the saturation concentration in order to prevent precipitation of solids before removal of the liquid solvent 2 the concentration of the droplets in the aerosol must be sufficiently low so that it is below the concentration where collisions and subsequent coalescence of the droplets results in a 10 reduction in droplet concentration causing significant broadening of size distribution though it is essential to operate under the saturation point of the copper containing compound the concentration is not otherwise critical in the operation of the process much lower concentrations of the copper containing compound can be used however it will ordinarily be preferred to use higher concentrations to maximize the mass of particles that can be made per unit of time the concentration will determine the resulting size of the copper oxide particle the higher the concentration of copper containing compounds in the droplet the more mass in the droplet and the subsequent increase in the size of the particle in addition particle size is an approximate function of the cube root of the concentration if a greater change in particle size is needed a different aerosol generator must be used any conventional apparatus for droplet generation may be used such as nebulizers collision nebulizers ultrasonic nebulizers vibrating orifice aerosol generators centrifugal atomizers two fluid atomizers electrospray atomizers and the like the particle size distribution of the powder is a direct function of the distribution of the droplet sizes generated therefore the overall particle size distribution is dependent on the generator chosen for the process virtually any carrier gas which is inert with respect to the solvent for the copper containing compound and with respect to the compounds themselves and the copper i oxide powder may be used examples of suitable carrier gases are nitrogen argon helium and the.