CA1245816A - Regulation of pyrolysis methane concentration in the manufacture of graphite fibers - Google Patents

Regulation of pyrolysis methane concentration in the manufacture of graphite fibers

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Publication number
CA1245816A
CA1245816A CA000485059A CA485059A CA1245816A CA 1245816 A CA1245816 A CA 1245816A CA 000485059 A CA000485059 A CA 000485059A CA 485059 A CA485059 A CA 485059A CA 1245816 A CA1245816 A CA 1245816A
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Prior art keywords
methane
fibers
gas stream
filaments
volume percent
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Application number
CA000485059A
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French (fr)
Inventor
Gary G. Tibbetts
Michael G. Devour
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Motors Liquidation Co
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Motors Liquidation Co
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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B82NANOTECHNOLOGY
    • B82YSPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00Nanotechnology for materials or surface science, e.g. nanocomposites
    • DTEXTILES; PAPER
    • D01NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01FCHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F9/00Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
    • D01F9/08Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
    • D01F9/12Carbon filaments; Apparatus specially adapted for the manufacture thereof
    • D01F9/127Carbon filaments; Apparatus specially adapted for the manufacture thereof by thermal decomposition of hydrocarbon gases or vapours or other carbon-containing compounds in the form of gas or vapour, e.g. carbon monoxide, alcohols
    • D01F9/1271Alkanes or cycloalkanes
    • D01F9/1272Methane

Abstract

REGULATION OF PYROLYSIS METHANE CONCENTRATION
IN THE MANUFACTURE OF GRAPHITE FIBERS

Abstract of the Disclosure In a preferred embodiment, graphite fibers are grown on a suitably nucleated ceramic surface by passing a methane gas stream over the surface at an elevated temperature. Initially, the methane concentration in the gas stream is adjusted to between 5 and 15 volume percent to form microscopic carbon filaments. Thereafter, the methane concentration is increased to above 25 volume percent to thicken the filaments into fibers.

Description

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REGULATION OF PYROLYSIS METHANE CONCENTRATION
IN THE MANUFACTURE OF GRAPHITE FIBERS
Background of the Invention This invention relates to a methane pyrolysis process for manufacturing graphite fibers of a type suitable for filler in plastic composites. More particularly, this invention relates to regulation of reactant methane concentration during sequential stages of fiber growth.
United States Patent No. 4,391,787, issued July 5, 1983 and assigned to the present assignee, describes a method for manufacturing thin, straight graphite fibers by natural gas pyrolysis carried out within a thin-wall stainless steel tube surrounded by wet hydrogen gas. The fibers are preferably 5 to 15 microns in diameter and up to several centimeters long and are well suited for plastic filler. In this process, fiber yrowth is attributed to a complex interaction between the chromium-bearing steel and methane at elevated temperature. United States Patent No. 4,491,569, issued January 1, 1985 and assigned to the present assignee, describes a method for growing the fibers on a ceramic surface, but only after natural ~5 gas pyrolysis is initiated adjacent stainless steel.
Stainless steel is relatively expensive and has a limited useful life at fiber growing temperatures.
Furthermore, unavoidable carburization of the stainless steel unproductively removes carbon and reduces yield.
Fiber growth is believed to proceed in two sequential stages. During a first stage, pyrolytic carbon interacts with metallic nuclei to form long, 5~

thin filaments less than 100 nanometers in diameter.
Suitable nuclei are derived from a deposit produced by evaporation of ferric nitrate solution, as described in U.S. Patent No. 4,491,569. Once nucleated, the filament grows rapidly in length. However, for reasons not fully understood, the filament then ceases to lengthen. Thereafter, additional pyrolytic carbon thickens the filament into a fiber that is several microns in diameter. It is believed that pyrolysis reactions initiated between the stainless steel and the natural gas in some manner control the nature and the concentration of carbonaceous precursors in the gas stream to favor first filament formation and then thickening.
Therefore, it is an object of this invention to provide an improved process for growing graphite fibers by natural gas pyrolysis on a ceramic surface that does not require that pyrolysis be initiated adjacent stainless steel.
More generally, it is an object of this invention to provide an improved process for growing graphite fibers by pyrolysis of a methane gas, wherein the methane concentration in the gas is regulated first at a value particularly conducive to reactions that nucleate and lengthen filaments and thereafter at a ralatively richer value for thickening the filaments into fibers. Although other parameters such as temperature, gas flow rate and nuclei characteristics also affect fiber growth, regulation of the methane concentration during each step improves the overall process by increasing yield, maximizing length and reducing growing time.

