Second phase with content yttrium oxide in optical ceramics
The second phase with the content of below the X-ray detection threshold in transparent Nd<sup>3+</sup> : Y<sub>2</sub>O<sub>3</sub> ceramics produced by the method of dry uniaxial pressing of nanopowders was disclosed. It was shown that in ceramic samples the second phase of two types (the intrinsic monoclinic phase of yttria and the impurity phase which is formed due to the stimulation by the impurity cations with the different size from yttrium ion considerably) can be present in respect to the purity of the raw materials and the condition of sintering. It was indicated that the presence of the second impurity phase on the intercrystalline boundaries facilitates the anomalous growth of crystallites.