CA1156267A - Production of ultra-hard particles - Google Patents
Production of ultra-hard particlesInfo
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- CA1156267A CA1156267A CA000380198A CA380198A CA1156267A CA 1156267 A CA1156267 A CA 1156267A CA 000380198 A CA000380198 A CA 000380198A CA 380198 A CA380198 A CA 380198A CA 1156267 A CA1156267 A CA 1156267A
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Abstract
Abstract Production of Ultra-Hard Particles The production of an ultra-hard particle composed substantially of carbon as the dominant element is taught. The ultra-hard particle is the product of the reaction of a metal carbide selected from the group consisting of A14C3 and Be2C with a member selected from the group consisting of CHnXAY(4-n)-A ' C2Hn'XA'Y(6-n')-A'' C2Hn"XA"Y(4-n")-A" and X2 wherein X
and Y are different halogens selected from the group consisting of chlorine, bromine, iodine and fluorine, and wherein A is an integer from O to 4, A' is an integer from O to 6 and A" is an integer from O to 4, and wherein n is an-integer from O to 4, n' is an integer from O to 6 and n" is an integer from O
to 4, wherein A, A', A", n, n' or n" is the same integer in any particular member selected and wherein n + A = 4, n' + A' + 6 and n" + A" = 4.
and Y are different halogens selected from the group consisting of chlorine, bromine, iodine and fluorine, and wherein A is an integer from O to 4, A' is an integer from O to 6 and A" is an integer from O to 4, and wherein n is an-integer from O to 4, n' is an integer from O to 6 and n" is an integer from O
to 4, wherein A, A', A", n, n' or n" is the same integer in any particular member selected and wherein n + A = 4, n' + A' + 6 and n" + A" = 4.
Description
1 15~267 , Description Production of Ultra~Hard Particles . _ Technical Field This invention relates to the production of ultra-hard particles composed substantially of carbon as the dominant element.
Background Art Numerous attempts were made prior to 1955 to convert various forms of carbon, including graphite, into its diamond form or other ultra-hard carbonaceous forms. None of these attempts have been adequately substantiated. A valid diamond synthesis was reported in 1955 but details were not revealed until 1959 (Nature 184:1094-8, 1959). At temperatures of 1200 to 2400C and pressures ranging from 55,000 to 100,000 atmospheres or more, carbon is converted into its diamond ~orm in the presence of transition metals (chromium, manganese, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum) or tantalum. Higher pressures are required at higher temperatures.
Rather esoteric means were also investigated in the quest for a more convenient graphite to diamond conversion. As reported in Phys. Rev. Letters 7:367 (1961), it was taught that diamond might be obtained in less than a microsecond by the action of extremely high pressure explosive shock waves on graphite. In fact, diamonds were actually recovered from carbon subjected to an explosive shock.
Epitaxial methods have also been reported where the decomposition of gases, such as methane, ethane and propane in contact with diamond powder was found to promote diamond growth. However, in performing epi-taxial techniques, temperatures in the vicinity of 1300K. and pressures on the order of 10 3 to 10 4 atmospheres were found to be required.
It is obvious that the prior techniques employed in the fabrication of synthetic diamonds and other ultra-hard carbonaceous materials are at best cumber-some and expensive to carry out. The maintenance of any extremes in temperature and pressure requires enormous energy and sophisticated equipment, which in turn detracts from the widespread commercialization of synthetic diamond fabrication.
Disclosure of Invention It is an object of the present invention to produce ultra-hard carbonaceous particles while elimi-nating the drawbacks experienced in prior art produc-tion techniques.
It is a further object of the present invention to produce ultra-hard carbonaceous particles without the necessity for employing extreme temperatures and pressures which are required by the prior art.
It is yet a further object of the present inven-tion to produce ultra-hard carbonaceous particles from sources other than graphite or amorphous carbon.
It is yet a further object of the present inven-tion to produce ultra-hard carbonaceous particles by means of high thermodynamic drive carbon yielding reactions.
It has been found that ultra-hard carbonaceous particles can be produced from the reaction of a metal carbide such as aluminum carbide (Al4C3) or beryllium carbide (Be2C) when reacted with halogens and related halocompounds. Care has been exercised to minimize or eliminate the presence of substances which would rèact 1 15~267 parasitically with carbon or the reactants, such as oxygen and oxygenated compounds with oxidizing power.
The reactions have tended to produce very hard and strong, covalently bonded lattice structures under highly exothermic conditions at moderate temperatures.
The reactions have been accomplished at relatively low temperatures (a few hundred degrees C) and at low pressures (a few atmospheres or less). It has also been an objective to employ a system having no solvency capability for carbon while carrying out the reactions of the present invention at favorable (spontaneous) energies on the order of 100 times as great or greater, per gram atom~ as the diamond-graphite interconversion energy. Under proper conditions, the metal carbides are quite reactive having carbon atoms that are indi-vidually isolated. In actual reactions which have been carried out, the reaction energy has been found to be enormously favorable and more than 100 times as great per carbon atom as the graphite-carbon inter-conversion energy.
Best Mode for Carr in Out the Invention It has been found that the aluminum carbide or theberyllium carbide used in the invention must be rela-tively free of impurities, particularly carbon. If free carbon is present in the metal carbide, graphite nucleation may occur and this greatly diminishes the yield of ultra-hard carbon particles. For this reason, aluminum carbide or beryllium carbide starting materials are selected which possess slightly greater stoichiometric aluminum or beryllium to carbon ratios than are indicated by the formulae Al4C3 or Be2C. The physical forms of the aluminum carbide or beryllium carbide are not absolutely critical in carrying out the present invention. However, the various reactions 1 15~267 occur more rapidly with finely divided particles in the 50-500 mesh range.
