A method to simultaneously synthesize and consolidate the silicide NiSi₂and the composite NiSi₂-20vo1.%Nb from powders of Ni, Si, and Nb was investigated. Combustion synthesis was carried out under the combined effect of an electric field and mechanical pressure. The final density of the products increased nearly linearly with the applied pressure. Highly dense NiSi₂and NiSi₂20vol.%Nb with relative densities of up to 97% were produced under the simultaneous application of a 60㎫ pressure and a 3000A current on the reactant powders. The respective Vickers microhardness values for these materials were 6.0 and 5.8 ㎬. From indentation crack measurements, the fracture toughness values for NiSi₂and NiSi₂20vol.%Nb were calculated to be 3.3 and 4.7㎫·m^½, respectively.