Metastabilization of Tetragonal Zirconia by Doping with Low Amounts of Silica

摘要

Nanocrystalline tetragonal zirconia was obtained from ZrOCl_2 via the modified forced hydrolysis method combined with aging of the hydrous amorphous precipitate in the mother liquor at 100 °C for 48 h (pH = 9.3). The role of the precipitation and aging temperatures in the metastabilization of the tetragonal ZrO_2 polymorph is discussed in terms of the structural and textural data of the resultant oxide. The influence of low concentrations of silica (0.01 - 0.35 wt. % Si), spontaneously leached from the glass vessel or intentionally introduced to the parent solution, was shown to be a vital factor, controlling the phase composition of the final prepared zirconia. Using the concepts of zirconium aquatic chemistry, this effect was explained by incorporation of silicates into hydrous zirconia protostructures.