DIAMOND FIBERS FOR HEAT SINKS*DIAMOND FIBERS FOR THERMAL ENERGY MANAGEMENT

DIAMOND FIBER, WHEN A HIGHLY-GRAPHITIC CORE FIBER OF 1 TO 5 MICRONS HAS A DIAMOND COATING OF 2 TO 10 MICRONS, IS A HYBRID FIBER WITH PREDOMINATELY DIAMOND PROPERTIES. THIS ENABLES TAILORING OF FIBER COEFFICIENTS OF THEMAL CONDUCTIVITY (CTE) TO ALLOW MATCHING TO THE CTE OF DEVICES MOUNTED ON A COMPOSITE FABRICATED FROM SUCH FIBERS. THERMAL CONDUCTIVITY OF THE POLYCRYSTALLINE FIBERS IS EXPECTED TO BE ISOTROPIC, AT 600 W/M-K. AS SUGGESTED BY EXPERIMENTS 20 YEARS AGO, A VLS PROCESS UTILIZING 1990 TECHNOLOGY FOR CVD DIAMOND PRODUCTION, COUPLED WITH A VLLS METHOD FOR VAPOR GROAN CARBON FIBER TECHNOLOGY CAN PRODUCE WHISKERS WITH MORPHOLOGY LIKE DIAMOND WHISKERS. EDAX SHOWS THESE FIBERS TO BE PURE CARBON. IF CONFIRMED TO BE SINGLE CRYSTAL DIAMOND, THIS FIBER COULD BE USEFUL IN RADIATION-HARD FIBER OPTICS AS WELL AS A COMPOSITE REINFORCEMENT WITH ISOTROPIC THERMAL CONDUCTIVITY IN EXCESS OF 2000 W/M-K, AND A CTE SIMILAR TO SILICON.