Abstract: Yb:YAG transparent ceramic nano-powder was prepared by chemical co-precipitation method，with ammonium bicarbonate or ammonia as the precipitant.The morphology and phase structure of Yb:YAG nano-powder were characterized by scanning electron microscopy（SEM） and X-ray diffraction（XRD）.Results showed that pure YAG phase nano-powder was obtained by calcining the precursors prepared by using ammonium bicarbonate as the precipitant at 1 200 ℃.However，YAM（Y4Al2O9） phase was found in the XRD patterns of the Yb:YAG powders synthesized by co-precipitation method using ammonia as precipitant at 1 200 ℃.Well dispersive，pure YAG nano-powders with the particle size in the range of 100~250 nm were obtained by calcining the precursor prepared by using ammonium bicarbonate as the precipitant and the optimum concentration ratio of NH4HCO3 to Al3+ was 10∶1.

Key words: Yb:YAG, co-precipitation, precipitant, nanometer powders