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~ 6 Summary of the Invention In accordance with a preferred embodiment of this invention, graphite fiber growth on a suitably nucleated ceramic surface by natural gas pyrolysis is improved by regulating the methane concentration in the reactant gas during each stage of the fiber growing process. The growing surface is pretreated by evap-orating ferric nitrate solution to deposit an iron compound. A methane gas is passed over the surface while heating at a temperature sufficient to decompose the methane. During an initial period, the gas is formulated by diluting natural gas with hydrogen so that the prepyrolysis methane concentration is between 5 and 15 volume percent. As used herein, methane concentration is designated by reference to the concentration in the formulated gas prior to heating to pyrolytic temperatures, it being understood that pyrolysis reduces the methane concentration by producing other carbonaceous species. This gas stream may commence either while the surface is heating to a predetermined reaction temperature or after the temperature has been achieved. In either event, the iron compound on the growing surface, when exposed to the hydrogen-base gas at elevated temperature, decomposes to form minute ferrous particles that are suitable nuclei. The nuclei react with carbon derived from the methane to produce long, thin cylindrical carbon filaments that project from the surface.
After the filaments have achieved ultimate length, the methane concentration is increased to grow the microscopic filaments radially and form macroscopic fibers. During this step, the gas phase suitably ~ ~.

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contains at least 25 volume percent methane and ispreferably undiluted natural gas. The flow of enriched gas is continued for a time sufficient to grow fibers of a desired diameter, which diameter is preferably 5 to 15 microns for fibers intended for use as plastic filler.
The yield of product fibers is optimized by maximizing the number and length of filaments during the initial step, since the subsequent thickening step does not significantly increase the number or length of the filaments. The reaction of the nuclei and the pyrolytic carbon to grow the filaments depends upon many reaction parameters including temperature and gas flow rate. However, in accordance with this invention, it has been found that the filament-forming reaction is particularly sensitive to the methane concentration in the initial gas. If the methane is too rich, the number and average length of filaments is reduced, presumably because excess carbon prematurely terminates the filament-forming reaction. On the other hand, if the methane concentration is too lean, carbon is not supplied at a rate sufficient to sustain the reactions and achieve maximum length.
In general, a prepyrolysis methane concentra-~5 tion between 5 and 15 volume percent produces abundantfilaments o~ suitable length for forming the product fibers. It is believed that, for a predetermined temperature, there is a specific methane concentration that is particularly conducive to the filament-forming reactions. For example, at 1050C, the optimum methane concentration is found to be about 11 percent.
However, the optimum concentration is sensitive to ~ .

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temperature and other reaction parameters. Further, the temperature and other reaction parameters may vary, for example, even between different regions of a growing surface. In one aspect of this invention, the methane concentration is varied over a range intended to provide an optimum concentration for a plurality of reaction conditions, including temperature fluctua-tions. Thus, for a reaction temperature within a preferred range between about 1000C and 1100C, the methane concentration may be swept from a value below 10 volume percent to above 12 volume percent, and more preferably from below 9 volume percent to above 13 volume percent.
Once nucleated, filament formation is lS completed within a short time. Continued exposure to the gas stream containing methane within the range conducive to filament formation does not thicken the filaments at an appreciable rate, even for periods of two hours or more. In accordance with this invention, the methane concentration in the gas stream is increased in a second step to radially enlarge the filaments into fibers. The diameter of the product fibers is related to the duration of this second step.
However, the length is not significantly increased. In general, a concentration greater than about 25 percent thickens the fibers at a suitable rate. Higher methane concentrations are preferred to maximize the rate of carbon deposition and thereby to minimize the time required to achieve a desired diameter~ Thus, regu-lation of the methane concentration in accordance withthis invention not only maximizes the number and length of precursor filaments, and thus the yield and length of product fibers, but also reduces the time required to produce fibers o~ a particular diameter, thereby reducing the overall reac-tion time.
Detailed Description of the Inventioll The method of this invention is illustrated by the following examples.

Example I
Graphite fibers were grown wi-thin a cylin-drical tubular mullite reactor having a gas inlet at one end and a gas outlet at the opposite end. A
longitudinal midsection of the reactor was enclosed within a coaxial cylindrical furnace such that the reactor ends extended beyond the furnace for making gas line connections thereto. The furnace had a helical electrical resistance heating element encompassing the midsection for heating the midsection to reaction temperature. The reactor inner diameter was about 52 millimeters. The midsection within the furnace was about 70 centimeters.
Fibers were grown on an alumina coupon inserted into the reactor midsection such that a surface of the coupon was exposed to the gas therein.
Prior to insertion, the coupon surface was pretreated ~5 by applying a 1.5 M aqueous ferric nitrate solution and drying to deposit an iron salt thereon.
A mixture of natural gas and dry hydrogen was delivered to the reactor through the inlet. Gas was exhausted from the reactor outlet, thereby establishing a gas stream through the reactor at slightly above atmospheric pressure. Bottled natural gas was employed from Airco, Inc. under the designation methane grade .:

