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thermal expansion as well as desirable strength and weight characteristics of metal and ceramic matrix cast components. DOD - Strategic Defense Initiatives Organization
CHEMICAL VAPOR DEPOSITION DIAMOND COATINGS FOR OPTICS. ELECTRONICS AND MEDICAL APPLICATIONS
Diamond films can be deposited on suitable substrates using the chemical vapor deposition process (CVD). In CVD, the substrate is placed inside a low pressure chamber and heated to approximately 1000C. A metal filament at incandescent temperatures heats a mixture of hydrogen gas and a hydrocarbon vapor. Hydrogen molecules are split into discrete atoms and the hydrocarbon molecules break into fragments. This hot vapor mixture is introduced over the substrate, resulting in the deposition of a film of diamond. Processing conditions are carefully controlled to ensure the reactive hydrocarbon vapors result in the desired diamond film rather than another, undesirable form, graphite. The diamond film can coat a wide range of substrates, including those intended for optical windows, micro-electronics, and surfaces required for hard wear and sharpness, such as surgical instruments.
Crystallume, Inc., of Menlo Park, CA, originally developed the CVD diamond coating technique for the Strategic Defense Initiative Organization (SD10) to coat optical windows on high speed atmospheric missiles. The diamond provided the desired band-pass characteristics through the window, while protecting against the severe environment of hypersonic flight. This technology was quickly applied to other applications, both commercial and military, which require the superior optical, electrical, mechanical and thermal qualities of diamonds. Current development is underway to adapt the CVD diamond coating process to tailor it to the various specific applications, which require different substrates, film dept, crystal size, and other variables of both the process and its application.
USE AND BENEFITS
The first commercial application, introduced by Crystallume, Inc., was an ultrathin X-ray detector window on an analytical X-ray instrument. Other applications quickly followed, including synchrotron windows, medical instrument windows, and X-ray lithography mask membranes for integrated circuit manufacturing. The superior electrical properties of diamond are being applied to active electronic devices, such as field effect transistors. Diamond's friction and wear characteristics are also suitable for uses in tooling, bearing surfaces, cutting surfaces and engine components. Thermal conductivity characteristics of large area CVD diamond heat sinks also offer solutions to heat management problems in electronic applications which require carefully managed heat loads, such as high speed devices, power transistors and dense packaging schemes. DOD - Strategic Defense Initiatives Organization
MAGNETIC SUSPENSION IN CATARACT TREATMENT
A technology originally developed for the Strategic Defense Initiative (SDI) to accurately measure extremely short, rapid pulses of small rocket motors has been adapted for a medical application. The basis of this technology uses miniaturized, extremely accurate pointing and very precise control of magnetic devices. Objects to be suspended in the measurement device use attached pieces of vanadium Permandur inside an electromagnet. Position in the electromagnet is sensed by proximity sensors and adjustments to the electromagnet current are made 3000 times per second to keep the test article in the desired position.
Aura Systems, Inc., the original designer of the magnetic suspension system, announced in late 1989 that the technology was being adapted to a revolutionary new cataract removal procedure. The technique, called the Kelman ElectroMagnetically-Assisted Surgical Technique, or KELMAST, uses tiny magnetic bead injected by syringe into the cataract. By means of the Aura magnetic suspension and control apparatus, a surgeon precisely controls the position and movement of the magnetic bead. The bead is maneuvered in the cataract, pulverizing it. The bead and cataract particles are withdrawn by syringe. USE AND BENEFITS Cataract procedures grow in number every year and are expected to reach four million in ten years. "The use of the KELMAST procedure is expected to be less invasive, less traumatic and more surgically precise than alternate cataract procedures,' according to information quoting Dr. Kelman, the inventor. It also is expected to retain the eye's focusing ability, a shortfall of other procedures. Two years of animal testing lie ahead before approval for use on human subjects. DOD - Strategic Defense Initiatives Orgnization
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"PUTTING TECHNOLOGY TO WORK - 1990"
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