Fabrication of YAG Transparent Ceramics by Two Step Sintering Process

Well dispersed yttrium aluminum garnet (YAG) nanopowders with mean particle size of about 50nm synthesized by modified co-precipitation method were used to sinter YAG transparent ceramics with 0.5wt% TEOS as sintering additive by two step sintering process. The samples were first heated to a higher temperature ranging from 1700 ◦ C to 1800 ◦ C, then cooled down to a lower temperature ranging from 1500 ◦ C to 1600 ◦ C, and held at the lower temperature for 10h. Grain-boundary migration is suppressed and grain-boundary diffusion is promoted during the two step sintering process. When the two step sintering temperatures are 1800 ◦ C and 1550 ◦ C, the microstructure of YAG is homogeneous with average grain size of 6µm without abnormal grain growth and the transmittance of the specimen is 72.0%.