THE INFLUENCE OF AN ELECTRIC-FIELD ON THE MECHANISM OF COMBUSTION SYNTHESIS OF TUNGSTEN SILICIDES

The synthesis of tungsten silicides by self-propagating combustion has been successfully accomplished under the influence of an electric fie ld. Materials with starting composition ranging from 6 to 30 wt. % Si were investigated by the method of field-activated combustion synthesi s (FAGS). A threshold held value was required to initiate a self-susta ining wave; the threshold value depended on composition. It was shown that the level of the applied field can influence the mechanism of sil icide formation. The silicide W5Si3 could be formed only at relatively high field values while WSi2 can be formed at any held. The effect of the field on the silicide formation is discussed in terms of its role in liquid phase formation.