Size Effect in Raman Spectra of Hydrous Zirconia Particles

Abstract

The Raman spectra of hydrous zirconia particles prepared by hydrolysis of ZrOCl2 were measured. The number of Roman bands and the Roman shift observed for as-prepared hydrous zirconia particles are similar to those observed for the monoclinic crystalline ZrO2 except the width of measured Raman bands are broad. Using high resolution TEM, it was observed that hydrous zirconia particles consist of highly crystallized primary particles of 30A in diameter. These experimental facts indicated that the broadness of Raman bands were resulted from breakdown in K-momentum conservation in small size particles. The Raman bands of hydrous zirconia particles heated up to 900°C became narrower with increasing temperature. TEM observations also showed that the size of heat-treated particles increased with increasing temperature. Therefore, the narrowing in Raman bands is considered as a result of increase in particle size as observed in small particle size crystalline silicon. The relationship between the width of Roman band and the particle size in hydrous zirconia particles was experimentally established.