Preparation Of Sc₂O₃ Laser Ceramics With High Transparency

In order to solve the disadvantages of traditional co-precipitation method,such as nonuniform and serious agglomeration,the nano-powder with high purity and good dispersibility was prepared by the parallel precipitation method based on micro-reaction.The Sc₂O₃ transparent ceramic was obtained by vacuum sintering plus hot isostatic pressing sintering.The effects of different alcohol-water ratios（R values）on the phase composition and morphology of nano-powders were investigated.The results showed that the alcohol-water solution as mother salt solvent could effectively improve the dispersibility of powders.The agglomeration of powders was significantly reduced.At the same time,the introduction of alcohol would not change the chemical composition of powders.The precursors with different R values could be completely converted into pure Yb:Sc₂O₃ nano-powders after sintering at 1100°C.When the R value reached 1/5,the dispersibility of powder was the best.The particles were elliptical and the average size was about 50nm.After hot isostatic pressing sintering,the pure phase 10 at%Yb:Sc₂O₃ ceramics was obtained,and the average grain size was about 3μm.The fine and uniformly distributed grains benefited from the highly dispersed and weakly agglomerated nano-powders.The in-line transmittance reached 76.4%and 78.1%at 800 nm and1200 nm,respectively.(Sc_1-xYb_x)₂O₃（x=0,0.02,0.03,0.05,0.07,0.10）and(Sc_0.93Yb_0.07-xLu _x)₂O₃（x=0,0.035,0.049,0.063）transparent ceramics were prepared by solid phase synthesis.The effects of rare earth doping ions(Yb³⁺,Lu³⁺)concentration on the phase structure,microstructure and transmittance of Yb:Sc₂O₃ transparent ceramics were investigated.The results showed that in(Sc_1-xYb_x)₂O₃ system,Yb³⁺replacing Sc³⁺did not affect the cubic phase structure of Sc₂O₃ ceramics.Along with the concentration of Yb³⁺increased,the grain size of Sc₂O₃ ceramics decreased continuously.When x=0.1,the in-line transmittance of 10 at%Yb:Sc₂O₃ ceramics reached 79.4%at 800 nm,and the corresponding smallest grain size was 1.96μm.In(Sc_0.93Yb_0.07-xLu_x)₂O₃ system,（Yb,Lu）³⁺composite doping did not change the phase structure of Sc₂O₃ ceramics,and the impact on the size of ceramic grains was slight.When the doping amount of Lu₂O₃ was 0.35 at%,the transmittance of(Sc_0.93Yb_0.035Lu_0.035)₂O₃ ceramic reached 78.3%at 800 nm.Using Al₂O₃ as a new type of high-efficiency sintering aid,x at%Al₂O₃:(Sc_0.9Yb_0.1)₂O₃（x=0,0.01,0.02,0.03,0.04,0.06,0.08,0.10）transparent ceramics were prepared by solid phase synthesis.The effects of trace Al₂O₃ as sintering aids on the optical properties,morphology and phase composition of Yb:Sc₂O₃ ceramics were analyzed.The results showed that the introduce of trace Al₂O₃ had not effect on the phase structure of Yb:Sc₂O₃ ceramics.With the increasing of Al₂O₃,the ceramic grain size first decreased and then increased,and the in-line transmittance first increased and then decreased.It was presumed that this was caused by liquid phase sintering of Al₂O₃.When the amount of Al₂O₃ reached 0.02 at%,The grain size of 10at%Yb:Sc₂O₃ ceramics was 2.3μm and the in-line transmittance reached 79%and80%at 800 nm and 1200 nm,respectively.In addition,when the annealing temperature reached 1200°C,the transmittance of all ceramic samples hardly changed.