摘要:
Chemical vapor deposition method for producing a fine grained smooth growth surfaced diamond film on a substrate employs a hydrogen/hydrocarbon gaseous atmosphere containing an amount of nitrogen effective to inhibit the growth of the diamond grains deposited on the substrate.
摘要:
Broadly, the present invention is directed to improving a chemical vapor phase deposition (CVD) method for synthesis of diamond wherein a hydrocarbon/hydrogen gaseous mixture is subjected to a combustion flame in the presence of oxygen to at least partially decompose the gaseous mixture to form CVD diamond. The improvement in process comprises subjecting said combustion flame to one or more of dielectric heating, d.c. discharge, or a.c. discharge. Dielectric heating can be accomplished by subjecting the combustion flame to microwave (MW) frequency discharge or radiofrequency (RF) discharge. By superimposing dielectric heating or d.c./a.c. discharge plasma generation on combustion flame process, the carbon utilization rate of the combustion flame process should improve substantially. As noted above, given the low carbon utilization rate for combustion flame techniques already, small percentage improvements in the carbon utilization rates translate into substantial cost savings in generation of CVD diamond by such combustion flame technique.
摘要:
Surgery is performed with pulsed heat means that selectively destroys tissue in a region within a patient. The size of the region destroyed is dependent upon the frequency of the pulses of the pulsed heat means and thermal conductivity of the tissue of the patient. The pulsed heat means can be a coherent optical source (80) that is guided by laser fiber to the tissue to be destroyed. In another embodiment the pulsed heat means is a focussed ultrasound transducer that dissipates ultrasonic energy at a focal point within the region of tissue to be destroyed. A magnetic resonance imaging system (10,20,30) employing a temperature sensitive pulse sequence creates an image of the tissue and the region being heated to allow a surgeon to alter the position of the pulsed heat means or vary the pulse frequency.
摘要:
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. The improvement for coating with CVD diamond the entire outer surface of at least a portion of a plurality of stationary elongate objects comprises disposed within said reactor, an elongate metal tube having a plurality of apertures for holding elongate objects disposed radially inwardly and having a cooling pipe in thermal contact with and disposed about the outside of said metal tube; and a filament running within said tube along its lengthwise extent and being in electrical connection with the source of voltage for heating said filament to a temperature adequate to initiate hydrocarbon disassociation, the portions of said elongate object within said tube surrounding said filament being heated thereby.
摘要:
The present invention is addressed to a method for making diamond workpieces which comprises the steps of placing in a chamber a pattern heated to an elevated CVD diamond-forming temperature, the pattern being the negative of the workpiece. A hydrocarbon/hydrogen gaseous mixture is provided within the chamber in the next step. The gaseous mixture then is at least partially decomposed in the chamber to form/deposit the CVD diamond layer on a surface of the pattern. In the final step, the CVD diamond layer is removed from the pattern to form the workpiece which possesses the surface characteristics of the surface of the pattern upon which it was formed. Appropriate workpieces that can be made in accordance with the inventive process include convergent, divergent, and flat optical mirrors; nozzles, wire dies, and tubular shaped workpieces; curved, angular, and re-entrant shaped workpieces useful in grinding, cutting, wear, and other applications; and a variety of additional products.
摘要:
A method is provided for making a single crystal diamond by chemical vapor deposition which utilizes a single crystal seed of a HPHT diamond and a hydrocarbon-hydrogen mixture, such as methane-hydrogen mixtures containing a effective amount of a metallocene, such as ferrocene. It has been found that the use of a metallocene in the hydrocarbon-hydrogen mixture suppresses secondary nucleation of polycrystalline diamond.