A NEW PLASMA METHOD OF SYNTHESIZING AEROSOL-PARTICLES

A new experimental method of synthesizing aerosol particles is demonst rated. A nonthermal plasma is used to sputter a solid target by energe tic ion impact. Sputtered atoms nucleate in the gas phase to form part icles, which the plasma levitates particles during several hours of op eration. Particle growth can take place at room temperature. The plasm a is formed in a vacuum vessel by a pair of parallel electrodes that a re powered with a radio-frequency high voltage. Scanning electron micr ographs reveal the particle morphology. Particles initially grow with a spherical shape, and their size can be selected by terminating the d ischarge after they have grown to the desired diameter. By altering th e plasma parameters such as gas pressure and voltage, and by allowing particles to grow for a longer period of time, they can coagulate into string-like or fractal-like conglomerates. Copyright (C) 1996 Elsevie r Science Ltd