The effect of explosive shocking on the properties of fine titanium oxide TiO2 and zirconium oxide ZrO2 powder was examined. Experiments at two different pressures were conducted on anatase-type TiO2 and monoclinic-rich ZrO2 in which about 14% of the tetragonal phase was contained. The impact pressures induced in the powder by the shocks were estimated to be about 5GPa and 20GPa.
The crystallite sizes of both powders estimated from broadening of the X-ray line became smaller due to the explosive shock treatment. No sign of commiuntion was observed. The average particle diameters of the explosively shocked powders were, larger than those of as-received powders due to sintering. This indicates that smaller crystallite sizes were caused by the shock-induced defects present in the powders, not by small particle diameters.
TiO2 and ZrO2 were respectively densified to 98 and 96% of the theoretical density by the shock compression of 20GPa.
About 30% of anatase-type TiO2 was transformed to rutile-type. The tetragonal phase normally observed at higher temperatures of ZrO2 was all changed to a monoclinic plase by the impact pressure of 5GPa, but about 25% of the tetragonal phase was again produced by the impact pressure of 20GPa.
The sintered density of explosively shocked TiO2 became lower than that of as-received powder. The sintered body of explosively shocked ZrO2 has fewer cracks than that of as-received powder probably because of the existence of the tetragonal phase.
