EP0472666A1 - Cvd grown transition metal carbide and nitride whiskers - Google Patents
Cvd grown transition metal carbide and nitride whiskersInfo
- Publication number
- EP0472666A1 EP0472666A1 EP90911429A EP90911429A EP0472666A1 EP 0472666 A1 EP0472666 A1 EP 0472666A1 EP 90911429 A EP90911429 A EP 90911429A EP 90911429 A EP90911429 A EP 90911429A EP 0472666 A1 EP0472666 A1 EP 0472666A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- whiskers
- process according
- metal
- reaction chamber
- gases
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/60—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape characterised by shape
- C30B29/62—Whiskers or needles
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B25/00—Single-crystal growth by chemical reaction of reactive gases, e.g. chemical vapour-deposition growth
- C30B25/005—Growth of whiskers or needles
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/36—Carbides
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/38—Nitrides
Definitions
- the present invention generally relates to a process for producing single crystal metal carbide, nitride, or carbonitride whiskers and, in particular, to a process for producing metal carbide, nitride, or carbonitride whiskers by a chemical vapor deposition process and the products thereof.
- Whiskers are minute, high purity, single crystal fibers having strengths approaching interatomic bonding forces and improved resistance to high temperatures and greater toughness when compared to polycrystalline fibers. Due to their high modulus of elasticity, hardness, strength, and chemical stability, single crystal whiskers of such materials as carbides or nitrides of titanium, zirconium, hafnium, niobium, tantalum, and tungsten are candidate materials to reinforce and toughen metal, ceramic and glass matrix composites. Whiskers may be grown by a number of processes including chemical vapor deposition (CVD) .
- CVD chemical vapor deposition
- Typical temperatures in such reactors range from about 800 degrees to 1400 degrees C.
- the reactor is first flushed with hydrogen gas.
- reactant gases typically in a molar ratio of carbon or nitrogen to metal of about 1:1, are flowed through the heated reactor to form whiskers on the growth substrate.
- the choice of the growth substrate materials can be critical to the formation and type of whiskers (see Wokulski et al., J. Crystal Growth, 62, pp. 439- 446 (1983)) .
- the use of graphite as a growth substrate has been shown to produce a variance in the C/Ti mole ratio.
- growth substrates of tungsten, molybdenum, and iron while not affecting the growth of the whiskers, do not produce significant numbers of whiskers.
- iron- based growth substrates react vigorously with the reactants for producing the whiskers.
- VLS vapor- liguid-solid
- a liquid catalyst is used in place of a solid substrate.
- the catalyst must display the ability, when molten, to take into solution the elements and compounds necessary to produce the desired whiskers.
- transition metal and alloy powders have been satisfactory.
- the reaction for the VLS process takes place at approximately 1400 degrees C or above the melting point of the catalyst.
- the whiskers which can be grown by this process have been limited to those having a reaction temperature equal to or greater than the melting point of the catalyst.
- residual catalyst may remain with the whiskers thereby adversely affecting the physical properties of the subsequent composite article. Attempts to remove the residual catalyst by chemical or physical means have resulted in damage to the whiskers.
- U.S. Patent No. 4,686,197 issued to Elvin, discloses a process for demetallizing a petrochemical catalyst with chlorine gas at approximately 350 degrees C. According to Elvin, the process successfully removed Ni and/or V from a contaminated catalyst.
- U.S. Patent No. 4,492,767 issued to Fung, discloses a process for reactivating a coked petrochemical catalyst which includes a halide pretreatment step at approximately 300 to 540 degrees C and a halogen redispersion step with a mixture of elemental halogen and water vapor at approximately 500 to 540 degrees C.
- the metal of interest in Fung is iridium and it is directed to redispersing the iridium rather than removing it from the catalyst.
- the present invention solves the aforementioned problems associated with the prior art by providing an improved process for producing metal carbide, nitride, or carbonitride whiskers of controlled dimensions, morphology, and quality by a CVD/VLS process.
