SYNTHESIS OF MONODISPERSE ZRO2 PARTICLES IN POLYOXYETHYLATED NONIONICREVERSED MICELLES

The solubilization region of sulfuric acid in a cyclohexane solution o f polyoxyethylene(6)nonylphenyl ether can be divided into three realms , i.e. reversed micelle, swollen micelle and water/oil (W/O) microemul sion, depending on the solubilized state of water. Monodisperse spheri cal particles are found to be produced by hydrolyzing zirconium tetra- n-butoxide in the reversed and swollen micelle, but in the W/O microem ulsion their size is broadly distributed. FT-IR and X-ray diffraction measurements have revealed that particles in all realms contain sulfat e ions, but the ions are easily removed by washing in ammonia solution and the washed particles are amorphous hydrated ZrO2. Further, it has been determined that crystalline ZrO2 particles can be obtained by ca lcinating the washed particles at 800 degrees C.