SIZE MEASUREMENT OF FINE POWDERS USING THE DIFFERENTIAL MOBILITY ANALYZER - APPLICATION OF BOILING METHOD FOR AEROSOL GENERATION

A method for aerosol generation, termed the ''boiling method,'' was pr eviously developed to effectively disperse in air a powder consisting of coagulated submicron particles into their primary particles. Here, in order to apply the boiling method to the particle size measurement of a fine powder, the method is combined with a particle size measurem ent system comprising a differential mobility analyzer (DMA) and a con densation nucleus counter (CNC). To avoid the presence of residue part icles after evaporation, Fluorinert (perfluorocarbon) has been chosen as the boiling liquid medium. The particle size distributions measured for several kinds of powders are in good agreement with the results o btained by electron microscope and centrifugal sedimentation method. T he method is found to be useful for the particle sizing of fine powder s in air. Moreover, the method can also be successfully used as a cont inuous generator of monodisperse aerosol particles having a high conce ntration.