Borfaser mit Antidiffusionsueberzug,Verfahren und Vorrichtung zu ihrer Herstellung

摘要

1334476 Coating boron filaments with boron carbide FRANCE ARMED FORCES - MINISTER OF 25 April 1972 [11 May 1971] 19079/72 Heading C7F A boron filament, preferably a tungsten boride core with a boron coating, is coated with a B 4 C layer 15 micron maximum thickness by heating the filament to 900-1300‹C. in a gas mixture of H 2 , a hydrocarbon and a boron halide. The halide is preferably BCl 3 but may also be a fluoride or bromide and the hydrocarbon is preferably methane. The boron filament ions fed into glass reaction tube 1 via passage 4 in insulating plugs 5 at each end of the tube. The passages 4 are supplied with Hg via conduit 7 which acts as an electrical contact for electrical resistance heating of the filament and as a liquid seal for the tube. The halide and H 2 are supplied by conduit 9, the hydrocarbon via conduit 12 and the gases are exhausted at 8. A W filament is preferably borided with BCl 3 +H 2 in a first reaction tube prior to passing to the B 4 C reaction tube.