Formation of primary particles in welding fume

The formation of primary particles in the welding fume with regard to gas phase ionization is studied. It is shown that the classical theory is applicable only to the initial moment of condensation of the metals' vapors. The fast coagulation of nuclei leads to the formation of droplets which can unrestrictedly grow and get charged. The subsequent nucleation and growth of the primary particles take place in the charged gas environment with the intensive interphase exchange of the charges and energy. It is shown that the increase of the coagulated droplets' charge leads to the shift of the nucleation in the high-temperature range and to the increase of the primary particles sizes.

► The new theory of nucleation an growth of primary particles is proposed.
► This theory takes into account interaction of nuclei with the charged environment.
► There is displacement of the area of fume formation in the high-temperature range.
► There is increase of nuclei and primary particles radii with increase of gas charge.
► UV-radiation of arc decreases the gas charge and the nuclei and particles radii.