Physico-Chemical nanomaterials science

Pecularirties of formation (Y,Lu,Sc)2O3:Yb3+ mixed sesquioxide transparent ceramics
Kryzhanovska O.S.1, Parkhomenko S.V.1, Doroshenko A.G1. Baumer V.M.2 , Yavetskiy R.P.1, Bezuglyi V.A.1, Tolmachev А.В.1, Jiang Li3
1Institute for Single Crystals of NAS of Ukraine, Nauky ave., 60, Kharkiv - 61072, Ukraine. E-mail: olekskryzhanovska@gmail.com
2 STC ‘‘Institute for Single Crystals’’, NAS of Ukraine, Nauky ave., 60, Kharkiv - 61072, Ukraine.
3 Shanghai Institute of Ceramics Chinese Academy of Sciences, Dingxi Road, No. 1295, Shanghai - 200050, P.R. China.

Lanthanum oxide is widely used as a sintering additive in the production of high-transparency Y2O3:Yb ceramics [1]. La2O3 activates diffusion processes in ceramics. In addition, the incorporation of lanthanum ions in the Y2O3:Yb structure leads to a broadening of the ytterbium ion absorption lines. However, there is no literature data on the mechanisms of the lanthanum ions entry into the yttrium oxide lattice. Therefore, the study of the phase formation processes in the system Y2O3-La2O3-Yb2O3 at various stages of the synthesis of transparent ceramics is an actual problem. The purpose of this work is to trace the evolution of the phase composition of heavy-doped ceramics (Y0.86La0.09Yb0.05)2O3 during the interactions between yttrium, ytterbium and lanthanum oxides in temperature range 1100-1400°C, corresponding to the processes of La2O3 and Yb2O3 phase dissolution in yttrium oxide, and densification of ceramics also. The high concentration of lanthanum and ytterbium ions makes it possible to determine accurately the change in the concentration of lanthanum-containing and ytterbium-containing phases.
(Y0.86La0.09Yb0.05)2O3 transparent ceramics was obtained by solid-phase sintering. The phase composition of the powder mixtures after annealing at temperatures of 1100, 1200, 1300 and 1400 ° C was studied. It is shown that in the 1200-1300°C range, lanthanum ions enter the crystal structure of Y2O3 and Yb2O3, which is accompanied by a sharp increase in the volume of the corresponding crystal cells and a retard of crystalline grains growth of the corresponding phases. Yb2O3 phase in the Y2O3 matrix is completely dissolved in the range 1300-1400 °C. Complete dissolution of La2O3 in the Y2O3 matrix occurs at temperatures above 1400°C.

1.	Rhodes W.H., Wei G.C., Trickett E.A. Lanthana-doped yttria: a new infrared window material // SPIE. Infrared Opt. Transmit. Mater.– 1986.– 0683.– P. 12-8.