GB435754A - Improvements in or relating to the production of carbides, carbonitrides, nitrides, borides, silicides and titanides - Google Patents

Abstract

Carbides, carbonitrides, nitrides, borides, silicides and titanides adapted for the manufacture of tools &c., are obtained from other compounds containing the desired elements by supplying heat to these compounds in their gaseous and vaporous state within the free space of a chamber by heating the latter solely from the exterior thereof to a temperature between 800--2500 DEG C. the desired compounds being precipitated out of the space in the solid form. According to a modification at least one but not all of the elements intended for the reaction are supplied in the gaseous or vaporous elemental form instead of as a compound. The elements to be converted in carbides &c. may be supplied as volatile chlorides, fluorides, iodides, oxides or carbonyls, for example, titanium tetrachloride, molybdenum hexachloride, chlorides of zirconium and tungsten, iodides and fluorides of titanium, zirconium, molybdenum, or tungsten, carbonyls of iron, nickel, cobalt, chromium, molybdenum, tungsten, vanadium, platinum, ruthenium, manganese and uranium and oxides of molybdenum and tungsten. Such compounds may be reacted with hydrocarbons such as benzol or blue gas to produce carbides, with elementary nitrogen to produce nitrides, with silicon hydride to product silicides, with boron hydride in the absence of air or oxygen, or with boron fluoride, to produce borides, and with a hydrocarbon and nitrogen to produce carbonitides. Two or more carbides, nitrides or the like may be produced simultaneously in the same reaction chamber by the introduction of a plurality of volatile compounds and/or elements. The volatile compounds or elements may be conveyed to the reaction chamber by means of carrier gases or vapours which preferably consist wholly or partially of gases which are to take part in the reaction. For example the gas mixture from which tungsten nitride is to be obtained may be produced by passing nitrogen through a solution of tungsten carbonyl. If the quantity of volatile liquid so introduced into the gas is excessive diluent gases such as hydrocarbons or nitrogen may be added. The reaction temperature may be so controlled as to cause the formation of mixed crystals between the precipitated products. For example, mixed crystals of tungsten carbide and molybdenum carbide may be produced from the respective metal carbonyls and a hydrocarbon at 1600--2000 DEG C., similarly mixed crystals of molybdenum and titanium carbide may be obtained from their chlorides and a hydrocarbon at 1400--2000 DEG C. According to examples: (1) a mixture of hydrocarbon gas and hydrogen is passed through a benzol solution of tungsten carbonyl and then through a carbon tube heated to 1200--1400 DEG C. to produce tungsten carbide; (2) a current of blue gas is passed through benzol, then through titanium tetra chloride and finally to a heated chamber, e.g. a carbon tube heated to 2000--2500 DEG C. titanium carbide being precipitated; (3) nitrogen is passed through molybdic acid heated to 1400 DEG C. in an alundum crucible, the resulting gases being blown into a reaction chamber at 800--1400 DEG C. containing a hydrocarbon to produce molybdenum carbide. The carbides &c. so obtained may be fused or sintered together or may be embedded in a matrix of a binding agent (e.g. a metal). The carbides &c. may also be allowed to drop directly into the binding agent which is at the bottom of the reaction chamber in the liquid state. Alternatively, the carbides &c. may be obtained from the gas phase simultaneously with the binding agents, both carbide &c. forming compounds and metal forming compounds being introduced into the heated reaction chamber. The binding metals, e.g. cobalt, iron, chromium, manganese or nickel may be introduced into the reaction chamber in the form of carbonyl, oxide or oxalate, if desired with the aid of a carrier gas or vapour. The non-carburization of the binding metals may be assisted by the presence of carbon monoxide. The carbides and binding agents may also be produced separately from the gas phase and then mixed. The resulting powder mixtures may be pressed into the desired form and sintered or fused. The Specification as open to inspection under Sect. 91 comprises also the employment of ammonia in the production of nitrides. This subject-matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specification 12314/11, [Class 1 (ii)].ALSO:Carbides, carbonitrides, nitrides, borides, silicides, and titanides adapted for the manufacture