of film formation may be insufficient. In addition, when pyrolytic carbon is infiltrated into the interior, the bulk density of the infiltrated part is 0.08 to 0.5 g/d, preferably 0.
．． It is about 15 to 0.3 g/c+fl. 0.08g/
When CTIY is not reached, the moldability and fuzz prevention of the carbonaceous felt are insufficient, and when it exceeds 0.5 g/c+#, the thermal conductivity increases and the heat insulation properties may deteriorate.

In the present invention, the method itself for forming or impregnating a pyrolytic carbon film is a separate field, as described in the literature such as "Introduction to Carbon Materials" (Carbon Materials Society, published in November 1972). This is a well-known fact, and to describe the embodiment of boat fishing, carbon-generating materials, e.g.
8 In particular, it is a product in which linear or cyclic hydrocarbon gases or hydrocarbon compounds having 3 to 4 carbon atoms are thermally decomposed, and pyrolyzed carbon is permeated and deposited on the base material to form a film on the surface. . On the other hand, for concentration adjustment, hydrocarbon 1
1.5 to 20 parts (by volume) of hydrogen gas (
Volume) Particularly preferably, 4 to 10 parts are mixed, and the total pressure is 3.
It is desirable to operate under conditions of 00 Torr or less, preferably 50 Torr or less.

When such operations are performed, hydrocarbons form giant carbon compounds near the substrate surface through dehydrogenation, thermal decomposition, polymerization, etc., which are deposited and precipitated on the substrate, and further dehydrogenation reactions occur. As the process progresses, a strong, impermeable pyrolytic carbon coating layer is formed or penetrated and impregnated. however,
Since the coexistence of 0□ and N20 has an adverse effect, it is preferable to avoid it.

The temperature range for precipitation is wide ranging from 800°C or less to about 2500°C.

In the present invention, the conditions for forming and/or penetrating the pyrolytic carbon film are not important at all, but only if a pyrolytic carbon film meeting the above predetermined requirements is formed or (and) penetrates into the interior. The forming conditions are not limited as long as they are carried out, and various forming methods can be effectively applied, and one embodiment thereof is as follows.

When forming a film on the surface of carbonaceous felt in pyrolytic carbon treatment, the coating temperature is approximately 1700°C to 2500°C.
'When infiltrating into the inside of C1, the temperature is approximately 1000°C ~ 130°C.
Preferably, the temperature is 0°C.

The reason for this is as shown below.

In the present invention, the pyrolytic carbon coating may be formed isotropically, but the graphite crystal basal plane, that is, the hexagonal carbon plane, may be selectively oriented parallel to the substrate surface (i.e., anisotropically). It is preferable to let Carbonaceous felt originally has an excellent heat insulating effect, but the heat insulating property can be further improved by orienting the pyrolytic carbon film in parallel. This specific orientation can be easily achieved by adjusting the temperature during the formation of the pyrolytic carbon film. By generating carbon, a film having the above-mentioned predetermined orientation can be effectively formed. The inventor's research to clarify this point revealed the following. That is, an X-ray diffraction pattern is taken for the pyrolytic carbon film, and its (
002) When the intensity of the diffraction line is used as a measure of the degree of selective orientation, the results are as shown in Table 1.

The results in Table 1 show that at the formation temperature of 1400 to 1600°C, the X-ray diffraction intensity is weak and a pyrolytic carbon film with small anisotropy is formed, whereas at 1000 to 13oo'c and 170
It is found that the pyrolytic carbon film, which has a strong diffraction intensity and large anisotropy, is selectively oriented at 0 to 2500°C.

Therefore, in the present invention, the above temperature range is preferable in terms of improving the heat insulation effect.

=17- The carbonaceous felt used in the present invention is preferably highly purified. In this case, high purification means that the content of inorganic impurities is small, and it is usually preferable that the total amount of impurities is 10 ppm or less.

The high purification method in this case is to bring the felt into contact with a halogen-containing gas under reduced pressure and high temperature, and remove the metals contained as impurities by converting them into halides with higher vapor pressure (for example, in a patent application 6l-224131), but is not limited thereto. Examples of the halogen-containing gas used at this time include chlorine, fluorine, and gases of compounds thereof, and specific examples include ethane difluoride, fluorine gas, and the like.