- the present invention is based on the surprising discovery that it is not necessary to be above the melting point of a powdered metal catalyst in order for whisker growth to occur. It is postulated that the catalyst combines with the reactant gases to produce a lower melting point eutectoid composition, thereby allowing whisker growth to occur.
- the reaction chamber includes one or more growth substrate surfaces having nickel or high nickel alloy powder dispersed onto aluminum oxide plates to provide catalyzing and supporting substrates for nucleation and growth of the whiskers.
- the melting point of the powder is approximately 1455 degrees C.
- the growth substrate surfaces are maintained at an operating temperature of about 1120 to 1225 degrees C, preferably about 1190 to 1220 degrees C.
- the process includes the steps of flushing the reaction chamber sealed from the ambient atmosphere with flowing hydrogen gas.
- the hydrogen flowing through the reaction chamber is then mixed, at about ambient pressure, with reactants comprising a metal halide gas and one or more gases selected from the group consisting of aliphatic hydrocarbon gases pyrolyzable at the operating- temperature to form free carbon.
- Nitrogen gas and/or ammonia may be substituted for or mixed with the hydrocarbon gases to produce nitride or carbonitride whiskers.
- the atomic ratios of carbon and nitrogen to metal in the incoming gases is about 0.7:1 and 20:1, respectively, and the volume ratios of hydrocarbon and nitrogen gases to hydrogen is 1:37 and 1:1.6, respectively.
- the flowing mixture of gases is maintained at a suitable linear velocity, preferably about 2-4 cm/sec, for a time sufficient- to nucleate and grow metal carbide, nitride, or carbonitride whiskers on the growth substrate material surfaces.
- Suitable hydrocarbon gases are.compounds of the formulas c n H 2 n+2' c n H 2n' or c n H 2 n- 2 ' wnere n is a positive integer of 1 to .4.
- the preferred hydrocarbon is methane.
- the whiskers are subjected to a post-growth treatment to remove the residual nickel metal catalyst used to grow the whiskers.
- the process is a two-step procedure.
- the whiskers are treated at less than 427 degrees C, preferably between 350 to 400 degrees C, with 2.8 slm of HC1 in 11.4 slm of argon gas at one atmosphere pressure for approximately one hour to convert the elemental nickel residual catalyst to NiCl 2 •
- the whiskers are then heated to at least 973 degrees C, preferably greater than 1000 degrees C, and treated with 11.4 slm of argon for one hour to cause the NiCl 2 to sublime.
- the nickel content of the treated whiskers is reduced from 1-2 wt% to 0.2 wt%, an order of magnitude reduction.
- one aspect of the present invention is to provide a process for producing metal carbide, nitride, or carbonitride whiskers comprising the steps of flushing a reaction chamber sealed from the ambient atmosphere with flowing hydrogen gas, wherein the reaction chamber includes one or more growth substrate surfaces formed from one or more materials suitable for providing catalyzing and supporting substrates for nucleation and growth of the whiskers, and wherein the growth substrate surfaces are maintained at an operating temperature suitable for growing the whiskers, and, wherein the one or more substrate materials is a high temperature material having a metal powder deposited upon a portion of its surface; and mixing with the hydrogen flowing through the reaction chamber, at about ambient pressure, reactants including one or more metal halide gases selected from the group consisting of halides of titanium, zirconium, hafnium, niobium, tantalum and tungsten and one or more gases selected from the group consisting of nitrogen, ammonia, and aliphatic hydrocarbon gases pyrolyzable at the operating temperature to form free carbon, in an atomic ratio