The reaction is carried out in a hot melt system.
The melt system is comprised of a molten solution of more than one metal halide wherein the metals are selected from the group consisting of Groups I, II and III of the periodic table and the halides are selected from the group consisting of chlorine, bromine, iodine and fluorine. The presence of oxidizing anions such as sulfates, nitrates and carbonates and hydrogen contain-ing anions such as hydroxides should be avoided in the melt system.
The melt system performs several valuable func-tions in carrying out the present invention. Firstly, it provides for a reaction medium at a temperature substantially below temperatures at which diamond to graphite reversion occurs at a measurable rate.
Secondly, it acts as a heat sink. For example, a melt system comprised of lithium chloride (LiCl) combined with aluminum chloride (AlCl3) is fluid at a temperature as low as 150C. Ideally, the melt system can be composed of an aluminum halide (AlX3, where X
represents Cl, Br or I although some F may also be present), complexed with one or more metallic halides such as alkaline halides and alkaline earth halides.
When lithium chloride is used with aluminum chloride at a molar ratio LiCl:AlCl3 greater than one, the predomi-nant melt species are Li+, AlCl4 , and Cl . If the ratio is high, a solid LiCl phase or Li3~lCl6 may be present. If the molar ratio of LiCl:AlCl3 is less than 1:1, including as high as approximately 1:2, the pre-dominant melt species are Li+, AlCl4 , and Al2Cl7 .
Br may be substituted wholly or partially for Cl. Some fluorine, iodide or iodine may be present in free form or in the aluminum-containing anions in either the 1 15~267 initial melt or the final melt system. Such a melt system also exhibits substantial solvent and penetrant capability for Al2O3 and hydroxy aluminous complexes which naturally form on the surface of aluminum or aluminum carbide in the presence of oxygen or water. A
coating of Al2O3, or bound aluminum atoms bearing OH groups, is extremely tenacious and provides a substantial barrier to the carrying out of the present invention. Thus, the melt system, to function in the present invention, must have solvency capability for aluminum oxide, aluminum oxygen complexes and hydrogen-containing aluminum oxygen complexes. The melt system must also have the ability to wet the metal carbide surface and must have the ability not to destroy the carbon halide reactants or the metal carbide. It must also be substantially anhydrous and substantially free of hydroxyl groups.
The present invention can be carried out at pressures between approximately 0.1 to 100 atmospheres.
As an upper limit, the reaction should take place at a pressure less than the pressure where diamond would be the stable form of carbon if the reaction was allowed to reach equilibrium, approximately 20,000 atmospheres.
However, above 100 atmospheres, there is little benefit to the reaction while rather sophisticated equipment is necessary to maintain such high pressures. The optimum temperature range would depend upon the actual compounds used to make up the melt and as primary reactants. As a general rule, temperatures between approximately 100 to 700C are to be used in carrying out the reaction noting that the temperature must be high enough to at least maintain the melt system in a liquid state.
The following examples demonstrate a number of specific embodiments of the invention.
Example 1 The melt system is formed by the preparation of a solution of mixed halides which are heated for a suf-ficient time to insure that substantially all hydrogen and hydrogen chloride have been purged from the system.
In this example, 24.5 g of anhydrous LiCl was heated in a 500 ml flask at approximately 130-140C for two days.
Approximately 67 g of anhydrous AlC13 was then added under an argon blanket, the temperature elevated to approximately 250C and the mixture stirred for 35 minutes at which time very little HCl was evident.
After the melt system was formed, the metal carbide was added. In this example, 2.9 9 of Al4C3 as added and held briefly. The halogen-containing reactant can then be added to the solution by stepwise additions until an excess is present. In this example, 1 ml portions of CCl4 were added every ten minutes to a total of 10 mls followed by further 2 ml additions at ten minute intervals. The temperature was main-tained at approximately 265C throughout the CCL4 additions and the suspension allowed to cool slightly thereafter.
The melt suspension which was formed according to the following reaction:
A14C3 + 3CC14 >6C + 4AlCl3 was washed by incorporating the suspension in 10 mls of concentrated HCl and 200 mls H2O. The suspension was boiled for 50 minutes. Alt~rnatively, this suspension could have been incorporated in ~queous solutions of non-oxidizing acids such as H2SO4 or CH3SO3H or even nonaqueous systems such as nitrobenzene. The suspension was then filtered and the solids washed in 100 mls of 1:10 HCl followed by three 100 ml water additions, two 40 ml isopropyl alcohol washes, and concluding by four 25 ml acetone washes. The product was dried, resulting in ultra-hard carbonaceous particles.
1 15¢267 Example 2 To the same melt system as developed in Example 1 was added, in addition to the aluminum carbide, approx-imately 2 g of XBr. CC14 remained as the halogen reactant and was added in a stepwise fashion much as was done in Example 1. The final ultra-hard carbon-aceous product was washed and dried, again, as was done in Example 1.
Example 3 The melt system was the same as Example 1 while the reactants included aluminum carbide and CBr4. More specifically, after the A14C3 was added to the hot melt, 1 g of CBr4 was added followed by 10 mls of CC14 in 0.5 ml portions every five minutes. The ultra-hard carbonaceous product was washed as done in Example 1.
