Preparation of refractory nitride fibers by thermal decomposition of transition metal (Ti, Nb) alkoxide-cellulose precursor gel fibers in NH3 atmosphere

Precursor gel fibers have been prepared by extruding cellulose acetate spin ning solutions into transition metal (Ti, Nb, Ta) acetone solution as a coa gulation bath. Gel formation must be due to the coordination of metal to OH and CO groups on the pyranose ring. The resultant gel fibers have been con verted into nitride fibers by pyrolyzing the precursor in NH3 gas flow at t emperatures lower than for powder processing. The precursor gel can give a molecular scale mixture of metal and carbon sources. NbN fiber gave a super conductance at around 13 K. (C) 2001 Kluwer Academic Publishers.