It is preferable to purify the carbonaceous felt as high as possible to the inside, and for this reason, it is effective to carry out the purification in advance before performing the pyrolytic carbon treatment. That is, in order to achieve high purity inside the felt, the effect will be small unless the halogen compound penetrates into the inside and the halogenated and vaporized impurities are not removed from the felt 1 to the outside. For this purpose, it is preferable to perform the pyrolytic carbon treatment after the breathable carbonaceous felt is highly purified in advance.

Further, in order to more quickly and reliably achieve high purification, it may be preferable to vary the pressure within the reaction vessel to increase or decrease it. This is especially effective when the felt has high air permeability.

Generally, for high purification, the inside of the reaction system is kept under reduced pressure conditions, for example, 100
150°C of carbonaceous felt while maintaining the total pressure below Torr.
The temperature is maintained at 0 to 2000°C, and the halogen compound is allowed to flow through it. Increase or decrease the pressure within the reaction system as necessary.

Now, Table 2 shows the measured amount of impurities in the carbon felt that was highly purified by keeping it at 2000° C. for 5 minutes, and also shows the amount of impurities in the raw material felt that was not purified as a reference value.

However, Table 2 shows an example of a combination of pyrolytic carbon using propane as a raw material gas and felt using coal-based tar as a raw material.The details of the high purity conditions, felt used, etc. are as follows. be.

High purification conditions: Temperature: 1800°C Vacuum degree: 20T
Physical properties of felt using Orr gas = difluoroethane: Pitch-based felt bulk density
0.07g/c+f1 surface In Table 2, the above is used, but if other hydrocarbon gases, graphite from other production areas, petroleum-based raw materials, etc. are used, the types of impurities will be different. However, in any case, the amount of impurities can be reduced to 10 pp by the method of the present invention.
It can be easily lowered to below m.

Furthermore, high-temperature firing for high-purity treatment also brings about the secondary advantage that the internal carbonaceous felt layer is graphitized and strengthened.

Table 2 Next, a method for manufacturing a heat insulating material according to the present invention will be explained.

The method for manufacturing the heat insulating material of the present invention basically involves graphitizing carbonaceous felt to make it highly purified, and then forming a pyrolytic carbon film on the surface of the carbonaceous felt or (and) infiltrating the inside of the carbonaceous felt. This is a method in which each step is performed under reduced pressure or high vacuum using high-frequency heating means, and one preferred example thereof is a method using the apparatus shown in FIG.

Using this equipment, further graphitization and high purification steps are carried out sequentially.
Alternatively, at least some of the steps may be performed in parallel. A more detailed explanation of the method of using this device is as follows.

First, N2 gas is supplied from the gas supply pipe (8) to replace the air inside the container with N2 gas, and then the gas discharge pipe (1)
Reduce the pressure or create a vacuum to make the atmosphere non-oxidizing.

Next, a voltage is gradually applied to the induction coil (5) to heat the susceptor (6), and the carbonaceous felt (4) to be heated is heated to a temperature of 1500 to 3000"C and graphitized by the radiant heat. At a certain stage, a halogen gas, such as ethane difluoride, is supplied from the gas supply pipe (8) (the flow rate is increased or decreased depending on the amount of carbon material to be heated filled in the container, but for example, about 1 to 7 NTP/kg). Supply for about 3 to 8 hours.

The inside of the container is maintained at 100 Torr or less, preferably about 1 to 50 Torr, from the time heating is started.

When the high purification operation is completed, the temperature is gradually raised and lowered to about 1000 to 1300°C or 1700 to 2500°C, and the surface of the substrate is heated while thermally decomposing hydrocarbon gases such as C3HI1 or hydrocarbon compounds. A coating of pyrolytic carbon is formed on and/or infiltrated into the pyrolytic carbon.

Approximately 1500-2000°C during the process of cooling the device
By strongly reducing the pressure inside the container to 10-'' to 10-' Torr and cooling it, high-valent impurities can be removed and a high-purity heat insulating material with little outgassing can be obtained.