Example 4 The melt system was prepared as in Example 1 and aluminum carbide was chosen as a first reactant. The remaining reactants included 1 g of CBr4 and a total of 13.6 g of C2C16 added in 1.7 g portions every five minutes. The ultra-hard carbonaceous particles were washed and dried as in Example 1 producing the final product according to the following reaction:
2C2C16 ~ A14C3 ~4A~C13 + 7C.
Example 5 To the melt system prepared as in Example 1 was added 2.9 g of A14C3 and 2 mg of FeS in 18 mg of NaCl as a nucleating agent. These latter ingredients were mixed in the melt system for approximately ten minutes followed by the addition of 1 g of CBr4 and 7 g of C2C16 while allowing the fluid reaction mixture to reflux for approximately 65 minutes at 240C. Three more additions of C2C16 were made over the next 10 minutes and the suspension was refluxed again for 20 minutes. A final 3 g of C2Cl6 was added over a 20 minute interval and the suspension again heated for 30 minutes. The ultra-hard carbonaceous particles were then washed and dried as in Example 1.
Example 6 The melt system was prepared as in Example 1 to which was added 2.9 g of Al4C3 and 20 mg of ten percent FeS in NaCl as a nucleating agent. The fluid reaction mixture was stirred at approximately 240C for 15 minutes after which a total of 24 g of CBr4 was added in 2 g portions every 5 minutes. The reaction proceeded according to the following equation:
Al C + 3CBr ~ 4AlBr3 + 6C
and the ultra-hard carbonaceous particles were filtered, washed and dried according to the manner employed in Example 1.
Example 7 The melt system was formed by mixing 10 g of powdered KBr, 21 g of LiCl and approximately 67 g of AlCl3. The mixture was heated to approximately 240C
and stirred for 1 hour under argon. To the melt system was added 20 mg of HgCl2 as a possible catalyst to 25 which 2.9 g of A14C3 was added. After waiting 5 minutes, approximately 1 ml of C2Cl4 was added to the hot melt. The solution was allowed to reflux and, after 10 minutes, 1 g of CBr4 was added. Then, at 10 minute intervals, 1 ml portions of C2Cl4 were added until a total of 9 ml were in the system. The reactants were heated for 45 minutes, filtered, washed and dried as in Example 1. The reaction proceeded according to the following equation: -g Al4C3 + 3C2cl4 ~ 4AlCl3 + 9C
forming ultra-hard carbonaceou's particles.
Example 8 The melt system of Example 1 was prepared and to it was added 2.9 g of Al4C3 and 20 mg of ten percent FeS in NaCl as a nucleating agent. The second reactant was made up of 8 ml Br2 which was added in 0.4 ml portions at 5 minute intervals. The reaction products were filtered, washed and dried as in Example 1 produc-ing a product according to the following equation:
Al C + 6Br - - > 4AlBr3 + 3C.
Example 9 A melt system was prepared according to Example 1 with the addition of 5 g of KI. To this was added approximately 2.88 g of Al4C3 at 250C which was reacted with CCl4 added to the system every five minutes in 0.5 ml amounts totaling 20 additions. The reaction produced ultra-hard particles which were filtered, washed and dried according to the procedure of Example 1.
Example 10 A,melt system was prepared according to Example 1 with the addition of 5 g of NaF. To the melt systém was added approximately 2.88 g of finely ground Al4C3 to which was added CCl4 in 1 ml amounts every ten minutes totaling 12 additions. The reaction product was filtered, washed and dried according to.Example 1 producing the ultra-hard carbonaceous materials of this invention.
1 15~7 --1 o--Example 11 A melt system comprised of 42 g of LiCl and 134 g of AlCl3 was prepared as per Example 1 to which 5.76 g of Al4C3 having a -270 mesh size was added. At a starting temperature of approximately 236C, Freon 11 ~CCl3F) was added in 1 ml amounts every five minutes totaling 23 additions. The reaction product was fil-tered, washed and drièd according to Example 1 produc-ing the ultra-hard carbonaceous materials of the present invention.
Example 12 The melt system of Example 1 was prepared to which approximately 2.88 g of A14C3 was added having a -270 mesh at 242C. Chlorine gas was then bubbled into the hot melt system at a rate of 0.05 cubic feet per hour for 1/2 hour. The rate was then increased to 0.1 cubic feet per hour for the next 2-1/2 hours amounting to a total chlorine addition of 10.7 liters. The reac-tion product was filtered, washed and dried as was shown in Example 1 producing ultra-hard carbonaceous particles according to the present invention.
Example 13 A new melt system was prepared by placing 29.2 g of NaC1 in a flask which was heated to 180~C under vacuum for 2 hours and which was allowed to stand overnight under full vacuum. With mechanical stirring under an argon blanket, 67 g of AlCl3 was added to complete the melt system. To this melt was added
Background Art Numerous attempts were made prior to 1955 to convert various forms of carbon, including graphite, into its diamond form or other ultra-hard carbonaceous forms. None of these attempts have been adequately substantiated. A valid diamond synthesis was reported in 1955 but details were not revealed until 1959 (Nature 184:1094-8, 1959). At temperatures of 1200 to 2400C and pressures ranging from 55,000 to 100,000 atmospheres or more, carbon is converted into its diamond ~orm in the presence of transition metals (chromium, manganese, iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum) or tantalum. Higher pressures are required at higher temperatures.
