The effect of ZrO2 concentration on the optical properties of Y2O3 transparent ceramics

Y?O? ceramics for different applications. However, the process of obtaining this material is challenging due to the high melting point of Y2O3, and, therefore, sintering aids are used to reduce the sintering temperature and promote densification during the process [1]. For the presented work ZrO2 was chosen, since it is one of the common sintering aids for producing Y2O3 ceramics [2]. The aim of the study is to establish the optimal concentration of ZrO? for obtaining transparent Y?O? ceramics. The concentration of ZrO? varied in the range of 0-11 mol%. Transparent optical ceramics Y?O?:Zr?? were obtained from a stoichiometric mixture of powders by uniaxial pressing followed by CIP (cold isostatic pressing) and vacuum sintering at 1735°C for 22 hours. The dependence of the optical characteristics of transparent Y?O? ceramics on the concentration of ZrO? was investigated. It was established that 7 mol% is the optimal concentration that allows obtaining yttrium ceramics of the highest optical quality. This sample is characterized by full densification (100% of the theoretical value), homogeneous microstructure without defects, such as pores or secondary phases, and mean grain size of about 4.8 ?m. The optical transmittance of this sample reached 80.2% at 1100 nm. When no sintering aid was used, significant grain growth was observed (about 14 ?m) and the formation of almost opaque ceramics with a transmittance of 7.2% at 1100 nm. An increase in the concentration of ZrO2 up to 7 mol% leads to an increase in optical transmittance. With the subsequent addition of a sintering aid, the optical properties of ceramics deteriorate slightly. At the same time, it is worth noting that the presence of secondary phases is not observed even at 11 mol% of ZrO2. This indicates that for the studied composition range, a solid solution of ZrO2 in Y2O3 is obtained without reaching the solubility limit. References 1. B. Ahmadi, S.R. Reza, M. Ahsanzadeh-Vadeqani,et al, Ceram. Int., 2016, 42, 17081-17088. 2. X. Hou, S. Zhou, Y. Li, et al, Opt. Mater. (Amst.), 2010, 32, 920-923.