1.3 and was about 96 volume percent methane. The flow rate of natural gas through the reactor was adjusted to 48 cubic centimeters per minute (cc/min)O The hydrogen flow rate was adjusted to about 452 cc/min. Thus, the methane concentration in the gas stream was estima-ted to be about 9.2 volume percent.
After air had been purged from the reactor, the furnace was heated, whereupon the reactor midsec-tion and the gas therein was heated at a rate of about 10 7C per minute to a temperature of 1130C and main-tained a~ that temperature. The flow of the 9.2 per-cent methane gas was continued for about one hour.
Thereafter, the natural gas flow rate through the re-actor was increased to 380 cc/min and the hydrogen flow rate was increased to 995 cc/min, so that the methane concentration was increased to about 28 volume percent.
After about one hour, the furnace was shut off and the reactor was cooled to room temperature. Although gas flow was discontinued during cooling, the reactor was not opened to air to avoid oxidation of the hot fibers.
An abundance of graphite fibers was found on the coupon surface. The average fiber length was about 1.5 centi-meters, although numerous fibers as long as about 3 centimeters were found. The average diameter was about 10 microns. The fibers were considered comparable to those described in United States Patent No. 4,391,787 and were suitable for use as plastic filler.

Example II
The tubular mullite reactor and the electric-al furnace were similar to Example I except that the reactor inner diameter was 19 millimeters and the hsated midsection was about 30 centimeters long. An air-purgable antechamber was provided adjacent the re-actor outlet for introducing the coupon into the reac-tor while avoiding air contamination. The reactor was heated to about 1050C while passing argon gas there-through. After the reaction temperature had been achieved, the alumina coupon was inserted into the hot zone of the reactor from the antechamber. The cGupon surface had been doped using 0.15 M ferric nitrate solution in a manner similar to Example I. After the coupon was positioned near the middle of the reactor hot zone, argon gas flow into the reactor was discon-tinued, and the flow of a dilute methane gas was initiated. Methane of high purity was premixed with, by volume, 1 percent nitrogen and 2 percent ethane to produce a formulation representative of commercial grade natural gas, but having a controlled composition to permit evaluation of the method of this invention without concerns for variations in commercial natural gas composition. The synthesized natural gas flowed into the reactor at about 4.4 cc/min and was diluted by hydrogen introduced at a rate of about 35.6 cc/min.
Thus, the methane concentration in the gas stream was estimated to be about 10.7 volume percent. This gas flow was continued for about 20 minutes, which time was deemed sufficient to permit filaments to sprout and grow to maximum length. Thereafter, the flow of hydrogen through the reactor was discontinued, and the flow rate for the synthesized natural gas was increased to about 40 cc/min for about 40 minutes. Gas flow through the reactor was then discontinued and the reactor was cooled. Examination of the coupon revealed . ..
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an abundance of graphite fibers having an average fiber length of about 4 millimeters and an average diameter of about 10 microns.

Example III
In this example, the prepyrolysis methane concentration in the gas stream was varied during the filament-forming stage over a suitable range to optimize fiber growth despite variations in reaction conditions.
The apparatus and method were substantially as in Example II except for the following differences.
The coupon surface was doped with O.lM ferric nitrate solution. After the reactor had bsen heated to about 1050C, the flow of dilute methane gas was commenced.
Initially, the gas entering the reactor consisted of 3.6 cc/min synthesized natural gas and 36.~ cc/min hydrogen, corresponding to a methane concentration of about 8.7 percent. The gas formulation was varied over a period of about one-half hour by uniformly increasing the natural gas flow rate and concurrently decreasing the hydrogen flow rate, so that the total gas flow rate remained substantially constant. After one-half hour, the gas flowing into the reactor consisted of 5.4 cc/min natural gas and 34.~ cc/min hydrogen, corre-sponding to a methane concentration of about 13.1 volume percent. Thereafter, the natural gas was passed undiluted into the furnace at a rate of about 40 cc/min for about 15 minutes. The product fibers were approximately 3 to 4 microns in diameter.

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Example IV
Example III was repeated, except that during the filament-forming step the initial gas consisted of 4 cc/min synthesized natural gas and 36 cc/min hydrogen, corresponding to a prepyrolysis methane concentration of 9.7 volume percent. The gas composition was uniformly adjusted to 4.8 cc/min natural gas and 35.2 cc/min hydrogen over one-half hour. Thereafter, undiluted natural gas was flowed into the furnace to produce the fibers.

As illustrated in these examples, the method of this invention comprises a preferred first step during which methane diluted with hydrogen interacts with the ferric nitrate deposit to form thin, long microscopic filaments. At the elevated temperature, the hydrogen-base gas is believed to reduce the ferric nitrate deposit and form minute iron particles. These particles interact with pyrolytic carbon to grow the filaments. Hydrogen is preferred for the diluent to assist in reducing the ferric nitrate deposit. Also, since hydrogen is also a major byproduct of methane pyrolysis, the presence of a large hydrogen proportion may aid in regulating methane pyrolysis in accordance with well known chemical principles to prevent uncontrolled sooting.
Once nucleated, the filaments lengthen at a very rapid rate. However, this lengthening ceases after only a short time for reasons that are not fully understood. It is believed that filament formation is substantially completed within a few minutes, although .