Rather esoteric means were also investigated in the quest for a more convenient graphite to diamond conversion. As reported in Phys. Rev. Letters 7:367 (1961), it was taught that diamond might be obtained in less than a microsecond by the action of extremely high pressure explosive shock waves on graphite. In fact, diamonds were actually recovered from carbon subjected to an explosive shock.
Epitaxial methods have also been reported where the decomposition of gases, such as methane, ethane and propane in contact with diamond powder was found to promote diamond growth. However, in performing epi-taxial techniques, temperatures in the vicinity of 1300K. and pressures on the order of 10 3 to 10 4 atmospheres were found to be required.
It is obvious that the prior techniques employed in the fabrication of synthetic diamonds and other ultra-hard carbonaceous materials are at best cumber-some and expensive to carry out. The maintenance of any extremes in temperature and pressure requires enormous energy and sophisticated equipment, which in turn detracts from the widespread commercialization of synthetic diamond fabrication.
Disclosure of Invention It is an object of the present invention to produce ultra-hard carbonaceous particles while elimi-nating the drawbacks experienced in prior art produc-tion techniques.
It is a further object of the present invention to produce ultra-hard carbonaceous particles without the necessity for employing extreme temperatures and pressures which are required by the prior art.
It is yet a further object of the present inven-tion to produce ultra-hard carbonaceous particles from sources other than graphite or amorphous carbon.
It is yet a further object of the present inven-tion to produce ultra-hard carbonaceous particles by means of high thermodynamic drive carbon yielding reactions.
It has been found that ultra-hard carbonaceous particles can be produced from the reaction of a metal carbide such as aluminum carbide (Al4C3) or beryllium carbide (Be2C) when reacted with halogens and related halocompounds. Care has been exercised to minimize or eliminate the presence of substances which would rèact 1 15~267 parasitically with carbon or the reactants, such as oxygen and oxygenated compounds with oxidizing power.
The reactions have tended to produce very hard and strong, covalently bonded lattice structures under highly exothermic conditions at moderate temperatures.
The reactions have been accomplished at relatively low temperatures (a few hundred degrees C) and at low pressures (a few atmospheres or less). It has also been an objective to employ a system having no solvency capability for carbon while carrying out the reactions of the present invention at favorable (spontaneous) energies on the order of 100 times as great or greater, per gram atom~ as the diamond-graphite interconversion energy. Under proper conditions, the metal carbides are quite reactive having carbon atoms that are indi-vidually isolated. In actual reactions which have been carried out, the reaction energy has been found to be enormously favorable and more than 100 times as great per carbon atom as the graphite-carbon inter-conversion energy.
Best Mode for Carr in Out the Invention It has been found that the aluminum carbide or theberyllium carbide used in the invention must be rela-tively free of impurities, particularly carbon. If free carbon is present in the metal carbide, graphite nucleation may occur and this greatly diminishes the yield of ultra-hard carbon particles. For this reason, aluminum carbide or beryllium carbide starting materials are selected which possess slightly greater stoichiometric aluminum or beryllium to carbon ratios than are indicated by the formulae Al4C3 or Be2C. The physical forms of the aluminum carbide or beryllium carbide are not absolutely critical in carrying out the present invention. However, the various reactions 1 15~267 occur more rapidly with finely divided particles in the 50-500 mesh range.
The reaction is carried out in a hot melt system.
The melt system is comprised of a molten solution of more than one metal halide wherein the metals are selected from the group consisting of Groups I, II and III of the periodic table and the halides are selected from the group consisting of chlorine, bromine, iodine and fluorine. The presence of oxidizing anions such as sulfates, nitrates and carbonates and hydrogen contain-ing anions such as hydroxides should be avoided in the melt system.
The melt system performs several valuable func-tions in carrying out the present invention. Firstly, it provides for a reaction medium at a temperature substantially below temperatures at which diamond to graphite reversion occurs at a measurable rate.
Secondly, it acts as a heat sink. For example, a melt system comprised of lithium chloride (LiCl) combined with aluminum chloride (AlCl3) is fluid at a temperature as low as 150C. Ideally, the melt system can be composed of an aluminum halide (AlX3, where X
represents Cl, Br or I although some F may also be present), complexed with one or more metallic halides such as alkaline halides and alkaline earth halides.
When lithium chloride is used with aluminum chloride at a molar ratio LiCl:AlCl3 greater than one, the predomi-nant melt species are Li+, AlCl4 , and Cl . If the ratio is high, a solid LiCl phase or Li3~lCl6 may be present. If the molar ratio of LiCl:AlCl3 is less than 1:1, including as high as approximately 1:2, the pre-dominant melt species are Li+, AlCl4 , and Al2Cl7 .
Br may be substituted wholly or partially for Cl. Some fluorine, iodide or iodine may be present in free form or in the aluminum-containing anions in either the 1 15~267 initial melt or the final melt system. Such a melt system also exhibits substantial solvent and penetrant capability for Al2O3 and hydroxy aluminous complexes which naturally form on the surface of aluminum or aluminum carbide in the presence of oxygen or water. A
coating of Al2O3, or bound aluminum atoms bearing OH groups, is extremely tenacious and provides a substantial barrier to the carrying out of the present invention. Thus, the melt system, to function in the present invention, must have solvency capability for aluminum oxide, aluminum oxygen complexes and hydrogen-containing aluminum oxygen complexes. The melt system must also have the ability to wet the metal carbide surface and must have the ability not to destroy the carbon halide reactants or the metal carbide. It must also be substantially anhydrous and substantially free of hydroxyl groups.