Turn off the electricity, fill the container with N2 gas, and return to normal pressure and temperature while replacing the gas.

Although the above method shows a method in which both graphitization and high purity are carried out in one furnace, it goes without saying that in the present invention, only high purity may be carried out by the above method.

In the impurity removal section and high purification operation, the vacuum high frequency heating furnace according to the present invention is extremely convenient. That is, when the carbonaceous felt to be heated is brought into contact with halogen under reduced pressure or high vacuum, the first advantage is that the amount of halogen consumed is extremely small. Under reduced pressure or high vacuum, the halogen gas expands and is used, resulting in high utilization efficiency and good contact with felt.According to the inventor's experimental research, 10 ff1NTP/kg in the case of an electrified bed furnace. Compared to this, when the apparatus shown in FIG. 1 is used, the consumption of halogen-containing gas can be reduced to 311 TP/kg and 173 TP/kg.

The second advantage is that halogen or (and) hydrogenated impurities in the felt are easily volatilized and released to the outside due to the reduced pressure, so it is faster despite using a small amount of halogen gas. , it is possible to obtain products of higher purity.

In the present invention, it is desirable to keep the pressure inside the container within a range of 100 Torr or less when high purification or graphitization is carried out. The pressure inside the vessel is due to the presence of halides, chlorinated and/or fluorinated impurities, or residual N during substitution.
It is shown on a pressure gauge as the sum (total pressure) of the vapor pressures (partial pressures) of various compounds such as two gases, but if this is higher than 100 Torr, the pressure reduction effect will be low, and therefore the time required for high purity will be longer. The effect of lowering purity is also not so large. The carbonaceous felt processed product of the present invention has extremely excellent heat insulating properties and is extremely suitable as a heat insulating material.

As an example of the application of the present invention, when the pressure inside the reaction vessel is varied to increase or decrease during high-purity operation, diffusion of halogen gas into the deep layer of the felt,
Replacement, removal of the halogenated product from the deep layer, and replacement may be complete, which is more effective.

Example EXAMPLES The present invention will be specifically described below with reference to Examples.

Example 1 A heat insulating material was produced in a high frequency induction electric heating furnace shown in FIG. In addition, as the carbonaceous felt, commercially available carbon mat obtained from coal-based pitch (bulk density 0°06g/c+fl
)It was used. By stacking 5 sheets of this and depositing pyrolytic carbon on the surface as shown below, 50X50X
A laminated flat plate with a thickness of 20 mm (t20 mm) was obtained.

First, the carbon mat was fixed with a jig and placed in an induction heating furnace, and graphitized, purified, and coated with pyrolytic carbon in this order. The conditions for graphitization and high purity are approximately 40 Torr.
The temperature was raised to about 2000''C under reduced pressure of 2000 ℃, and heating was continued for 5 to 8 hours.

From the state where graphitization and high purification have been completed as described above, the temperature is further lowered to about 100~1300''C, and C3
H8 flow rate 35 ffi/min, C3He/H2
0.2 (volume ratio 20%), pyrolytic carbon was formed on the surface of the carbonaceous felt or (and) infiltrated into the inside. The thickness of the coating was adjusted to the thickness shown in Table 3 by varying the deposition time. Next, the temperature was lowered from this state, the pressure was returned to normal pressure, and then the mixture was allowed to cool. Rapid heating and cooling tests were conducted on these. That is, the heating angle was increased to 1300° C. for 5 minutes, and the heated heat insulating material was thrown into water to be rapidly cooled, and the peeling state of the pyrolytic carbon coating was examined. The number of samples is 5 each. The results are shown in Table 3.

In addition, the bending strength, compressive strength, and
Table 3 shows the thermal conductivity in the direction perpendicular to the deposition surface.

Example 2 In the above-mentioned Example 1, ethane difluoride was introduced into the firing furnace during the above-mentioned high purification step. It is clear that the impurities became halides with high vapor pressure and were excluded from the reaction system. The analytical values of the product are shown in Table 2.

〔Effect of the invention〕

As explained below, according to the high-purity heat insulating material and the manufacturing method thereof using the vacuum high-frequency heating method according to the present invention, the following excellent effects are exhibited.