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the first step is preferably extended to assure maximum opportunity for filament growth.
The filaments Eormed in the first step have submicron diameters, but are thickened into fibers in a subsequent step. Thus, each produc-t fiber is derived from a filament, although only a fraction of the to-tal number of filaments resists breakage and is suitably oriented and lenthened so as to mature into fibers.
Since the thickening step does not significantly add to the length or produce additional fibers, it is useful to consider the yield of fibers as being the total length of fibers per growing surface area, which in turn is related to the population and length of the precursor filaments. It has been found that the methane concentration during the filament-forming step critically affects the fiber yield.
The optimum methane concentration depends upon the reaction temperature. At 1050C, the prepyrolysis methane concentration that produces an optimum fiber yield is about 11 volume percent.
Deviation from the optimum value reduces yield but may produce suitable results. In Example II, the reaction temperature was held constant throughout the fiber growing process. Example II was repeated at different reaction temperatures, while varying methane concentration to determine the optimum concentration at each temperature. At 1000C, the optimum methane concentration was found to be about 12.5 volume percent. At 1100C, the optimum was about 8 volume percent. At 1150C, the optimum was about 5.5 volume percent. Above 1200C and below 950C few fibers were formed under the conditions of Example II. In general, .

~2~ 6 a methane concentration between about 5 and 15 volume percent produces precursor filaments sufficient to form a high density of suitably long fibers.
The practice of -this invention is not limited to maintaining a constant prepyrolysis methane concentration during the filament formation step, but may advantageously be carried out by varying the methane concentration over a suitable range to obtain optimum fiber yield despite fluctuations in temperature or differences in other reaction conditions. Reaction conditions may vary not only over the time of the reaction, but also between different regions within the reactor. At 1050C, it is believed that filament growth is optimized using about 11 volume percent methane, as in Example II. However, a high yield of ibers may be obtained with methane concentrations within a preferred range between 9 and 13 volume percent. Thus, as illustrated in Example III, the methane concentration may be gradually increased to ~0 sweep over the preferred range~ The prepyrolysis methane concentration may be adjusted initially to a value o less than 9 percent and gradually increased to a value greater than 13 percent. Alternately~, the methane concentration may be suitably swept over a narrower range from below to above the optimum methane concentration, as in Example IV. The rate at which the methane concentration is increased is suitably slow to permit filaments to form, which occurs rapidly when optimum conditions are achieved. In general, sweeping the methane concentration over a period of time of between about 10 and 30 minutes is sufficient~

Preferred conditions comprise a temperature between about 1000C and 1100C and a methane concentration between about 8 and 13 volume percent.
Although Example II comprises isothermal reactions, it is believed that filaments may be formed at tempera-tures as low as about 600C, although such low temperatures evidently are not sufficient to thicken the filaments. Thus, commencing methane gas flow during warm-up, as in Example I, may accelerate filament formation, particularly since the filament lengthening reaction may be favored at lower tempera-tures. It has been found that fibers grow within the reactor after the gas has been heated at the reaction temperature 10 to 20 seconds. Optimum growth occurs after the gas is heated for about 15 seconds.
The relatively low methane concentration employed in the first step to promote filament formation is not sufficient to enlarge the filaments radially at a rate sufficient to form the fibers within a practical time. In Example II, continued exposure to 10.7 volume percent methane gas at 1050C for times as long as two hours does not significantly increase the diameter. Thus, the method of this invention comprises a second step wherein methane concentration in the gas stream is increased. At this increased concentration, pyrolysis produces abundant carbonaceous species that suitably deposit on the peripheral surfaces to thicken the filaments into fibers~ In general, it is found that a methane concentration greater than about 25 volume percent thickens at an appreciable rate.
However, it is preferred to maximize the methane concentration in the gas phase, for example, by using , ' :

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, undiluted natural gas, to improve efficiency and maximize the radial growth rate. For a particular methane concentration in the second step, it is believed that the average diameter of the product fibers increases linearly as a function of time, so that the diameter is conveniently determined by the duration of the second step. In general, fiber diameters of between 5 and 100 microns are suitable for plastic filler, with fibers having diameters between 5 and 15 microns being preferred.
The rate at which filaments thicken into fibers is also dependent upon other reaction parameters including temperature and flow rate. In general, the flow rate may be increased during the second step to increase the rate at which pyrolytic carbon is supplied to the growing surface. Also, while temperatures as low as 600C are suitable for forming filaments, temperatures near 1200C or higher enhance the thickening reactions.
In the described embodiments the ceramic surface was initially doped with ferric nitrate solution. It is believed that ferric nitrate deposit decomposes at moderately elevated temperatures to a mixture of iron oxides, which iron oxides thereafter further decompose at elevated temperatures in the presence of a hydrogen-base reducing gas to form metallic nuclei suitable for forming filaments.
However, nuclei derived from other sources may be substituted. For example, fibers have been grown using nuclei derived from submicron magnetite particles.
Also, iron particles derived from thermal decomposition of iron carbonyl produce fibers. Iron particles having diameters less than 0.1 micron are commercially available and are suitable nuclei.
While this invention has been described in terms of certain embodiments thereof, it is not intended to be limited to the above description, but only to the extent set forth in the claims that follow.