- Another aspect of the present invention is to provide a process for producing metal carbide, nitride, or carbonitride whiskers comprising the steps of flushing a reaction chamber sealed from the ambient atmosphere with flowing hydrogen gas, wherein the reaction chamber includes one or more growth substrate surfaces formed from one or more materials suitable for providing catalyzing and supporting substrates for nucleation and growth of the whiskers, and wherein the growth substrate surfaces are maintained at an operating temperature of about 1120 to 1225 degrees C; and mixing with the hydrogen flowing through the reaction chamber, at about ambient pressure, reactants including one or more metal halide gases selected from the group consisting of halides of titanium, zirconium, hafnium, niobium, tantalum and tungsten and one or more gases selected from the group consisting of nitrogen, ammonia, and aliphatic hydrocarbon gases pyrolyzable at the operating temperature to form free carbon, in an atomic ratio of carbon plus nitrogen to metal of about 0.7:1 to 20:1 and a volume ratio of hydrocarbon plus nitrogen or ammonia
- Still another aspect of the present invention is to provide a process for removing the residual metal catalyst from metal carbide, nitride, or carbonitride whiskers in a reaction chamber sealed from the ambient atmosphere, the chamber including one or more substrate surfaces for supporting the whiskers, comprising the steps of supplying the reaction chamber with a reactant including one or more gases selected from the group consisting of halogens, hydrogen halides, or chlorocarbons at a first operating temperature for a first predetermined time, the first operating temperature being sufficient to form a halide with the metal catalyst, and flushing the reaction chamber at a second operating temperature for a second predetermined time to remove the metal halide from the reaction chamber, the second operating temperature being sufficient to cause the metal halide to sublime.
- a reactant including one or more gases selected from the group consisting of halogens, hydrogen halides, or chlorocarbons
- Another aspect of the present invention is to provide metal carbide, nitride, or carbonitride whiskers produced by chemical vapor deposition and treated to remove the residual catalyst, the treated whiskers having substantially the same physical properties as untreated whiskers.
- the present invention may be practiced using a conventional reactor.
- One particularly suitable reactor is a model TI-100-V reactor manufactured by TI Coatings, Inc., Mt. Clemens, Michigan.
- the total volume of the reactor is approximately 1400 in 3 .
- the reactor includes inlet and outlet means in the reaction vessel to permit the flowing gas to enter and exit the vessel in such a way that gas flow is established permitting optimum contact of the flowing gases with the surface of the growth substrate.
- the growth substrate is preferably nickel powder dispersed onto aluminum oxide plates or nickel electrolytically deposited onto TiC or TiN coated aluminum oxide plates.
- the growth substrate is prepared by ultrasonically suspending nickel powder having a particle size of approximately 2 microns in isopropyl alcohol and then spraying the solution onto 72 4"x4"xl/8" aluminum oxide plates with an air gun. The plates were weighed before and after spraying and it was calculated that the substrate surfaces received approximately 2.7 gms/meter 2 of nickel powder.
- the use of aluminum oxide instead of graphite helps to eliminate an extra, uncontrollable source of carbon in the gas phase.
- the growth plates are arranged radially and axially within a support structure.
- the reactor includes conventional heating means to heat the growth substrates to the operating temperature. Typically, the operating temperature may be monitored by thermocouples disposed adjacent to the surface of the support structure. Also, as is well known in the art, the entire reactor is sealed from the ambient atmosphere to prevent contamination of the whiskers grown therein.
- metal carbide whiskers are grown on an aluminum oxide growth substrate surface on which nickel powder has been dispersed or electrolytically deposited in a reactor having a controlled atmosphere.
- the growth substrate surface is heated to an operating temperature of about 1120 to 1225 degrees C, preferably 1190 to 1220 degrees C, while being flushed with hydrogen gas at ambient pressure.
- the pressure within the reaction chamber preferably is maintained at about 1 atmosphere throughout the operation of the reactor.
- the flow of hydrogen is increased, with the addition of a suitable metal halide in an amount suitable for whisker growth.
- the atomic ratio of carbon to metal in the reactant gases is maintained at about 0.7:1 and the volume ratio of hydrocarbon to hydrogen at about 1:37.