The present invention can be carried out at pressures between approximately 0.1 to 100 atmospheres.
As an upper limit, the reaction should take place at a pressure less than the pressure where diamond would be the stable form of carbon if the reaction was allowed to reach equilibrium, approximately 20,000 atmospheres.
However, above 100 atmospheres, there is little benefit to the reaction while rather sophisticated equipment is necessary to maintain such high pressures. The optimum temperature range would depend upon the actual compounds used to make up the melt and as primary reactants. As a general rule, temperatures between approximately 100 to 700C are to be used in carrying out the reaction noting that the temperature must be high enough to at least maintain the melt system in a liquid state.
The following examples demonstrate a number of specific embodiments of the invention.
Example 1 The melt system is formed by the preparation of a solution of mixed halides which are heated for a suf-ficient time to insure that substantially all hydrogen and hydrogen chloride have been purged from the system.
In this example, 24.5 g of anhydrous LiCl was heated in a 500 ml flask at approximately 130-140C for two days.
Approximately 67 g of anhydrous AlC13 was then added under an argon blanket, the temperature elevated to approximately 250C and the mixture stirred for 35 minutes at which time very little HCl was evident.
After the melt system was formed, the metal carbide was added. In this example, 2.9 9 of Al4C3 as added and held briefly. The halogen-containing reactant can then be added to the solution by stepwise additions until an excess is present. In this example, 1 ml portions of CCl4 were added every ten minutes to a total of 10 mls followed by further 2 ml additions at ten minute intervals. The temperature was main-tained at approximately 265C throughout the CCL4 additions and the suspension allowed to cool slightly thereafter.
The melt suspension which was formed according to the following reaction:
A14C3 + 3CC14 >6C + 4AlCl3 was washed by incorporating the suspension in 10 mls of concentrated HCl and 200 mls H2O. The suspension was boiled for 50 minutes. Alt~rnatively, this suspension could have been incorporated in ~queous solutions of non-oxidizing acids such as H2SO4 or CH3SO3H or even nonaqueous systems such as nitrobenzene. The suspension was then filtered and the solids washed in 100 mls of 1:10 HCl followed by three 100 ml water additions, two 40 ml isopropyl alcohol washes, and concluding by four 25 ml acetone washes. The product was dried, resulting in ultra-hard carbonaceous particles.
1 15¢267 Example 2 To the same melt system as developed in Example 1 was added, in addition to the aluminum carbide, approx-imately 2 g of XBr. CC14 remained as the halogen reactant and was added in a stepwise fashion much as was done in Example 1. The final ultra-hard carbon-aceous product was washed and dried, again, as was done in Example 1.
Example 3 The melt system was the same as Example 1 while the reactants included aluminum carbide and CBr4. More specifically, after the A14C3 was added to the hot melt, 1 g of CBr4 was added followed by 10 mls of CC14 in 0.5 ml portions every five minutes. The ultra-hard carbonaceous product was washed as done in Example 1.
Example 4 The melt system was prepared as in Example 1 and aluminum carbide was chosen as a first reactant. The remaining reactants included 1 g of CBr4 and a total of 13.6 g of C2C16 added in 1.7 g portions every five minutes. The ultra-hard carbonaceous particles were washed and dried as in Example 1 producing the final product according to the following reaction:
2C2C16 ~ A14C3 ~4A~C13 + 7C.
Example 5 To the melt system prepared as in Example 1 was added 2.9 g of A14C3 and 2 mg of FeS in 18 mg of NaCl as a nucleating agent. These latter ingredients were mixed in the melt system for approximately ten minutes followed by the addition of 1 g of CBr4 and 7 g of C2C16 while allowing the fluid reaction mixture to reflux for approximately 65 minutes at 240C. Three more additions of C2C16 were made over the next 10 minutes and the suspension was refluxed again for 20 minutes. A final 3 g of C2Cl6 was added over a 20 minute interval and the suspension again heated for 30 minutes. The ultra-hard carbonaceous particles were then washed and dried as in Example 1.
Example 6 The melt system was prepared as in Example 1 to which was added 2.9 g of Al4C3 and 20 mg of ten percent FeS in NaCl as a nucleating agent. The fluid reaction mixture was stirred at approximately 240C for 15 minutes after which a total of 24 g of CBr4 was added in 2 g portions every 5 minutes. The reaction proceeded according to the following equation:
Al C + 3CBr ~ 4AlBr3 + 6C
and the ultra-hard carbonaceous particles were filtered, washed and dried according to the manner employed in Example 1.
Example 7 The melt system was formed by mixing 10 g of powdered KBr, 21 g of LiCl and approximately 67 g of AlCl3. The mixture was heated to approximately 240C
and stirred for 1 hour under argon. To the melt system was added 20 mg of HgCl2 as a possible catalyst to 25 which 2.9 g of A14C3 was added. After waiting 5 minutes, approximately 1 ml of C2Cl4 was added to the hot melt. The solution was allowed to reflux and, after 10 minutes, 1 g of CBr4 was added. Then, at 10 minute intervals, 1 ml portions of C2Cl4 were added until a total of 9 ml were in the system. The reactants were heated for 45 minutes, filtered, washed and dried as in Example 1. The reaction proceeded according to the following equation: -g Al4C3 + 3C2cl4 ~ 4AlCl3 + 9C
forming ultra-hard carbonaceou's particles.
