Transparent sesquioxide ceramics, e.g. Y<sub>2</sub>O<sub>3</sub> and Sc<sub>2</sub>O<sub>3</sub> are being developed as alternatives to yttrium aluminum garnet
(YAG) for high-power solid-state laser systems. In this work, we present the synthesis of these sesquioxide nanopowders
by precipitation techniques and the subsequent processing of these nanopowders into sub-micron transparent ceramics
using a modifying two-step sintering approach. These transparent ceramics exhibited equivalent transparency to that of
analogous single crystals. The microhardness and fracture toughness of the modified two-step sintered ceramic exceeded
those of conventionally sintered ceramic by 25% and 70%, respectively.
This paper discusses the hydrothermal synthesis of doped and undoped Sc<sub>2</sub>O<sub>3 </sub>single crystals as well as Y<sub>2</sub>O<sub>3</sub> and Sc<sub>2</sub>O<sub>3</sub>
nanoparticles as high purity precursors to polycrystalline laser hosts.