Yb:Lu_3Al_5O_(12)(Yb:LuAG) nano powders were synthesized with the co-precipitation method from cation(Lu^(3+),Yb^(3+),Al^(3+)) solution of different concentrations using NH_4HCO_3 as the precipitant.The influence of cation concentration on the morphology and purity of the calcined powders was studied.Contrary to the conventional suggestion that recommends thin solution to obtain loosely agglomerated nano powders,results showed that thin cation(Lu+Yb+Al) concentration≤0.08 mol/L led to formation of Al_2O_3 and LuAP impurities in the obtained nano powders.By means of Tg/(DTA),X-ray diffraction(XRD),scanning electron microscopy(SEM),the cause was revealed to be re-dissolution of Lu at high pH value that resulted from the decomposition of NH_4HCO_3.(Lu+Yb+Al) concentration of ~0.24 mol/L was recommended to achieve pure Yb:LuAG nano powders.Transparent Yb:LuAG ceramics were fabricated with the prepared Yb:LuA G nano powders.The transmittance around 800 nm was 77.5%.
Yb:Sc2O3 transparent ceramics were fabricated by solid-state reaction and vacuum sintering method.CaO was added as sinteringaids by a high energy ball milling.Transparent nearly-fully dense samples were obtained after 1840 oC sintering.Using transmitted-light microscopewe get the grain sizes are more than 100 μm.Using spectrophotometer we get the absorption coefficient centered at 975 nm was 2.65 cm-1.The phosphorescence spectra showed that the line-widths(FWHM) at 975 and 1041 nm were about 4 and 10 nm and the lifetime of Yb ionsin Sc2O3 transparent ceramics was about 883 μs.According to the absorption and fluorescence band centers of Yb:Sc2O3 transparent ceramics,the level scheme of Yb3+ ions in Sc2O3 ceramics could be gotten.
