Method of producing refractory monocrystalline boron structures

Claim 1

THE METHOD OF PRODUCING MONOCRYSTALLINE BORON STRUCTURES WHICH COMPRISES PASSING A MIXTURE OF A BORON HALIDE AND HYDROGEN IN CONTACT WITH HEATED ELONGATED FILAMENTARY SUBSTRATE OTHER THAN BORON MAINTAINED AT A TEMPERATURE IN THE RANGE FROM ABOUT 1100*K. TO SOMEWHAT ABOVE 1600*K. BUT BELOW THE MELTING POINTS OF BORON AND THE SUBSTRATE TO OBTAIN A MASSIVE DEPOSIT OF BORON ON THE SUBSTRATE, CONTAINING SUCH DEPOSITION OF BORON UNTIL A ROD CONSISTING OF A PREPONDERANT AMOUNT OF BORON ON THE FILAMENTARY SUBSTRATE IS FORMED, SUBJECTING THE ROD THUS OBTAINED TO LOCALIZED HEATING BY ELECTRON BOMBARDMENT TO A TEMPERATURE ABOVE THE MELTING POINT OF THE BORON TO FORM A LOCAL ZONE OF MOLTEN BORON EXTENDING TRANSVERSELY ACROSS THE ROD AND ADVANCING THE LOCALIZED ZONE OF MOLTEN BORON LONGITUDINALLY ALONG THE ROD TO SEGREGATE THE MATERIAL OF A FILAMENTARY SUBSTRATE IN AN END PORTION OF THE ROD.