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Claims (6)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A methane pyrolysis process for growing graphite fibers on a suitably nucleated ceramic surface, said process comprising flowing a hydrogen-base gas comprising about 5 to 15 volume percent methane over said surface while heating to decompose the methane to form microscopic carbon filaments that project from the surface, and thereafter flowing a gas containing greater than 25 volume percent methane over said surface while heating to decompose the methane to thicken the filaments into fibers.
2. A methane pyrolysis process for manu-facturing graphite fibers by growing the fibers on a surface of a ceramic substrate bearing suitable iron-base nuclei, said process comprising flowing a hydrogen gas stream comprising a prepyrolysis methane concentration between about 5 and 15 volume percent over the surface while heating to a temperature between about 600°C and 1200°C to decompose the methane in the gas stream and grow microscopic elongated carbon filaments on the surface that project therefrom, and thereafter passing a gas stream comprising a prepyrolysis methane concentration greater than 25 volume percent over said surface while heating at a temperature between about 950°C and 1200°C to decompose the methane in the gas stream and thicken the filaments into fibers.
3. A methane pyrolysis process for manu-facturing graphite fibers by growing the fibers on a surface of a ceramic substrate bearing an iron oxide deposit reducible to form suitable iron-base nuclei, said process comprising flowing a gas stream formed by diluting natural gas with hydrogen over the surface while heating between about 950°C and 1200°C to decompose the methane in the gas stream and grow microscopic elongated carbon filaments on the surface that project therefrom, said gas stream having a prepyrolysis methane concentration between about 5 and 15 volume percent, and thereafter passing a gas stream comprising natural gas and having a prepyrolysis methane concentration above 25 volume percent over said surface while continuing to heat at a temperature within said range for a time sufficient to thicken the filaments into fibers.
4. A natural gas pyrolysis process for manufacturing graphite fibers by growing the fibers on a surface of a ceramic substrate bearing an iron oxide deposit of the type formed by evaporation of a ferric nitrate solution, said process comprising passing a gas stream over the growing surface while heating to a methane pyrolysis temperature, said gas stream initially comprising methane from a natural gas source and diluted with hydrogen to a concentration between about 8 and 13 volume percent, said gas stream and growing surface being heated at a temperature between about 1000°C and 1100°C, whereupon carbon derived from the methane interacts with iron-base nuclei derived from the iron oxide to form carbon filaments that project from the surface, and passing a substantially undiluted natural gas stream in contact with the filament-bearing surface at a temperature within said range and continuing for a time sufficient to radially grow the filaments into fibers having diameters between about 5 and 15 microns.
5. A methane pyrolysis process for manufacturing graphite fibers and comprising passing a methane-containing stream over a suitably nucleated ceramic surface while heating the gas at a temperature sufficient to decompose the methane to form carbon filaments that project from said surface and thereafter thicken the filaments into the product fibers, said process further comprising initially passing over said surface a predominantly hydrogen gas stream having a prepyrolysis methane concentration less than the optimum filament-forming concentration for said temperature, gradually increasing the prepyrolysis methane concentration in said gas stream to above the optimum filament-forming concentration for said temperature over a time sufficient to form said filaments, and thereafter further increasing the prepyrolysis methane concentration in said gas stream to above 25 volume percent to thicken the filaments into the fibers.
6. A methane pyrolysis process for manufacturing graphite fibers by growing the fibers on a ceramic surface bearing a suitable iron nuclei, said process comprising passing a methane-containing gas stream over the surface while heating at a predetermined temperature between about 1000°C and 1100°C to decompose the methane, said process further comprising initially passing a gas stream over the surface that comprises a natural gas source blended with hydrogen and having a prepyrolysis methane concentration less than 9 volume percent, gradually increasing the methane concentration in said stream to a prepyrolysis concentration above 12 volume percent over a period of between 10 and 30 minutes, whereupon nascent carbon interacts with the iron nuclei derived from said iron oxide to form carbon filaments that project from the surface, and thereafter passing a substantially undiluted natural gas stream in contact with the filaments on said surface for a time sufficient to radially grow the filaments into fibers having diameters between about 5 and 15 microns.
CA000485059A 1984-08-20 1985-06-25 Regulation of pyrolysis methane concentration in the manufacture of graphite fibers Expired CA1245816A (en)

Applications Claiming Priority (4)

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US64257484A 1984-08-20 1984-08-20
US642,574 1984-08-20
US685,046 1984-12-21
US06/685,046 US4565684A (en) 1984-08-20 1984-12-21 Regulation of pyrolysis methane concentration in the manufacture of graphite fibers

