A PLASMA ASSIST CVD PROCESS FOR PRODUCING TIB(2) AND OTHER CERAMIC MULTIFILAMENT TOWS

THERE IS A VERY LARGE PENT-UP DEMAND FOR ADVANCED HIGH PERFORMANCE HIGH TEMPERATURE INTERMETALLIC COMPOSITES WHICH IS LIMITED BY THE AVAILABILITY OF AN ECONOMICAL SMALL DIAMETER CERAMIC FIBER WITH GOOD STRENGTH RETENTION > OR - 1400 DEG C. COMMERCIALLY AVAILABLE CERAMIC FIBERS PRODUCED AS MONOFILAMENT BY CVD OR PYROLYSIS OF POLYMER PRECURSOR HAVE ONE OR MORE FAULTS OF POOR STRENGTH RETENTION ABOVE 800 DEG C, LOW MODULUS, LARGE DIAMETER AND ARE QUITE EXPENSIVE. PLASMA ASSIST CVD OFFERS THE POTENTIAL OF DEPOSITING VERY FINE GRAIN DEPOSITES ON MULTIFILAMENT SMALL DIAMETER SUBSTRATE PRODUCING FIBERS IN THE SIZE RANGE OF 10-50 MICRONS WHICH SHOULD HAVE THERMAL STABILITY OF 1400 DEG C. A STATISTICAL EXPERIMENTAL PROGRAM IS PROPOSED FOR DEVELOPING ECONOMICAL THERMALLY STABLE MULTIFILAMENT TIB(2), TIB AND TIC CERAMIC FIBERS UTILIZING PLASMA ASSIST CVD.