Formation of Acicular Monoclinic Zirconia Particles under Hydrothermal Conditions

Acicular monoclinic ZrO 2 , particles were prepared by hydrothermal treatmentat 250°C using sulfuric acid solutions containing zirconium ions. The formation process and morphology of the ZrO 2 , particles were investigated. Two types of acicular monoclinic Zr0 2 , particle morphologies were obtained, both elongated in the 〈001〉 direction, and the range of acicular ZrO 2 , particle sizes changedfrom 0.3 to 1.3 μ m with hydrothermal conditions. Addition of MgSO 4 , to the starting solution promoted the crystallization of the monoclinic ZrO 2 , particles.