Hot isostatic pressing of optically active Nd:YAG powders doped by a colloidal processing route

In this work, 1 at.% Nd doped Yttrium Aluminum Garnet Y3Al5O12 (YAG) nano-sized powder prepared by colloidal route was investigated thoroughly concerning agglomeration control and preparation of transparent ceramic by post-HIP. Electrostatic and mechanical deagglomeration process followed by freeze-drying turned out to be an effective method to alleviate agglomeration, yielding a powder with a homogeneous particle size distribution around 100 nm. Transparent Nd:YAG ceramic samples have been successfully prepared by post-HIP without the aid of sintering additives. The optical properties varied markedly with the sintering and hot isostatic pressing conditions used. In-line transmittance values of 56% at 680 nm and close to 80% in the infrared region were recorded.