THE STRUCTURE AND PROPERTIES OF Er2O3 AND Yb2O3 BASED CERAMIC MATERIALS, SINTERED UNDER HIGH PRESSURE

The aim of the work was to obtain high-density optically transparent ceramic samples by sintering cubic modification Er2O3 and Yb2O3 oxides micropowders at the pressure of 7 GPa and the heating current power of 0.6–1.0 kW, which was demonstrated. Non-monotonic dependence of the density on the heating current power has been established. The maximum density values of 9.2 g/cm3 (Er2O3) and 9.8 g/cm3 (Yb2O3) were achieved at the power of 0.8 and 0.9 kW, respectively. During sintering, the cubic phase partially transforms into the monoclinic phase, which is preserved in the obtained samples. The ceramics compaction process is accompanied by grain growth, more intense in erbium oxide samples. At sintering Yb2O3 micro-powder with particle size of 7.5–15 μm with the lowest heating current power value of 0.6 kW a microstructure similar to the nanocrystalline with the grain size of 90–200 nm, which contributes to higher transparency in the infrared wavelength range. Er2O3 samples have a discontinuous transmission spectrum, while Yb2O3 samples – a continuous one in the wavelength range of 400–850 nm. The maximum transmission values for ceramic samples are 29% at a wavelength of 750 nm, 52% at 849 nm for Er2O3 and 72% at 830 nm for Yb2O3.