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EP (1) EP0175459B1 (en)
AU (1) AU4559885A (en)
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CA (1) CA1245816A (en)
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Families Citing this family (96)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2564110B1 (en) * 1984-05-10 1986-09-05 Lorraine Carbone PROCESS FOR PRODUCING VAPO-DEPOSITED CARBON FIBERS FROM METHANE
US4749557A (en) * 1984-12-04 1988-06-07 General Motors Corporation Graphite fiber growth employing nuclei derived from iron pentacarbonyl
US5165909A (en) 1984-12-06 1992-11-24 Hyperion Catalysis Int'l., Inc. Carbon fibrils and method for producing same
US5171560A (en) * 1984-12-06 1992-12-15 Hyperion Catalysis International Carbon fibrils, method for producing same, and encapsulated catalyst
US5707916A (en) * 1984-12-06 1998-01-13 Hyperion Catalysis International, Inc. Carbon fibrils
US4855091A (en) * 1985-04-15 1989-08-08 The Dow Chemical Company Method for the preparation of carbon filaments
US5424126A (en) * 1985-12-19 1995-06-13 General Motors Corporation Thin inorganic fibers
US5210116A (en) * 1988-01-19 1993-05-11 Yazaki Corporation Resin composite material containing graphite fiber
JPH02167898A (en) * 1988-12-21 1990-06-28 Mitsubishi Petrochem Co Ltd Production of graphite whisker
ZA907803B (en) * 1989-09-28 1991-07-31 Hyperion Catalysis Int Electrochemical cells and preparing carbon fibrils
US5413773A (en) * 1990-10-09 1995-05-09 General Motors Corporation Method for forming carbon filters
US5024818A (en) * 1990-10-09 1991-06-18 General Motors Corporation Apparatus for forming carbon fibers
US5246794A (en) * 1991-03-19 1993-09-21 Eveready Battery Company, Inc. Cathode collector made from carbon fibrils
US5639429A (en) * 1992-02-24 1997-06-17 Consejo Superior Investigaciones Cientificas Reactor for the production of short ceramic fibers from gas
US5643670A (en) * 1993-07-29 1997-07-01 The Research Foundation Of State University Of New York At Buffalo Particulate carbon complex
US5690997A (en) * 1993-10-04 1997-11-25 Sioux Manufacturing Corporation Catalytic carbon--carbon deposition process
US6746626B2 (en) 1994-06-20 2004-06-08 Sgl Technic Inc. Graphite polymers and methods of use
EP0758028B1 (en) * 1995-07-10 2002-09-11 Research Development Corporation Of Japan Process of producing graphite fiber
JP2001507988A (en) 1997-06-02 2001-06-19 ハイトコ カーボン コムポージッツ インコーポレイテッド High performance filter
US6390304B1 (en) 1997-06-02 2002-05-21 Hitco Carbon Composites, Inc. High performance filters comprising inorganic fibers having inorganic fiber whiskers grown thereon
US6155432A (en) 1999-02-05 2000-12-05 Hitco Carbon Composites, Inc. High performance filters based on inorganic fibers and inorganic fiber whiskers
US20070138702A9 (en) * 1999-11-12 2007-06-21 General Electric Company Molded, filled polymer compositions with reduced splay and a method of making
US6627704B2 (en) 1999-12-01 2003-09-30 General Electric Company Poly(arylene ether)-containing thermoset composition, method for the preparation thereof, and articles derived therefrom
US6352782B2 (en) * 1999-12-01 2002-03-05 General Electric Company Poly(phenylene ether)-polyvinyl thermosetting resin
US6905637B2 (en) 2001-01-18 2005-06-14 General Electric Company Electrically conductive thermoset composition, method for the preparation thereof, and articles derived therefrom
US7235192B2 (en) * 1999-12-01 2007-06-26 General Electric Company Capped poly(arylene ether) composition and method
US6878782B2 (en) * 1999-12-01 2005-04-12 General Electric Thermoset composition, method, and article
US6812276B2 (en) * 1999-12-01 2004-11-02 General Electric Company Poly(arylene ether)-containing thermoset composition, method for the preparation thereof, and articles derived therefrom
US6521703B2 (en) 2000-01-18 2003-02-18 General Electric Company Curable resin composition, method for the preparation thereof, and articles derived thereform
DE10196589T1 (en) 2000-08-14 2003-07-10 World Properties Inc Thermosetting composition for components of an electrochemical cell and method for their production
US6858349B1 (en) 2000-09-07 2005-02-22 The Gillette Company Battery cathode
US6500895B1 (en) 2000-10-13 2002-12-31 General Electric Company Thermoplastic blend comprising poly(arylene ether) and polyamide
US6353050B1 (en) 2000-10-13 2002-03-05 General Electric Co. Thermoplastic blend comprising poly(arylene ether) and polyamide
US6660794B2 (en) 2000-12-28 2003-12-09 General Electric Company Glass-filled poly(arylene ether)-polyolefin composition and articles derived therefrom
US6627701B2 (en) * 2000-12-28 2003-09-30 General Electric Company Method for the preparation of a poly(arylene ether)-polyolefin composition, and composition prepared thereby
