Abstract: Chalcogenide based photovoltaic devices cells with good resistance to environmental elements can be formed by direct low temperature deposition of inorganic barrier layers onto the film. A unique multilayer barrier can be formed in a single step when reactive sputtering of the silicon nitride onto an inorganic oxide top layer of the PV device.

Abstract: The present invention is directed to a method for treating discolored natural diamond, especially Type IIa diamond and Type IaA/B diamond with nitrogen as predominantly B centers, for improving its color. The method includes preblocking and preshaping a discolored natural diamond to prevent its breakage in a high pressure/high temperature (HP/HT) press, placing said discolored natural diamond in a pressure transmitting medium which is consolidated into a pill. Next, the pill is placed into a HP/HT press at elevated pressure and elevated temperature within the graphite-stable or diamond-stable range of the carbon phase diagram for a time sufficient to improve the color of said diamond. Finally, the diamond is recovered from said press. Colorless and fancy colored diamonds can be made by this method.

Abstract: The present invention is directed to a method for treating discolored natural diamond, especially Type IIa diamond and Type IaA/B diamond with nitrogen as predominantly B centers, for improving its color. The method includes placing a discolored natural diamond in pressure transmitting medium powder which is consolidated into a pill. Next, the pill is placed into a high pressure/high temperature (HP/HT) press at elevated pressure and elevated temperature within the diamond stable range of the carbon phase diagram for a time sufficient to improve the color of said diamond. Finally, the diamond is recovered from said press. Colorless diamond can be made by this method.

Abstract: A method for treating as as-grown chemical vapor deposited (CVD) starting diamond film having stresses and containing voids, comprises the step of subjecting the diamond film to a temperature of above about 1000.degree. C. and a hydrostatic pressure of above about 3 kilobars.

Abstract: Broadly, the present invention is directed to polycrystalline diamond of improved thermal conductivity. The novel polycrystalline diamond consists essentially of at least 99.5 wt-% isotopically-pure carbon-12 or carbon-13. The inventive polycrystalline diamond is formed from at least 99.5 wt-% isotopically-pure carbon-12 or carbon-13. Single-crystal isotopically-pure carbon-12 and carbon-13 diamond are known to possess improved thermal conductivity. Polycrystalline diamond, however, possesses lower thermal conductivity patterns deleteriously impacted by, for example, impurities, isotopic effects, and grain boundary scattering. In fact, grain boundary scattering would lead the skilled artisan to believe that the thermal conductivity of polycrystalline diamond would be substantially unaffected by the isotopic nature of the diamond itself.

Abstract: In its broadest aspects, the present invention is directed to a method for improving the abrasion resistance of the annular interior surface of an annulus. Such method comprises the steps of (a) placing said annulus heated to an elevated CVD diamond-forming temperature in a vacuum chamber held under reduced pressure; (b) providing a hydrocarbon/hydrogen gaseous mixture within said chamber; (c) at least partially decomposing said gaseous mixture in said chamber; and (d) directing said at least partially decomposed gaseous mixture into said heated annular interior for diamond deposition/growth to occur on said annular interior surface. As noted above, spray nozzles, valves, injectors, wire drawing dies, and like annular products are ideally suited for use in accordance with the precepts of the present invention.

Abstract: Single-crystal diamond consisting of isotopically pure carbon-12 or carbon-13 has been found to have a thermal conductivity higher than that of any substance previously known, typically at least 40% higher than that of naturally occurring IIA diamond. It may be prepared by a method comprising comminution of diamond of high isotopic purity, such as that obtained by low pressure chemical vapor deposition employing an isotopically pure hydrocarbon in combination with hydrogen, followed by conversion of the comminuted diamond to single-crystal diamond under high pressure conditions.

Abstract: An improved two membered substantially crack-free water jet mixing tube of an abrasive water jet cutting device and a method of its preparation. The method comprises chemically vapor depositing diamond layer on a funnel shaped support member to form an inner member of the mixing tube, separating the inner member from the support member, depositing and then cooling an outer member on the outer side of the inner member to produce a compressive stress on the inner member that substantially prevents formation cracks on the inner member. The inner side of the inner member has a smooth bore having a microcrystalline structure and the outer member has a higher coefficient of thermal expansion than diamond. The invention is also directed to a water jet cutting device that incorporates the aforementioned improved substantially crack-free water jet mixing tube.

