Combustion synthesis of porous titanium microspheres

The synthesis of titanium porous microspheres by a combustion technique was studied under an argon atmosphere by using a TiO₂ − 2.5Mg reactive mixture. The precursor, a fine TiO₂ powder, was thermally treated in the range 600–1300 °C prior to the combustion experiments. TiO₂ microspheres whose diameters were between 10 and 50 μm were obtained from precursor particles annealed in the range 900–1100 °C. A biphase product consisting of Ti and MgO phases was obtained when the TiO₂ microspheres were reduced with Mg. The spherical morphology of the final particles was retained despite the relatively high combustion temperatures (1630–1670 °C) used in this study. Moreover, porous titanium microspheres were obtained when the MgO particles were dissolved using acid leaching. Scanning electron microscopy (SEM) images of the microspheres suggested that the spherical structure contained ∼0.5–2.0-μm-diameter porous windows. The Brunauer–Emmett–Teller (BET) surface area of the Ti microspheres was determined to be 2.8 m² g⁻¹.