US6815491B2 (en) 2000-12-28 2004-11-09 General Electric Reinforced thermoplastic composition and articles derived therefrom
US6545080B2 (en) 2000-12-28 2003-04-08 General Electric Company Glass-filled poly(arylene ether)-polyolefin composition and articles derived therefrom
DE10295503T5 (en) * 2001-01-19 2005-09-08 World Properties, Inc., Lincolnwood Apparatus and method for electrochemical cell components
US7138203B2 (en) * 2001-01-19 2006-11-21 World Properties, Inc. Apparatus and method of manufacture of electrochemical cell components
US6878781B2 (en) * 2001-03-27 2005-04-12 General Electric Poly(arylene ether)-containing thermoset composition in powder form, method for the preparation thereof, and articles derived therefrom
US6593391B2 (en) * 2001-03-27 2003-07-15 General Electric Company Abrasive-filled thermoset composition and its preparation, and abrasive-filled articles and their preparation
US20020172867A1 (en) * 2001-04-10 2002-11-21 Anglin David L. Battery cathode
US6620359B1 (en) 2001-04-11 2003-09-16 Sgl Technic, Inc. Water based method of making expanded graphite the product produced and expanded graphite polymeric pellets
US6689835B2 (en) 2001-04-27 2004-02-10 General Electric Company Conductive plastic compositions and method of manufacture thereof
US6872777B2 (en) 2001-06-25 2005-03-29 General Electric Poly(arylene ether)-polyolefin composition, method for the preparation thereof, and articles derived therefrom
US7022777B2 (en) * 2001-06-28 2006-04-04 General Electric Moldable poly(arylene ether) thermosetting compositions, methods, and articles
US6528572B1 (en) 2001-09-14 2003-03-04 General Electric Company Conductive polymer compositions and methods of manufacture thereof
US7022776B2 (en) * 2001-11-07 2006-04-04 General Electric Conductive polyphenylene ether-polyamide composition, method of manufacture thereof, and article derived therefrom
US6734262B2 (en) 2002-01-07 2004-05-11 General Electric Company Methods of forming conductive thermoplastic polyetherimide polyester compositions and articles formed thereby
US6810333B2 (en) 2002-02-12 2004-10-26 General Electric Company Method, system, storage medium, and data signal for supplying a multi-component composition
US20030215588A1 (en) * 2002-04-09 2003-11-20 Yeager Gary William Thermoset composition, method, and article
US6894102B2 (en) * 2002-05-20 2005-05-17 General Electric Syndiotactic polystyrene blends
US20060108567A1 (en) * 2002-07-23 2006-05-25 Charati Sanjay G Conductive poly (arylene ether) compositions and methods of making the same
US8999200B2 (en) * 2002-07-23 2015-04-07 Sabic Global Technologies B.V. Conductive thermoplastic composites and methods of making
WO2004026962A2 (en) * 2002-09-20 2004-04-01 General Electric Company Underhood components
CN1732217A (en) * 2002-12-23 2006-02-08 陶氏环球技术公司 Electrically conductive polymerized macrocyclic oligomer carbon nanofiber compositions
WO2004076541A2 (en) 2003-02-21 2004-09-10 General Electric Company Translucent thermoplastic composition, method for making the composition and articles molded there from.
US20040211942A1 (en) * 2003-04-28 2004-10-28 Clark Darren Cameron Electrically conductive compositions and method of manufacture thereof
US20040232389A1 (en) * 2003-05-22 2004-11-25 Elkovitch Mark D. Electrically conductive compositions and method of manufacture thereof
US20050171266A1 (en) * 2003-06-10 2005-08-04 Matthijssen Johannes G. Filled compositions and a method of making
US20040262581A1 (en) * 2003-06-27 2004-12-30 Rodrigues David E. Electrically conductive compositions and method of manufacture thereof
EP1654740A1 (en) * 2003-08-08 2006-05-10 General Electric Company Electrically conductive compositions comprising carbon nanotubes and method of manufacture thereof
US7026432B2 (en) * 2003-08-12 2006-04-11 General Electric Company Electrically conductive compositions and method of manufacture thereof
US7354988B2 (en) * 2003-08-12 2008-04-08 General Electric Company Electrically conductive compositions and method of manufacture thereof
US7309727B2 (en) * 2003-09-29 2007-12-18 General Electric Company Conductive thermoplastic compositions, methods of manufacture and articles derived from such compositions
US20050070658A1 (en) * 2003-09-30 2005-03-31 Soumyadeb Ghosh Electrically conductive compositions, methods of manufacture thereof and articles derived from such compositions
US7205342B2 (en) * 2003-10-10 2007-04-17 General Electric Company Poly(arylene ether) composition and method of molding
US7022765B2 (en) * 2004-01-09 2006-04-04 General Electric Method for the preparation of a poly(arylene ether)-polyolefin composition, and composition prepared thereby
