Influence of ammonium sulfate on YAG nanopowders and Yb:YAG ceramics synthesized by a novel homogeneous co-precipitation method

Homogeneous and dispersed Y3Al5O12 (yttrium aluminum garnet, YAG) nanopowders were synthesized via a homogeneous co-precipitation method from the mixed solutions of yttrium nitrate, aluminum nitrate and a small amount of ammonium sulfate using hot urea as the precipitant. The method has the superiorities that co-precipitation of cations is ensured and continuous decomposition of the hot urea is achieved to obtain the narrow size distribution particles. The addition of small amount of ammonium sulfate surfactant, although has no influence on YAG garnet phase formation, has significant effect on dispersion, particles distribution and sinterability of the resultant YAG and Yb:YAG powders. Compared with the undoped sample, the green body of Yb:YAG doped with ammonium sulfate has higher total shrinkage, linear shrinkage rate and relative density through sintering at 1600 degrees C. The resultant Yb:YAG powders can be sintered into transparent ceramics at 1700 degrees C through vacuum sintering. The influence of the sulfate ions on characteristics of the resultant powders was thoroughly studied. (C) 2018 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.