Study On The Preparation And Characteristics Of Yb³⁺: Y₂O₃ Ultrafine Powders For Transparent Ceramics

Yb³⁺:Y₂O₃ ceramics is a new candidate for high power laser. Obtaining ultrafine powders with uniform size and good dispersion are the prerequisite for preparing transparent Yb³⁺:Y₂O₃ ceramics with high optical quality. In this thesis the liquid phase co-deposited method and LCS method were adopted to prepare the Yb³⁺:Y₂O₃ ultrafine powders.XRD, TG-DTA, TEM, FT-IR and the fluorescence spectra analysis were employed to characterize the Yb³⁺:Y₂O₃ ultrafine powders. The influences of seven factors, including initial pH value , anti-aggregative agent, reaction temperature, holding time, Yb ion content on the morphology, size and property of the powders were systematically studied. The agglomeration phenomenon of the powders prepared by the co-precipitation method was analyzed. The influences of ignition temperature, fuel content and calcination temperature on the characteristics of the powders were investigated for the LCS method.The particle diameters of Yb³⁺:Y₂O₃ ultrafine powders synthesized by the co-precipitation method were about 100 - 200nm. The optimum technology parameters were obtained as followings. The pH value is between 8 and 9. The titration velocity should be less than 2ml per minute. Surfactant (NH₄)₂SO₄ was 5mol% to Y(NO₃)₃. The calcining temperature and time of the powders were 1100℃and 4 hours, Yb content is 3at.%. The luminescence spectrum is consisted of three peaks at 976nm, 1030nm and 1075nm respectively under excitation of 514nm which is attributed to transition of ²F_5/2→²F_7/2 of Yb³⁺. Among the three peaks 1030nm showed the strongest intensity.. Absolute ethyl alcohol decreased the conglobation phenomenon of the ultrafine powders. The particle diameters of Yb³⁺:Y₂O₃ ultrafine powders prepared by using the LCS method were about 15-30nm. The optimum technology parameters of LCS were that the value of nitrate : urea was 3:1, and the ignition temperature was about 600℃.