(Insulating materials made by thermally decomposing hydrocarbon gas or hydrocarbon compounds such as 11C3HB gas on the surface of carbonaceous felt or (and) inside it have the heat insulation effect of pyrolyzed carbon in addition to the heat insulation effect inherent to carbonaceous felt. , adhesion effects, etc. are also taken into account, and due to the synergistic effect of carbonaceous felt and pyrolytic carbon, it is highly pure and has excellent heat insulation effects, and is lightweight and has good moldability.
It is superior in terms of mechanical strength.

(2) Since the surface or (and) the inside of the carbonaceous felt is coated with pyrolytic carbon, the generation of fuzz can be prevented and the inside of the furnace will not be contaminated.

(3) Since the purification reaction is carried out in a vacuum container, the amount of halogen gas consumed is small, the time required for the purification process can be shortened, and a heat insulating material with higher purity can be obtained.

(4) Since the graphitization, high purification, and pyrolytic carbon coating processes can be performed simultaneously, sequentially or partially in parallel, in one furnace, there is no need to take out and put the product in the middle, and the temperature is raised continuously. Both thermal efficiency and equipment operating efficiency are significantly improved compared to conventional methods.

(5) Also, as a side effect of forming the pyrolytic carbon coating layer, there is an advantage that outgas is extremely reduced. This fact was newly discovered by one of the inventors, but due to the synergistic effect of this pyrolytic carbon coating effect and the heavy metal (ash) removal effect of high purification treatment, It is possible to suppress contamination of impurities from heat insulating materials used in various devices to extremely low levels.

These are generally effective when used under reduced pressure and high temperatures, but they are particularly effective under conditions of temperatures below 30 Torr and below 500°C. IT.

It is extremely effective as a heat insulating material for high performance equipment exposed to high vacuum and high temperature conditions at temperatures below 800°C.

[Brief explanation of the drawing]

FIG. 1 schematically shows a side cross section of an example of a vacuum type/high frequency heating type high-purity carbon material manufacturing apparatus according to the present invention. (1) Gas exhaust pipe (2) Heat insulation material (3) Heat insulation material (4) Heat insulation material (5) ...High frequency coil (6) ...Susceptor (7) ...Insulation tray (8) ...Gas supply pipe (9) ...・Water cooling jacket (below) Patent applicant: Toyo Tanso Co., Ltd.

Claims (1)

[Scope of Claims] (1) A processed carbonaceous felt product made by forming a pyrolytic carbon film on the surface of a breathable carbonaceous felt or (and) infiltrating the inside thereof. (2) The high-purity carbonaceous felt processed product according to item 1, wherein the inorganic impurity is 10 ppm or less. (3) The carbonaceous felt product according to claim 1 or 2, wherein the pyrolytic carbon coating has a thickness of about 5 to 500 μm. (4) The processed carbonaceous felt product according to any one of claims 1 to 3, wherein the bulk density of the portion into which pyrolytic carbon is infiltrated is 0.08 to 0.5 g/cc. (5) The method for producing a processed carbonaceous felt product according to any one of claims 1 to 4, characterized in that the carbonaceous felt is subjected to graphitization and pyrolytic carbon generation treatment in the same apparatus. (6) Prior to graphitization, or (and)
6. The manufacturing method according to claim 5, wherein a high purification treatment is performed in the same apparatus after graphitization and before the pyrolytic carbon generation treatment. (7) The manufacturing method according to claim 5 or 7, wherein each of the above treatments is performed using high-frequency heating means under reduced pressure or high vacuum. (8) A method for manufacturing a high-purity carbonaceous felt processed product according to claim 6, characterized in that graphitization and purification are carried out in parallel with some overlap. (9) In the method for manufacturing a high-purity felt product according to any one of claims 5 to 8, at least one of graphitization and high purity is performed under a pressure of 100 Torr or less. Characteristic manufacturing method. (10) The halogenation reaction and the separation reaction of the halogenated product are carried out simultaneously in the high purification step under reduced pressure or high vacuum conditions. The manufacturing method described in any of the above. (11) A heat insulating material comprising the processed product according to claim 1.