AFRL and K Systems' DLC Capacitor Shows Improvement with Reduced Size

May 08, 2000 by Jeff Shepard

Although a number of techniques for the deposition of diamond-like carbon (DLC) has evolved, the unique patented process developed by the Air Force Research Laboratory Propulsion Directorate (AFRL, Wright Patterson Air Force Base, OH) and K Systems Corp. (Beavercreek, OH) is claimed to produce extremely high-quality coatings that are free of pin holes, have good surface morphology, superb adhesion to a number of different types of surfaces, high thermal conductivity and are inexpensive to produce. It is claimed that these DLC devices may reduce the weight, size and volume by 50 percent over current state-of-the-art components. Wright Technology Network (Dayton, OH) has received AFRL funding to commercialize this capacitor technology.

The rolled capacitor devices, formed of the patented invention using 0.5 micron of DLC as the dielectric material on each side of the capacitor-grade aluminum foil, have a size that is ten times smaller than a conventional rolled capacitor. Such a capacitor is electronically stable in temperatures from about -55 degrees to 200 degrees C. These capacitors are designed to have a high direct-current resistance, a high thermal conductivity, a high-voltage breakdown strength of greater than 15KV/mil and capacitance on the order of ten of microfarads.

The high-energy density capabilities of these DLC capacitors are designed to enable electrically driven aircraft accessories, such as engine-mounted actuators for an all-electric engine and remotely mounted flight control actuators.

The research and development of this project is currently funded by the AFRL Propulsion Directorate through a Phase II, small-business, innovative research contract to K Systems Corp. A prototype DLC capacitor manufacturing facility has been constructed at the AFRL Propulsion Directorate.

The DLC capacitors include high-temperature alternating current or direct current power-filter capacitors, and high-temperature snubber and energy-storage capacitors. The capacitors may also be used as high-power filters and high-pulse rate switching capacitors.