of tools &c., are obtained from other compounds containing the desired elements by supplying heat to these compounds in their gaseous and vaporous state within the free space of a chamber by heating the latter solely from the exterior thereof to a temperature between 800-2500 DEG C., the desired compounds being precipitated out of the space in the solid form. According to a modification at least one but not all of the elements intended for the reaction are supplied in the gaseous or vaporous elemental form instead of as a compound. The carbides &c. of molybdenum, tungsten, titanium, zirconium, iron, nickel, chromium, vanadium, platinum, ruthenium, manganese and uranium may be so obtained. Two or more carbides, nitrides or the like may be produced simultaneously in the same reaction chamber by the introduction of a plurality of volatile compounds and/or elements. The volatile compounds or elements may be conveyed to the reaction chamber by means of carrier gases or vapours which preferably consist wholly or partially of gases which are to take part in the reaction. If the quantity of volatile liquid so introduced into the gas is excessive diluent gases such as hydrocarbons or nitrogen may be added. The reaction temperature may be so controlled as to cause the formation of mixed crystals between the precipitated products. The carbides &c. so obtained may be fused or sintered together or may be embedded in a matrix of a binding agent, (e.g. a metal). The carbides &c. may also be allowed to drop directly into the binding agent which is at the bottom of the reaction chamber in the liquid state. Alternatively, the carbides &c. may be obtained from the gas phase simultaneously with the binding agents, both carbide &c. forming compounds and metal forming compounds being introduced into the heated reaction chamber. The binding metals, e.g. cobalt, iron, chromium. manganese or nickel may be introduced into the reaction chamber in the form of carbonyl, oxide or oxalate, if desired with the aid of a carrier gas or vapour. The non-carburization of the binding metals may be assisted by the presence of carbon monoxide. The carbides and binding agents may also be produced separately from the gas phase and then mixed. The resulting powder mixtures may be pressed into the desired form and sintered or fused. Reference has been directed by the Comptroller to Specification 12314/11, [Class 1 (ii)].ALSO:Carbides, carbonitrides, nitrides, borides, silicides, and titanides adapted for the manufacture of tools &c., are obtained from other compounds containing the desired elements by supplying heat to these compounds in their gaseous and vaporous state within the free space of a chamber by heating the latter solely from the exterior thereof to a temperature between 800-2500 DEG C., the desired compounds being precipitated out of the space in the solid form. According to a modification, at least one but not all of the elements intended for the reaction are supplied in the gaseous or vaporous elemental form instead of as a compound. Two or more carbides, nitrides or the like may be produced simultaneously in the same reaction chamber by the introduction of a plurality of volatile compounds and/or elements. The reaction temperature may be so controlled as to cause the formation of mixed crystals between the precipitated products. For example, mixed crystals of tungsten carbide and molybdenum carbide may be produced from the respective metal carbonyls and a hydrocarbon at 1600-2000 DEG C.; similarly mixed crystals of molybdenum and titanium carbide may be obtained from their chlorides and a hydrocarbon at 1400-2000 DEG C. The carbides &c. so obtained may be fused or sintered together or may be embedded in a matrix of a binding agent (e.g. a metal). The carbides &c. may also be allowed to drop directly into the binding agent which is at the bottom of the reaction chamber in the liquid state. Alternatively, the carbides &c. may be obtained from the gas phase simultaneously with the binding agents, both carbide &c. forming compounds and metal-forming compounds being introduced into the heated reaction chamber. The binding metals, e.g. cobalt, iron, chromium, manganese or nickel, may be introduced into the reaction chamber in the form of carbonyl, oxide, or oxalate, if desired with the air of a carrier gas or vapour. The non-carburization of the binding metals may be assisted by the presence of carbon monoxide. The carbides and binding agents may also be produced separately from the gas phase and then mixed. Reference has been directed by the Comptroller to Specification 12314/11, [Class 1 (ii)].