Nanometer silver grain growth and particle's aggregation were effectively prohibited by polyvinyl pirrolidon (PVP) when the silver powder prepared from silver nitride solution reduced by hydrazine hydrate. On the base of ultraviolet spectra and FTIR spectra measurement, PVP protecting mechanisms proposed in this paper were that, first, the coordinative bonds were formed between PVP and silver ions; secondly, a large number of silver embryos were generated during the initial reaction period due to the coordinative bonds formation; and finally, silver embryos and the PVP steric effects were responsible for the inhibited grain growth and the grain aggregation of silver particles.

Key words: ULTRAVIOLET SPECTROPHOTOMETRY, SILVER, INFRARED SPECTROPHOTOMETRY, REDUCTION, POLYVINYLPYRROLIDONE, NANOPHASE MATERIALS