Example 8 The melt system of Example 1 was prepared and to it was added 2.9 g of Al4C3 and 20 mg of ten percent FeS in NaCl as a nucleating agent. The second reactant was made up of 8 ml Br2 which was added in 0.4 ml portions at 5 minute intervals. The reaction products were filtered, washed and dried as in Example 1 produc-ing a product according to the following equation:
Al C + 6Br - - > 4AlBr3 + 3C.
Example 9 A melt system was prepared according to Example 1 with the addition of 5 g of KI. To this was added approximately 2.88 g of Al4C3 at 250C which was reacted with CCl4 added to the system every five minutes in 0.5 ml amounts totaling 20 additions. The reaction produced ultra-hard particles which were filtered, washed and dried according to the procedure of Example 1.
Example 10 A,melt system was prepared according to Example 1 with the addition of 5 g of NaF. To the melt systém was added approximately 2.88 g of finely ground Al4C3 to which was added CCl4 in 1 ml amounts every ten minutes totaling 12 additions. The reaction product was filtered, washed and dried according to.Example 1 producing the ultra-hard carbonaceous materials of this invention.
1 15~7 --1 o--Example 11 A melt system comprised of 42 g of LiCl and 134 g of AlCl3 was prepared as per Example 1 to which 5.76 g of Al4C3 having a -270 mesh size was added. At a starting temperature of approximately 236C, Freon 11 ~CCl3F) was added in 1 ml amounts every five minutes totaling 23 additions. The reaction product was fil-tered, washed and drièd according to Example 1 produc-ing the ultra-hard carbonaceous materials of the present invention.
Example 12 The melt system of Example 1 was prepared to which approximately 2.88 g of A14C3 was added having a -270 mesh at 242C. Chlorine gas was then bubbled into the hot melt system at a rate of 0.05 cubic feet per hour for 1/2 hour. The rate was then increased to 0.1 cubic feet per hour for the next 2-1/2 hours amounting to a total chlorine addition of 10.7 liters. The reac-tion product was filtered, washed and dried as was shown in Example 1 producing ultra-hard carbonaceous particles according to the present invention.
Example 13 A new melt system was prepared by placing 29.2 g of NaC1 in a flask which was heated to 180~C under vacuum for 2 hours and which was allowed to stand overnight under full vacuum. With mechanical stirring under an argon blanket, 67 g of AlCl3 was added to complete the melt system. To this melt was added
2.88 g of Al4C3 and, as a second reactant, 1 ml of CCl4 was added every 10 minutes to a total of 13 additions. The temperature was maintained above 300C
producing a reaction product which was filtered, washed and dried according to Example 1 producing the ultra-hard carbonaceous particles of the present invention.
Example 14 A new melt system was prepared by placing 37.3 g of KCl in a flask which was heated at full vacuum to 180C for 2 hours. The KCl was maintained at full vacuum overnight and, under mechanical stirring, 67 g of AlCl3 was then added to complete the melt. Approxi-mately 2.88 g of Al4C3 was then added, which was reacted with CCl4 which was in turn added in 1 cc amounts every 10 minutes to a total of 13 additions.
As in Example 13, the temperature was maintained above 300C producing a reaction product which was filtered, washed and dried according to Example 1. The reaction produced ultra-hard carbonaceous particles according to the present invention.
Example 15 To the melt system prepared according to Example 1 was added 2.88 g of A14C3 which was reacted with CC12F2 at a rate of 0.1 cubic feet per hour. The temperature was maintained between 230-245C while the CCl2F2 was bubbled into the system for 2 hours. At the end of these additions, the reaction product was filtered, washed and dried according to Example 1 yielding ultra-hard carbonaceous particles according to the present invention.
Example 16 A melt system according to Example 1 was prepared.
At a temperature of approximately 247C, 2.88 g of Al4C3 was added and reacted with CC12F2 which was introduced into the hot melt system at a rate of 0.1 cubic feet per hour for 4 hours. The temperature was maintained at approximately 238C producing a reaction product which was filtered, washed and dried and which was in the nature of ultra-hard carbonaceous particles.
;
1 1~6267 Example 17 A melt system according to Example 1 was prepared.
To this was added approximately 2.9 g of Al4C3 and 20 mg of tO percent FeS in NaCl, which was heated for an additional 15 minutes. A second reactant comprising CHBr3 was added in 0.5 ml intervals every five minutes to a total of 7.0 ml. The reaction product was fil-tered, washed and dried producing ultra-hard carbona-ceous particles according to the following equation:
A14C3 + 4CHBr3 )4AlBr3 + 6C + CH4 Example 18 To the melt prepared according to Example 1 was added 1.5 g of Al4C3 and 20 mg of FeS in NaCl. A
s~econd reactant comprising CH2I2 was added every five minutes in 0.5 ml amounts with refluxing until a total of 5 ml had been added. The product was then washed and dried producing ultra-hard carbonaceous particles according to the following reaction:
6CH2I2 + Al4C3 ~4AlI3 + 3CH4 + 6C
As can be seen from the above working examples, ultra-hard carbonaceous particles can be produced as the product of a reaction of a metal carbide selected from the group consisting of Al4C3 and Be2C
with a member selected from the group consisting of n A (4-n)-A~ C2Hn,xA.Y(6-n~)-A~ C2Hn"XA"Y (4 and X2 wherein X and Y are different halogens selected from the group consisting of chlorine, bromine, iodine and fluorine, and wherein A is an integer from 0 to 4, A' is an integer from 0 to 6 and A" i5 an integer from 0 to 4, and wherein n is an integer from 0 to 4, n' i9 an integer from 0 to 6 and n" is an integer from 0 to 4, wherein A, A', A", n, n' or n" is the same integer in any particular member selecteA and wherein n + A = 4, n' + A' = 6 and n" + A" = 4. In actual reactions which were carried out, the reaction energy was found to be enormously favorable and more than 100 times as great per carbon atom as the graphite-carbon interconversion energy. The need for extremes in either temperature or pressure, conditions which were employed by synthetic diamond and other hard carbonaceous particle fabrica-tors, have been completely eliminated in practicing the present invention.
