SYNTHESIS OF MOSI2-XNB AND MOSI2-YZRO(2) COMPOSITES BY THE FIELD-ACTIVATED COMBUSTION METHOD

The effect of an electric of field on the combustion synthesis of MoSi 2-xNb (0 less than or equal to x less than or equal to 0.45) and MoSi2 -yZrO(2) (0 less than or equal to y less than or equal to 0.15) was in vestigated. The velocity of the combustion wave in both composite syst ems increased nearly linearly with an increase in the applied field. C omposites with x greater than or equal to 0.45 and y greater than or e qual to 0.15 can only be synthesized in the presence of a field. Altho ugh, in the absence of a field, the system with x = 0.45 and y = 0.15 can sustain a non-steady combustion wave, the reaction is not complete and only partial conversion to MoSi2 is evident. For the synthesis of pure MoSi2, the field was shown to affect the particle size of the pr oduct. The average particle size decreased when the synthesis was carr ied out under the effect of the field.