KR920701535A - Transition Metal Carbide and Nitride Whiskers Grown by Chemical Vapor Deposition (CVD) - Google Patents

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Transition Metal Carbide and Nitride Whiskers Grown by Chemical Vapor Deposition (CVD)

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Claims (28)

a) flushing an enclosed reaction chamber from the surrounding atmosphere with flowing water, wherein the reaction chamber is formed of one or more materials suitable for catalyzing and supporting a substrate for nucleation and growth of whiskers And a growth substrate surface, wherein the growth substrate surface is maintained at a working temperature suitable for growing a whisker, wherein the at least one substrate table is deposited on a portion of the substrate surface. a flushing step of the hot material with t) the metal powder; And b) one or more metal halide gases selected from the group consisting of halides of titanium, zirconium, hafnium, niobium and tantalum and nitrogen, ammonia and aliphatic which are pyrolysable at operating temperatures to form free carbon. A reactant comprising at least one gas selected from a combination of hydrocarbon gases is flowed through the reaction chamber at an atmospheric pressure at an atmosphere of carbon + nitrogen to metal and a volume ratio of hydrocarbon + nitrogen or ammonia to hydrogen sufficient to form a whisker Incorporating the hydrophobic mixture, wherein the flowing mixed gas comprises a mixing step maintained at a suitable linear rate for a time sufficient to nucleate and grow metal carbide, nitride or carbon nitride whiskers on the growth substrate material surface; Metal Carbide, Nitride or Carbon Geography How to make cargo whiskers. The method of claim 1, wherein the metal powder is selected from the group consisting of transition metals and iron alloys. The method of claim 2, wherein the metal powder is selected from the group consisting of alloys containing nickel and at least 50 wt% nickel. The method of claim 2, wherein the particle size of the metal powder is about 2 microns. The method of claim 1 wherein the hot material is selected from the group consisting of aluminum oxide, mullite or graphite. a) one or more growth substrate surfaces formed of one or more materials suitable for catalyzing and supporting a flushing substrate with a hydrophobic flow flowing in a closed reaction chamber from the surrounding atmosphere, wherein the growth substrate surface is operated between about 1120 ° C and 1225 ° C. A flushing step maintained at temperature; And b) at least one metal halide gas selected from the group consisting of halides of titanium, zirconium, hafnium, niobium and tantalum and a combination of nitrogen, ammonia and aliphatic hydrocarbon gas pyrolysable at process temperature to form free carbon. The reactant comprising at least one gas selected is selected at ambient atmosphere at an original ratio of carbon + nitrogen to metal of about 0.1: 1 to 20: 1 and a volume ratio of carbon number + nitrogen or ammonia to hydrogen of from 1:37 to 1: 1.6, Mixing the flowing gas through the reaction chamber, the flowing mixing gas being maintained at a suitable linear speed for a time sufficient to nucleate and grow metal carbide, nitride or carbon nitride whiskers on the growth substrate material surface; A metal carbide, nitride or carbon nitride whisker comprising a mixing step How to manufacture. The method of claim 6, wherein the linear velocity of the flowing gas is maintained at about 2-4 cm / sec. 7. A method according to claim 6, wherein the at least one substrate material is a high temperature material having a metal powder deposited on a portion of the substrate surface. The method of claim 8, wherein the metal powder is selected from the group consisting of transition metals and iron alloys. The method of claim 9, wherein the metal powder is selected from the group consisting of nickel and alloys containing at least 50 wt% nickel. The method of claim 9, wherein the metal powder is about 2 microns. The method of claim 8, wherein the high temperature material is selected from the group consisting of aluminum oxide, mullite, or graphite. a) flushing the closed reaction chamber from the surrounding atmosphere with a flowing water, the reaction chamber comprising at least one growth substrate surface formed of at least one material suitable for catalyzing and supporting a substrate for nucleation and growth of the whiskers Flushing the growth substrate surface at a working temperature of about 1120 ° C. to 1225 ° C .; And b) a reactant comprising at least 0.7 aliphatic hydrocarbons pyrolysable at operating temperature to form free carbon and a metal halide gas selected from the group consisting of halides of titanium, zirconium, hafnium, niobium, tantalum and tungsten. Mixing at a surrounding atmospheric pressure with an aqueous ratio of carbon to metal of 1: 1 and a volume ratio of hydrocarbon to hydrogen of about 1:37 to hydrophobic gas flowing through the reaction chamber, wherein the flowing mixed gas is present on the growth substrate surface. A method of producing a metal carbide comprising the step of mixing at a suitable linear speed for a time sufficient to nucleate and grow a metal carbide whisker. The method of claim 13, wherein the working temperature is about 1190 ° C. to 1220 ° C. 15. The method of claim 13, wherein the linear velocity of the flowing mixing gas is maintained at about 2 cm / sec. The process of claim 13, wherein the hydrocarbon gas is selected from the group consisting of compounds of the formula C _n H _{2n +} , C _n H _2n or C _n H _{2n −} . Where n is an integer from 1 to 4 The method of claim 16, wherein the hydrocarbon gas is selected from the group consisting of methane, propane and acetylene. A method of removing a residual metal catalyst from a metal carbide, nitride or carbon nitride whiskey in an enclosed reaction chamber comprising at least one substrate surface for supporting a whisker, the method comprising: a) metal for a first predetermined time Supplying to the reaction chamber a reactant comprising at least one gas selected from the group consisting of hydrogen, hydrogen halide or glocarbon at a first operating temperature sufficient to form a halide with a catalyst: and b) a metal from the reaction chamber Flushing the reaction chamber to a second small temperature sufficient to evaporate the metal halide for a second predetermined time to remove halide. 19. The method of claim 18, comprising mixing a relatively inert carrier gas with a reactant flowing through the reaction chamber at an enclosed pressure. The method of claim 19, wherein the carrier gas is argon. The method of claim 18, wherein the reactant is hydrogen halide. The method of claim 21, wherein the hydrogen halide is HCI. The method of claim 22, wherein the first operating temperature is less than about 430 ° C. 24. The method of claim 23, wherein the first working temperature is between 350 ° C. and 400 ° C. 25. The method of claim 18, wherein the second operating temperature is at least about 970 ° C. 19. Metal carbide, nitride or carbon nitride whisker prepared according to the method of claim 1. Metal carbide, nitride or carbon nitride whisker prepared according to the method of claim 6. A metal carbide, nitride or carbon nitride whisker produced by chemical vapor deposition (CVD) and treated to remove residual catalyst, having the same physical properties as the untreated whisker. ※ Note: The disclosure is based on the initial application.