Application of stereology on microstructure of neodymium-doped yttrium aluminum garnet (Nd:YAG) transparent ceramics

Stereology was applied to study quantitative relationship between stereological parameters in three-dimensional Euclidean space and light transmittance of Nd:YAG ceramics prepared by the vacuum sintering at 1700 deg. C for 5 h. The ceramic materials were characterized by light transmittance, field emission gun-environment scanning microscope. The micrographs of ceramic surface were analyzed by the metallographic software to obtain the frequency distribution of grains. It was found that the transmittance of Nd:YAG 1 mm in thickness is about 45% and 58% in visible and near-infrared wavelength, respectively. The transmittance linearly increases with increasing equivalent sphere diameter and reaches theoretical value of single crystal when the equivalent sphere diameter is 20 μm. The transmittance decreases with increasing of mean specific area per unit volume of grain and discrete grains and mean free distance