Carbotherma1 synthesis of binary (MX) and ternary (M1, M2X) carbides, nitrides and borides from polymeric precursors

Abstract

Polymeric precursors to a wide range of non-oxide ceramics have been synthesized by reacting metal alkoxides with a range of polyhydric and monohydric alcohols (transesterification). The choice of alcohols controls the form of the polymer and the stoichiometry of the coke produced by charring the polymer in an inert atmosphere. The metal oxide and carbon in the cokes are shown to be very intimately mixed, so that subsequent carbothermal reduction proceeds at reduced temperatures, leading to products of high purity and fine particle size. By incorporating more than one metal in the precursor it is possible to produce ceramic alloys at significantly lower temperatures than conventional means allow.