Abstract: The silver-silica composite grains with different structures were prepared by Sol-gel technology. The formation mechanism was analyzed, the structures of composite grains were characterized by transmission electron microscope (TEM), scan electron microscope (SEM), X-ray diffraction (XRD),Fourier transform infrared spectrometer(FT-IR) and ultraviolet-visible spectroscopy(UV-Vis). The results indicated that the average size of composite grains(290 nm) was homogeneous and the form was similar to sphericity; and Ag grains(4 nm)which were linked on the surface of silica were also homogeneous distribution. In addition, the distribution of Ag grains on the surface of silica were affected by silane coupling agent KH-550, the network system of silica Si-O-Si was affected definitely by silane coupling agent KH-550 , which controled effectively the cluster degree of composite grains.

Key words: Ag;silica;silane coupling agent;composite nanoparticles