Abstract: A new kind of light-sensitive CaWO₄ core/AgX shell microcrystal emulsion was first synthesized. The outer structures of CaWO₄ core/AgX shell microcrystal emulsion were observed by TEM and SEM, and the photographic properties of the emulsions were tested with X-ray and white light exposure. The results show that photographic property of the emulsion is obviously affected by AgNO₃ displacement percentage, time of KBr displacement and pBr value in displacement process. The thickness of AgX shell on the CaWO₄ core is about 10-15% of the microcrystal diameter. Since CaWO₄ core can absorb X-ray to emit fluorescence to expose the AgX shelled on the surface of CaWO₄ core from internal direction, therefore, the sensitivity of these heterophase microcrystals, comparing with the common cubic AgBr emulsion in the same condition under X-ray and white light exposure, is increased, and is ten and sixteen times higher than that of cubic AgBr emulsion. In a word ,these results show that CaWO₄ core/AgX shell microcrystal emulsion obviously has overwhelmingly advantages over common AgBr emulsion,can largely save valuable Ag, and is a promising information-recording material.

Key words: CaWO₄, nonsilver core/silver halide shell microcrystal, light-sensitive microcrystal