Abstract: The neodymium doped yttrium aluminum garnet (Nd:YAG) powders were synthesized by the low temperature combustion and the transparent ceramic disks with 9mm in diameter and 1mm in thickness were prepared by the vacuum sintering at 1700℃ for 5h after being 300MPa model pressing. The transparent ceramics were characterized by optical transmittance, field emission gun-environment scanning microscope and the study were carried out on the qualitative relationship between the optical transmittance and
microstructure parameters using stereology theory and method. The results show that the optical transmittance of Nd:YAG transparent ceramics with 9mm in diameter and 1mm in thickness is about 45% in visible region and 55% in infrared region and increase with the incidence light wavelength increasing. The optical transmittance increases with three dimensionally corresponding diameter (D_3S ) of grain climbing and reaches the theoretical value of single crystals when D_3S is 20μm. The optical transmittance decreases with the grain and single grain mean specific area enhancing and mean free distance of grains adding.

Key words: neodymium doped yttrium aluminum garnet, transparent ceramics, stereology, microstructureenddocument