Abstract:Nanocrystalline silver particles were produced by hydrogen reduction of silver nitrate aerosol droplets formed by high frequency ultrasonic generator. The dependences of the particle size, morphology and crystallite size on the precursor concentration and the reaction temperature were investigated. Ultrasonic spray pyrolysis process was combined with hydrogen reduction to research the effects on the silver particle production. Nanocrystalline silver particles including slight oxide structure were prepared at temperature as low as 200 °C from silver nitrate under hydrogen atmosphere. X-ray diffraction (XRD) studies showed that pure silver particles were obtained above 200 °C reaction temperature. The crystallite sizes of the samples ranged from 29 to 47 nm. The results indicate that the crystallite sizes hardly ever depended on the reaction temperature. Crystallites slightly enlarged by increasing precursor concentration. SEM observations showed that particles were obtained in spherical morphology with particle sizes between 210 and 525 nm. Reaction temperature and precursor concentration strongly influenced the particle size.

Key words: silver particles; nanocrystalline materials; aerosol process; hydrogen reduction