US20050228109A1 (en) * 2004-04-07 2005-10-13 Tapan Chandra Thermoplastic compositions with improved paint adhesion
US6969745B1 (en) 2004-06-30 2005-11-29 General Electric Company Thermoplastic compositions
US7462656B2 (en) * 2005-02-15 2008-12-09 Sabic Innovative Plastics Ip B.V. Electrically conductive compositions and method of manufacture thereof
US20060280938A1 (en) * 2005-06-10 2006-12-14 Atkinson Paul M Thermoplastic long fiber composites, methods of manufacture thereof and articles derived thererom
US20070049690A1 (en) * 2005-08-29 2007-03-01 Pravin Borade Impact modified poly(arylene ether)/polyester blends and method
US20070276082A1 (en) * 2006-05-24 2007-11-29 Kim Balfour Poly(arylene ether) composition, method, and article
US20070276067A1 (en) * 2006-05-24 2007-11-29 Kim Balfour Poly(arylene ether) composition, method, and article
US8536272B2 (en) * 2007-07-12 2013-09-17 Sabic Innovative Plastics Ip B.V. Thermoplastic poly(arylene ether)/polyester blends and method of making
US8092717B2 (en) 2007-07-12 2012-01-10 Sabic Innovative Plastics Ip B.V. Thermoplastic poly(arylene ether) / polyester blends and articles thereof
US7534374B2 (en) * 2007-08-28 2009-05-19 Sabic Innovative Plastics Ip B.V. Injection molded article and composition for the preparation thereof
US20090146109A1 (en) 2007-12-06 2009-06-11 Sabic Innovative Plastics Ip Bv Thermoplastic poly(arylene ether)/polyamide blends and method of making
US8795557B2 (en) 2008-03-31 2014-08-05 Sabic Innovative Plastics Ip B.V. Flame resistant polyphthalamide/poly(arylene ether) composition
US8257613B2 (en) * 2008-04-09 2012-09-04 Sabic Innovative Plastics Ip B.V. Filled compositions and a method of making
US7947201B2 (en) * 2008-09-30 2011-05-24 Sabic Innovative Plastics Ip B.V. Poly(arylene ether)/polyamide composition and method of making
US8137592B2 (en) 2010-05-04 2012-03-20 Sabic Innovative Plastics Ip B.V. Method of incorporating an additive into a polymer composition and dispersion used therein
US8377337B2 (en) 2010-05-04 2013-02-19 Sabic Innovative Plastics Ip B.V. Method of incorporating an additive into a polyamide-poly(arylene ether) composition, composition prepared thereby, and article comprising the composition
US9362560B2 (en) 2011-03-08 2016-06-07 GM Global Technology Operations LLC Silicate cathode for use in lithium ion batteries
US9281515B2 (en) 2011-03-08 2016-03-08 Gholam-Abbas Nazri Lithium battery with silicon-based anode and silicate-based cathode
US8663840B2 (en) 2011-04-12 2014-03-04 GM Global Technology Operations LLC Encapsulated sulfur cathode for lithium ion battery
US8557158B2 (en) 2011-08-23 2013-10-15 Sabic Innovative Plastics Ip B.V. Molded article having enhanced aesthetic effect and method and system for making the molded article
KR101994384B1 (en) 2012-05-30 2019-06-28 엑사테크 엘.엘.씨. Plastic assembly, methods of making and using the same, and articles comprising the same
US9809740B2 (en) 2012-10-10 2017-11-07 Baker Hughes, A Ge Company, Llc Nanoparticle modified fluids and methods of manufacture thereof
US8592549B1 (en) 2012-12-05 2013-11-26 Sabic Innovative Plastics Ip B.V. Polyamide composition, method, and article
US8865279B2 (en) 2013-03-04 2014-10-21 Sabic Global Technologies B.V. Reinforced polyphthalamide/poly(phenylene ether) composition
WO2016196472A1 (en) 2015-05-29 2016-12-08 Sabic Global Technologies B.V. Honeycomb paper
KR20200024833A (en) 2017-06-30 2020-03-09 사빅 글로벌 테크놀러지스 비.브이. Articles comprising reinforcement paper, method of making reinforcement paper and reinforcement paper
EP3822066A1 (en) 2019-11-14 2021-05-19 SABIC Global Technologies B.V. Thermoplastic composite materials having reduced voids and methods of forming the same
DE102021206600A1 (en) 2021-06-25 2022-12-29 Cellcentric Gmbh & Co. Kg Process for producing carbon and fuel cell system

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2796331A (en) * 1954-06-09 1957-06-18 Pittsburgh Coke & Chemical Co Process for making fibrous carbon
US3378345A (en) * 1965-03-22 1968-04-16 Union Carbide Corp Process for producing pyrolytic graphite whiskers
US3411949A (en) * 1965-08-13 1968-11-19 Air Force Usa Method and apparatus for the manufacture of pyrolytic fibers
US3664813A (en) * 1969-07-17 1972-05-23 Glass John P Method for making graphite whiskers
US4014980A (en) * 1972-07-27 1977-03-29 Kureha Kagaku Kogyo Kabushiki Kaisha Method for manufacturing graphite whiskers using condensed polycyclic hydrocarbons
US4391787A (en) * 1980-07-18 1983-07-05 General Motors Corporation Method for growing graphite fibers
CA1175616A (en) * 1981-01-05 1984-10-09 Exxon Research And Engineering Company Production of iron monoxide and carbon filaments therefrom

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