ABSTRACT
Atmospheric pressure plasma jets operate at ambient pressure without the need for complex equipment to reach low pressures. Plasmas can be classified also on the basis of temperature, that is, thermal equilibrium. In non-thermal plasmas, the temperatures of the electrons and the ions are in a thermal non-equilibrium. The common feature of all the plasmas is that they use vaporized chemical compounds or gaseous precursors. In a typical plasma process, the precursor molecules are introduced and ionized in a chamber with selected concentrations. Thermal plasmas are produced at high pressure using direct or alternating current or radio frequency or microwave sources. Due to the high plasma temperature, torches are used to destroy toxic and dangerous substances or, as in the case of the plasma spray, to produce thick coatings. The utility of plasma processes arises from the significant intensification of chemical processes at the substrate surface, and often promotion of chemical reactions impossible in conventional chemistry.