The reaction was carried out in a hot melt system comprised of a molten solution of more than one metal halide wherein the metals are seldcted from the group consisting of Group I, Group II and Group III metals of the periodic table and the halides are selected from the group consisting of chlorine, bromine, iodine and fluorine. The present invention also contemplates the use of nucleating agents with lattice constants as close to that of diamond. For example, very fine particles of FeS, Cu, or diamond itself may be employed. The present invention also contemplates the use of a catalyst such as I2.
Each of the ultra-hard carbonaceous products produced according to the above-recited examples was tested for hardness and corresponding abrasiveness.
The commonly used Moh's Scale from 1-10, where 1 is talc, 7 is quartz, 9 is corundum and 10 is diamond, is purely a ranking by scratch ability and has no relative quantitative significance. In some grinding tests, diamond is at least 100 times as hard as corundum.
When one places a small amount of powdered abrasive on a glass slide, moistens the powder, rubs this against another glass slide for a few seconds, washes the slide and then observes the results under a microscope by reflective light, marked quantitative and qualitative differences between abrasive materials are notable.
1 1~6267 Corundum or carborundum as fine grits or powders yield, at most, short grooves. These abrasives crumble relatively rapidly and the glass slide quickly assumes a frosted appearance. Fine diamond grits and the carbonaceous powders of the present invention behave totally differently and yield long, highly character-istic, meteoric grooves. Each of the hard carbonaceous products of the above-recited examples displayed at least some tendency to yield these characteristic meteoric grooves when tested.
producing a reaction product which was filtered, washed and dried according to Example 1 producing the ultra-hard carbonaceous particles of the present invention.
Example 14 A new melt system was prepared by placing 37.3 g of KCl in a flask which was heated at full vacuum to 180C for 2 hours. The KCl was maintained at full vacuum overnight and, under mechanical stirring, 67 g of AlCl3 was then added to complete the melt. Approxi-mately 2.88 g of Al4C3 was then added, which was reacted with CCl4 which was in turn added in 1 cc amounts every 10 minutes to a total of 13 additions.
As in Example 13, the temperature was maintained above 300C producing a reaction product which was filtered, washed and dried according to Example 1. The reaction produced ultra-hard carbonaceous particles according to the present invention.
Example 15 To the melt system prepared according to Example 1 was added 2.88 g of A14C3 which was reacted with CC12F2 at a rate of 0.1 cubic feet per hour. The temperature was maintained between 230-245C while the CCl2F2 was bubbled into the system for 2 hours. At the end of these additions, the reaction product was filtered, washed and dried according to Example 1 yielding ultra-hard carbonaceous particles according to the present invention.
Example 16 A melt system according to Example 1 was prepared.
At a temperature of approximately 247C, 2.88 g of Al4C3 was added and reacted with CC12F2 which was introduced into the hot melt system at a rate of 0.1 cubic feet per hour for 4 hours. The temperature was maintained at approximately 238C producing a reaction product which was filtered, washed and dried and which was in the nature of ultra-hard carbonaceous particles.
;
1 1~6267 Example 17 A melt system according to Example 1 was prepared.
To this was added approximately 2.9 g of Al4C3 and 20 mg of tO percent FeS in NaCl, which was heated for an additional 15 minutes. A second reactant comprising CHBr3 was added in 0.5 ml intervals every five minutes to a total of 7.0 ml. The reaction product was fil-tered, washed and dried producing ultra-hard carbona-ceous particles according to the following equation:
A14C3 + 4CHBr3 )4AlBr3 + 6C + CH4 Example 18 To the melt prepared according to Example 1 was added 1.5 g of Al4C3 and 20 mg of FeS in NaCl. A
s~econd reactant comprising CH2I2 was added every five minutes in 0.5 ml amounts with refluxing until a total of 5 ml had been added. The product was then washed and dried producing ultra-hard carbonaceous particles according to the following reaction:
6CH2I2 + Al4C3 ~4AlI3 + 3CH4 + 6C
As can be seen from the above working examples, ultra-hard carbonaceous particles can be produced as the product of a reaction of a metal carbide selected from the group consisting of Al4C3 and Be2C
with a member selected from the group consisting of n A (4-n)-A~ C2Hn,xA.Y(6-n~)-A~ C2Hn"XA"Y (4 and X2 wherein X and Y are different halogens selected from the group consisting of chlorine, bromine, iodine and fluorine, and wherein A is an integer from 0 to 4, A' is an integer from 0 to 6 and A" i5 an integer from 0 to 4, and wherein n is an integer from 0 to 4, n' i9 an integer from 0 to 6 and n" is an integer from 0 to 4, wherein A, A', A", n, n' or n" is the same integer in any particular member selecteA and wherein n + A = 4, n' + A' = 6 and n" + A" = 4. In actual reactions which were carried out, the reaction energy was found to be enormously favorable and more than 100 times as great per carbon atom as the graphite-carbon interconversion energy. The need for extremes in either temperature or pressure, conditions which were employed by synthetic diamond and other hard carbonaceous particle fabrica-tors, have been completely eliminated in practicing the present invention.
