Formation of NbC and TaC from Gel-Derived Precursors

摘要

Binary hydrogels, in which a niobium or tantalum oxide gel and a pyrolysable organic compound are combined, were prepared as preceramic materials. Carbonaceous gel or saccharose is used as the Organic gel constituent, and alkoxides or peroxo Acids are the starting materials for the transition Metal component. Under pyrolysis at 600-700 deg. C, The gels are transformed into carbide precursors in Which a reactive carbon and finely dispersed oxide Particles are mixed intimately. The subsequent Carbothermal reduction proceeds at lower tempera- Tures compared to physical mixtures of oxides and Carbon black.