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 field. Materials with starting composition ranging from 6 to 30 wt. % Si were investigated by the method of field-activated combustion synthesis (FACS). A threshold field value was required to initiate a self-sustaining wave; the threshold value depended on composition. It was shown that the level of the applied field can influence the mechanism of silicide formation. The silicide W₅Si₃ could be formed only at relatively high field values while WSi₂ can be formed at any field. The effect of the field on the silicide formation is discussed in terms of its role in liquid phase formation.