Abstract: The present invention is directed to the production of single-crystal diamond consisting of isotopically pure carbon-12 or carbon-13. The product is believed to be like that diamond product in application Ser. No. 448,469, but is made by a different method. In the present invention, isotopically pure single-crystal diamond is grown on a single crystal substrate directly from isotopically pure carbon-12 or carbon-13. One method for forming isotopically pure single-crystal diamond comprises the steps of placing in a reaction chamber a single crystal substrate heated to an elevated CVD diamond-forming temperature. A gaseous mixture of hydrogen and a hydrocarbon of isotopically pure carbon-12 or carbon-13 is provided in the chamber. The gaseous mixture then is at least partially decomposed in the chamber to form an isotopically-pure single crystal diamond layer on the single crystal substrate disposed therein.

Abstract: Single-crystal diamond consisting of isotopically pure carbon-12 or carbon-13 has been found to have a thermal conductivity higher than that of any substance previously known, typically at least 40% higher than that of naturally occurring IIA diamond. It may be prepared by a method comprising an initial step of low pressure chemical vapor deposition employing an isotopically pure hydrocarbon in combination with hydrogen, followed by comminution of the diamond thus obtained and conversion thereof to single-crystal diamond under high pressure conditions.

Abstract: The present invention relates to a method for growing diamond on a diamond substrate by chemical vapor deposition. The inventive method comprises alternatingly contacting at elevated temperature said diamond substrate with a gas having the formula C.sub.n X.sub.m and then with a gas having the formula C.sub.l Z.sub.p. X and Z each form single bonds with carbon. X and Z also are reactable to form ZX or a derivative thereof. The Z--X bond is stronger than the C--X bond and also is stronger than the C--Z bond. In the formulas, n, m, l, and p are integers. If C.sub.n X.sub.m and C.sub.l Z.sub.p do not react in the gas phase, then a gas mixture of them can be used to grow diamond instead of the alternating exposure of one and then the other.

Abstract: The present invention enables the diamond coating of stationary elongate objects, such as twist drills, with a continuous uniform film without any motion of the twist drill due to the unexpected superb "throwing power" of a reactor disclosed herein. The CVD diamond reactor includes a vacuum chamber, inlet for feed hydrogen/hydrocarbon mixtures, and an outlet, in conventional fashion.

Abstract: A carbon chalcogenide macromolecular composition prepared from carbon dichalcogenide and to a process for the preparation thereof. A carbon dichalcogenide, for example, carbon disulfide, in entrained in an inert gas, and the mixture formed therefrom is passed over a hot tungsten filament wherein carbon disulfide is degraded into fragments. The fragments are then deposited onto a surface of a non-reactive substrate. The deposited fragments recombine to form the macromolecular composition. A significant characteristic of the composition is its threshold voltage above which its electrical resistance drops precipitously. This characteristic also exhibits a unique temperature dependence. Dopants may be added to the composition to reduce the electrical resistance.

Abstract: The present invention enables the diamond coating of stationary elongate objects, such as twist drills, with a continuous uniform film without any motion of the twist drill due to the unexpected superb "throwing power" of a reactor disclosed herein. The CVD diamond reactor includes a vacuum chamber, inlet for feed hydrogen/hydrocarbon mixtures, and an outlet, in conventional fashion.

Abstract: A carbon chalcogenide macromolecular composition prepared from carbon dichalcogenide and to a process for the preparation thereof. A carbon dichalcogenide, for example, carbon disulfide, in entrained in an inert gas, and the mixture formed therefrom is passed over a hot tungsten filament wherein carbon disulfide is degraded into fragments. The fragments are then deposited onto a surface of a nonreactive substrate. The deposited fragments recombine to form the macromolecular composition. A significant characteristic of the composition is its threshold voltage above which its electrical resistance drops precipitously. This characteristic also exhibits a unique temperature dependence. Dopants may be added to the composition to reduce the electrical resistance.

Abstract: An x-ray tube target has improved heat dissipation by applying a layer of diamond between the focal track and the target body. The diamond layer can be applied directly to a graphite target body, a graphite disc covered with silicon carbide or to a disc composed of an molybdenum alloy such as TZM.