- the flow of reactant gases is maintained, preferably at a linear velocity of about 2 cm/sec, for a time sufficient for whisker nucleation and growth, normally about 2 hours. Following the whisker growth, the flows of reactant gases are stopped, and the flow of hydrogen gas is maintained while the growth substrate surface is cooled to ambient temperature.
- the reaction chamber is flushed with an inert gas, such as argon, prior to removal of the whiskers.
- metal nitride whiskers also may be grown in the reactor, as described above, with respect to the metal carbide whiskers and the dispersed nickel on aluminum oxide growth substrate.
- the process is substantially the same as that for growing the metal carbide whiskers with the exception that the hydrocarbon for whisker growth is replaced by nitrogen gas.
- the atomic ratio of nitrogen with respect to metal is about 20:1 and the volume ratio of nitrogen to hydrogen is about 1:1.6.
- the whiskers are subjected to a post-growth treatment to remove the residual nickel catalyst used to grow the whiskers.
- the process is a two-step procedure. In the first step, the whiskers are treated at between 350 to 400 degrees C at one atmosphere pressure with 2.8 slm of HC1 in 11.4 slm of argon gas, based on a total available amount of nickel catalyst of approximately 2 gms, for approximately one hour to convert the elemental nickel residual catalyst to NiCl 2 . In the second step, the whiskers are then heated to 1000 degrees C and treated with 11.4 slm of argon for one hour to cause the NiCl 2 to sublime.
- Tables 1 and 2 shown below.
- Ni (s) + 2 HCl (g) yields NiCl 2(s) + H 2 (g)
- any of the chlorine compounds will react with free nickel to produce NiCl 2 over a wide range of temperatures.
- the hydrogen halides are particularly suitable for NiX 2 formation since the free energy values for this family of reactions become positive (i.e. non-reactive) above specific temperatures. This transition from a reactive to nonreactive region allows the reaction with nickel to be controlled by varying the temperature in the reactor.
- the hydrogen halide HCl is particularly suitable since its free energy value with respect to Tic goes positive (i.e. non-reactive) above approximately 900 degrees C.
- the rate of reaction of HCl with TiC below 900 degrees C is apparently slow enough that the whiskers are not affected.
- the transitions from reactive to nonreactive regions allow both the reactions with nickel and TiC to be controlled by varying the temperature in the reactor.
- the residual nickel catalyst content of the whiskers, produced according to the subject invention, and then treated, as discussed above, is reduced from 1-2 wt% to 0.2 wt%, an order of magnitude reduction.
- the heating and hydrogen flushing steps, and the introduction of the reactant gases are carried out as described above.
- the flowing gases enter the reaction chamber through inlet means, flow upwardly past the growth substrates, and exit the reactor through outlet means.
- the temperature in the reactor is monitored by a thermocouple.
- the reactor is then shut down, cooled and opened.
- the shape, and morphology of the whiskers were observed by a scanning electron microscope.
- the whiskers were found to vary in diameter from 1 to 5 micrometers and were straight to alternating surface morphologies on the faces parallel to the growth axis. Typical results are shown in Table 3.
- the yield of TiC whiskers was relatively independent with respect to temperature and TiCl 4 .
- lower total flow rates require an increase in the amount of TiCl 4 in order to produce an equivalent yield as higher flow rates.
- EXAMPLES 6-8 Growth of titanium nitride whiskers was carried out at about 1 atm pressure in a sealed reactor. The reactor was heated while being flushed with hydrogen at 10 slm. The hydrogen flow was then increased. Titanium tetrachloride liquid was flash evaporated at about 130 to 260 degrees C and then mixed with the hydrogen-nitrogen mixture for 2 hours for whisker growth. The atomic ratio of nitrogen to metal in the reactant gases was maintained at about 20:1 and the volume ratio of nitrogen to hydrogen at about 1:1.6. The flow of reactant gases was maintained, preferably at a linear velocity of about 2 cm/see.