The reaction was carried out in a hot melt system comprised of a molten solution of more than one metal halide wherein the metals are seldcted from the group consisting of Group I, Group II and Group III metals of the periodic table and the halides are selected from the group consisting of chlorine, bromine, iodine and fluorine. The present invention also contemplates the use of nucleating agents with lattice constants as close to that of diamond. For example, very fine particles of FeS, Cu, or diamond itself may be employed. The present invention also contemplates the use of a catalyst such as I2.
Each of the ultra-hard carbonaceous products produced according to the above-recited examples was tested for hardness and corresponding abrasiveness.
The commonly used Moh's Scale from 1-10, where 1 is talc, 7 is quartz, 9 is corundum and 10 is diamond, is purely a ranking by scratch ability and has no relative quantitative significance. In some grinding tests, diamond is at least 100 times as hard as corundum.
When one places a small amount of powdered abrasive on a glass slide, moistens the powder, rubs this against another glass slide for a few seconds, washes the slide and then observes the results under a microscope by reflective light, marked quantitative and qualitative differences between abrasive materials are notable.
1 1~6267 Corundum or carborundum as fine grits or powders yield, at most, short grooves. These abrasives crumble relatively rapidly and the glass slide quickly assumes a frosted appearance. Fine diamond grits and the carbonaceous powders of the present invention behave totally differently and yield long, highly character-istic, meteoric grooves. Each of the hard carbonaceous products of the above-recited examples displayed at least some tendency to yield these characteristic meteoric grooves when tested.
Claims (12)
1. Ultra-hard particles composed largely of carbon on an atomic basis comprising the product of the reaction of a metal carbide selected from the group consisting of Al4C3 and Be2C with a member selected from the group consisting of CHnXAY(4-n)-A' C2Hn'XA'Y(6-n')-A'' C2Hn"XA"Y(4-n")-A" and X2 wherein X
and Y are different halogens selected from the group consisting of chlorine bromine, iodine and fluorine, and wherein A is an integer from 0 to 4, A' is an integer from 0 to 6 and A" is an integer from 0 to 4, and wherein n is an integer from 0 to 4, n' is an integer from 0 to 6 and n" is an integer from 0 to 4, wherein A, A', A", n, n' or n" is the same integer in any particular member selected and wherein n + A = 4, n' + A' = 6 and n" + A" = 4.
and Y are different halogens selected from the group consisting of chlorine bromine, iodine and fluorine, and wherein A is an integer from 0 to 4, A' is an integer from 0 to 6 and A" is an integer from 0 to 4, and wherein n is an integer from 0 to 4, n' is an integer from 0 to 6 and n" is an integer from 0 to 4, wherein A, A', A", n, n' or n" is the same integer in any particular member selected and wherein n + A = 4, n' + A' = 6 and n" + A" = 4.
2. The ultra-hard particles of claim 1 wherein said reaction is carried out in a hot melt system.
3. The ultra-hard particles of claim 2 wherein said hot melt system is comprised of a molten solution of more than one metal halide wherein the metals are selected from the group consisting of Group I, Group II and Group III metals of the periodic table and the halides are selected from the group consisting of chlorine, bromine, iodine and fluorine.
4. The ultra-hard particles of claim 1, 2, or 3 wherein the hot melt system is substantially free of oxidizing anions and hydrogen containing anions.
5. The ultra hard particles of claim 1 wherein the metal carbide is Al4C3.
6. The ultra-hard particles of claim 2 wherein the hot melt system exhibits substantial solvent capability for Al203.
7. The ultra-hard particles of claim 2 wherein the hot melt system is substantially anhydrous and substantially free of hydroxyl groups.
8. The ultra-hard particles of claim 1 wherein a crystal nucleating agent is included in the reactants.
9. The ultra-hard particles of claim 8 wherein the crystal nucleating agent is a member of the group consisting of FeS, Cu and diamond.
10. The ultra-hard particles of claim 3 wherein one of the metal halides comprises AlX3, wherein X is selected from the group consisting of Cl, Br, I and F.
11. The ultra-hard particles of claim 10 wherein the metallic halide is selected from the group consist-ing of alkaline halides and alkaline earth halides.
12. The ultra-hard particles of claim 11 wherein said hot melt comprises a molten solution of AlCl3 and LiCl.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000380198A CA1156267A (en) | 1981-06-19 | 1981-06-19 | Production of ultra-hard particles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000380198A CA1156267A (en) | 1981-06-19 | 1981-06-19 | Production of ultra-hard particles |
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| Publication Number | Publication Date |
|---|---|
| CA1156267A true CA1156267A (en) | 1983-11-01 |
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ID=4120270
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000380198A Expired CA1156267A (en) | 1981-06-19 | 1981-06-19 | Production of ultra-hard particles |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1156267A (en) |
-
1981
- 1981-06-19 CA CA000380198A patent/CA1156267A/en not_active Expired
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