Size effect in shock-induced phase transition of TiO₂

Using explosive-driven flyer to compact mixture powders of TiO₂ and copper, two different TiO₂ particle size (60 nm and 1.5 μm) used to investigate the size effect on shock-induced phase transition. XRD, Raman and SEM tests for retrieved powders all confirm Rutile-to-Srilankite phase transition with both sizes, micro-scale TiO₂ high pressure phase transition rate reaches 93%, far higher than the nano-scale phase transition rate, which is only 45%. SEM shows that these shock-treated powders are ellipses within the size range of 0.5~2.0 μm. This result shows that bigger particle size of TiO₂ will facilitate the exposure and detainment of high pressure phase during the shock-induced phase transition of TiO₂.