- the flow of nitrogen and titanium tetrachloride was shut off, and the hydrogen was allowed to flow at 19 slm until the reactor cooled to ambient temperature.
- the system was evacuated to about 30 torr and backfilled with argon before removal of the TiN whiskers.
- the shape and morphology of the whiskers were observed by a scanning electron microscope. The whiskers were found to vary in diameter from 1 to 10 micrometers and were straight to alternating surface morphologies on the faces parallel to the growth axis. Typical results are shown in Table 4.
- the metal halide reactant gases may include halides of titanium, zirconium, hafnium, niobium, tantalum, or tungsten and be mixed with a hydrocarbon gas to produce carbide whiskers.
- a mixture of metal halides may be used to produce whiskers comprising a solid solution of metal carbides, nitrides, or carbonitrides.
- Nitrogen gas and/or ammonia may be substituted for or mixed with the hydrocarbon gas to produce nitride or carbonitride whiskers of titanium, zirconium, hafnium, niobium or tantalum.
- the whiskers produced according to the present invention were subjected to a post-growth treatment prior to removal of the whiskers from the reactor to remove residual nickel catalyst used to grow the whiskers.
- the process was a two-step procedure. First, the whiskers were treated at between 350 to 400 degrees C at one atmosphere pressure with 2.8 slm of HCl in 11.4 slm of argon gas for approximately one hour to convert the elemental nickel residual catalyst to NiCl 2 . Second, the whiskers were then heated to 1000 degrees C and treated with 11.4 slm of argon for one hour to cause the NiCl 2 to sublime. The nickel content of the treated whiskers was reduced from 1-2 wt% to 0.2 wt%, an order of magnitude reduction.
- the present invention provides an improved CVD process for producing high purity, single crystal metal carbide, nitride, or carbonitride whiskers useful for composite applications.
- whiskers produced according to the present invention and incorporated in composite materials are expected to provide composite materials having increased fracture toughness, hardness, and wear resistance for such applications as cutting tools, wear parts, dies, turbines, nozzles and the like.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
L'invention se rapporte à un procédé de dépôt en phase vapeur par voie chimique, destiné à produire des barbes à monocristaux de carbures, nitrures ou carbonitrures métalliques. Le procédé consiste à soumettre à un écoulement de rinçage une chambre de réaction présentant une surface de substrat de croissance appropriée, qui est chauffée à une température comprise entre 1120 et 1225°C, et à faire couler les gaz réactifs sur le substrat de croissance, pour entraîner la formation de barbes. Les gaz réactifs sont constitués par un gaz d'halogénure métallique et par un ou plusieurs gaz d'azote et de méthane. Le rapport atomique du carbone et de l'azote au métal est compris entre environ 0,7/1 et 20/1, respectivement. Le rapport volumique de l'hydrocarbure et de l'azote à l'hydrogène est compris entre environ 1/37 et 1/1,6, respectivement. Les matériaux préférés du substrat de croissance sont constitués par de la poudre de nickel dispersée sur des plaques d'oxyde d'alumine ou par du nickel déposé par électrolyse sur des plaques d'oxyde d'aluminium recouvertes de TiC ou de TiN. Les barbes peuvent être soumises à un traitement de post-croissance, destiné à retirer le catalyseur de nickel résiduel utilisé pour la croissance des barbes. Ce procédé s'effectue en deux étapes. Dans la première étape, les barbes sont traitées à une température comprise entre 350 et 400°C à une pression atmosphérique égale à 1 avec 2,8 slm de HCl