The synthesis of TiB2–TiAl3 composites by field-activated combustion

The synthesis of TiB2–TiAl3 composites with TiB2/TiAl3=x molar ratios from x=1.0 to 5.0 were investigated by electric field-activated combustion using elemental powders as reactants. Using amorphous boron powders, composites with x≤2.0 can be synthesized in the absence of a field. Those with 3.0≤x≤5.0 can only be formed in the presence of a field. For all cases, the product contained the desired phases with minor amounts of Ti5Al11. Higher values of x, resulted in relatively higher amounts of this phase. The effect of the use of crystalline boron and the influence of its particle size were also investigated. In the absence of a field, no self-sustaining combustion wave could be initiated even when the smallest particles (<20 μm) were used. Under the influence of an 18 Vcm−1 field, combustion waves were initiated and the products were virtually identical to those obtained with the amorphous boron powders.