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This thesis is an overview of Nd: YAG nanopowder and transparent ceramics development and preparation methods , and describes the development and application of supercritical drying technology . This paper as the raw material of aluminum nitrate , yttrium nitrate , neodymium nitrate , ammonium bicarbonate and urea as the precipitating agent , chemical precipitation combined with CO2 supercritical fluid drying technology to synthesize a series of neodymium - doped yttrium aluminum garnet precursor powder , and calcined at different temperatures of samples of Nd: YAG . XRD, FT-IR, TG / DTA, SEM, BET and fluorescence spectrophotometer testing means to characterize the precursor and calcined product . The results show that using ammonium bicarbonate co-precipitation method combined with CO2 supercritical drying prepared 1% Nd : YAG precursor 271.64m2 · g - 1 , specific surface area , XRD results showed that the precursor for crystalline calcined at 1100 ° C in air for 2h after YAG crystal phase , while inclusion Y2O3 and YAM phase pure YAG remains after the 1400 ° C calcined 2h . Urea homogeneous precipitation precursor prepared as amorphous hydroxide and carbonate mixture , conventional drying method , the precursor is smaller than the surface area , and the occurrence of serious reunion 1000 ° C calcined pure Nd: YAG, particle size The uneven distribution, poor dispersibility , agglomeration . Comparison with the conventional drying method results , CO2 supercritical drying significantly improved serious agglomeration problems occurred in the conventional drying , the precursor powder having a good dispersibility , a high specific surface area and the sintering activity , calcination at 800 ° C directly after the formation of pure YAG the phase does not appear, the intermediate phase , 000 ° C after calcination powder was able to maintain a good dispersibility , the particles were of spherical shape , size distribution between 35-45nm . Crystallization product are the precursor of the different amount of neodymium doped YAG phase , does not appear to mesophase. The lattice parameters increase in the amount of neodymium doped larger 2E value becomes smaller with the increase in the amount of the neodymium -doped . Fluorescence spectra show that the Nd : YAG powders fluorescence emission and excitation spectrum relative luminous intensity with calcination temperature and enhance the trend was increased and then decreased with the increase in the amount of neodymium -doped doping amount The luminous intensity of 0.8 % maximum .
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