dans 11,4 slm d'argon, pendant approximativement 1 heure de façon à convertir le catalyseur résiduel de nickel en NiCl2. Dans la seconde phase, les barbes sont chauffées à une température de 1000°C et traitées avec 11,4 slm d'argon, pendant 1 heure, de façon à entraîner la sublimation du NiCl2. Il en résulte une réduction de la teneur en nickel résiduel des barbes de 1-2 % en poids à 0,2% en poids, soit d'un ordre de grandeur, cette réduction n'affectant pas négativement les propriétés physiques des barbes.The invention relates to a chemical vapor deposition process for producing single crystal barbs of metal carbides, nitrides or carbonitrides. The method consists in subjecting to a rinsing flow a reaction chamber having an appropriate growth substrate surface, which is heated to a temperature between 1120 and 1225 ° C, and in causing the reactive gases to flow on the growth substrate, to cause the formation of beards. The reactive gases consist of a metal halide gas and one or more nitrogen and methane gases. The atomic ratio of carbon and nitrogen to metal is between about 0.7 / 1 and 20/1, respectively. The volume ratio of hydrocarbon and nitrogen to hydrogen is between about 1/37 and 1 / 1.6, respectively. The preferred materials of the growth substrate consist of nickel powder dispersed on alumina oxide plates or by nickel deposited by electrolysis on aluminum oxide plates coated with TiC or TiN. The barbs can be subjected to a post-growth treatment, intended to remove the residual nickel catalyst used for the growth of the barbs. This process is carried out in two stages. In the first step, the barbs are treated at a temperature between 350 and 400 ° C at an atmospheric pressure equal to 1 with 2.8 slm of HCl in 11.4 slm of argon, for approximately 1 hour so as to convert the residual nickel to NiCl2 catalyst. In the second phase, the barbs are heated to a temperature of 1000 ° C. and treated with 11.4 slm of argon, for 1 hour, so as to cause the sublimation of NiCl2. This results in a reduction in the residual nickel content of the barbs from 1-2% by weight to 0.2% by weight, ie of an order of magnitude, this reduction not negatively affecting the physical properties of the barbs.
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US35464189A | 1989-05-19 | 1989-05-19 | |
US354641 | 1989-05-19 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0472666A1 true EP0472666A1 (en) | 1992-03-04 |
EP0472666A4 EP0472666A4 (en) | 1995-03-29 |
Family
ID=23394290
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP90911429A Withdrawn EP0472666A4 (en) | 1989-05-19 | 1990-03-29 | Cvd grown transition metal carbide and nitride whiskers |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0472666A4 (en) |
JP (1) | JPH04507394A (en) |
KR (1) | KR920701535A (en) |
CA (1) | CA2015609A1 (en) |
WO (1) | WO1990014451A1 (en) |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3202987B2 (en) * | 1990-11-26 | 2001-08-27 | 東海カーボン株式会社 | Manufacturing method of titanium carbide whisker |
US5160574A (en) * | 1991-05-30 | 1992-11-03 | Aluminum Company Of America | Process for production of small diameter titanium carbide whiskers |
JP3769739B2 (en) * | 1994-11-17 | 2006-04-26 | 住友電気工業株式会社 | Porous ceramic film and manufacturing method thereof |
SE9900213D0 (en) * | 1999-01-26 | 1999-01-26 | Sandvik Ab | Manufacture of transition metal carbide and carbonitride whiskers with low residual oxygen and intermediate oxide phases |
FR2848204B1 (en) * | 2002-12-09 | 2007-01-26 | Commissariat Energie Atomique | METHODS OF SYNTHESIS AND GROWTH OF NANOTIGES OF A METALLIC CARBIDE ON A SUBSTRATE, SUBSTRATES THUS OBTAINED AND THEIR APPLICATIONS |
EP2599749A1 (en) | 2011-11-30 | 2013-06-05 | Neoker, S.L | Method for the purification of alpha-alumina fibers |
CN105140495A (en) * | 2015-07-15 | 2015-12-09 | 田东 | Method for preparing tin-based anode material by vapor deposition |
CN114988388B (en) * | 2022-06-08 | 2023-09-15 | 电子科技大学 | Acoustic suspension CVD (chemical vapor deposition) carbon material preparation integrated device for electric spark synthesis catalyst |
Citations (1)
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US4900525A (en) * | 1986-08-25 | 1990-02-13 | Gte Laboratories Incorporated | Chemical vapor deposition reactor for producing metal carbide or nitride whiskers |
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US3253886A (en) * | 1961-05-09 | 1966-05-31 | Union Carbide Corp | Process for producing ultrafine powders of refractory materials |
DE1545792B2 (en) * | 1965-02-27 | 1975-08-07 | Bayer Ag, 5090 Leverkusen | Process for the preparation of 4-Hydroxyplperidinen |
US3840647A (en) * | 1969-01-24 | 1974-10-08 | Suwa Seikosha Kk | Method for producing whiskers |
US3761576A (en) * | 1970-08-24 | 1973-09-25 | Ppg Industries Inc | Preparation of titanium carbide |
US3786133A (en) * | 1970-09-11 | 1974-01-15 | Quebec Iron & Titanium Corp | Titanium carbide preparation |
DE2355890A1 (en) * | 1972-11-08 | 1974-07-11 | Nat Res Dev | NUCLEAR RESONANCE SPECTROMETER AND DEVICE FOR OPERATING SUCH SPECTROMETER |
US4491636A (en) * | 1982-05-05 | 1985-01-01 | Exxon Research & Engineering Co. | Process using halogen/oxygen for reactivating iridium and selenium containing catalysts |
JPS60141689A (en) * | 1983-12-27 | 1985-07-26 | イビデン株式会社 | Silicon carbide sliding member and manufacture |
JPS60175537A (en) * | 1984-02-22 | 1985-09-09 | Toyota Motor Corp | Preparation of ultra-fine ceramic particles |
JPS61275200A (en) * | 1985-05-28 | 1986-12-05 | Tokai Carbon Co Ltd | Method for purifiying sic whisker |
US4606902A (en) * | 1985-10-03 | 1986-08-19 | The United States Of America As Represented By The Secretary Of Commerce | Process for preparing refractory borides and carbides |
US4812301A (en) * | 1986-04-24 | 1989-03-14 | The United States Of America As Represented By The Secretary Of The Interior | Production of titanium nitride, carbide, and carbonitride powders |
US4756791A (en) * | 1986-08-25 | 1988-07-12 | Gte Laboratories Incorporated | Chemical vapor deposition process for producing metal carbide or nitride whiskers |
JPH0818919B2 (en) * | 1987-04-03 | 1996-02-28 | 東芝タンガロイ株式会社 | Whisker manufacturing method with excellent yield |
US4858084A (en) * | 1988-07-01 | 1989-08-15 | Richard Sheryll | Illuminated coaster for a drinking vessel |
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1990
- 1990-03-29 EP EP90911429A patent/EP0472666A4/en not_active Withdrawn
- 1990-03-29 KR KR1019910701629A patent/KR920701535A/en not_active IP Right Cessation
- 1990-03-29 JP JP2510961A patent/JPH04507394A/en active Pending
- 1990-03-29 WO PCT/US1990/001755 patent/WO1990014451A1/en not_active Application Discontinuation
- 1990-04-27 CA CA002015609A patent/CA2015609A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4900525A (en) * | 1986-08-25 | 1990-02-13 | Gte Laboratories Incorporated | Chemical vapor deposition reactor for producing metal carbide or nitride whiskers |
Non-Patent Citations (2)
Title |
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PATENT ABSTRACTS OF JAPAN vol. 11, no. 136 (C-419) (2583) 30 April 1987 & JP-A-61 275 200 (TOKAI CARBON CO LTD) 5 December 1986 * |
See also references of WO9014451A1 * |
Also Published As
Publication number | Publication date |
---|---|
JPH04507394A (en) | 1992-12-24 |
EP0472666A4 (en) | 1995-03-29 |
WO1990014451A1 (en) | 1990-11-29 |
CA2015609A1 (en) | 1990-11-19 |
KR920701535A (en) | 1992-08-12 |
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