Effect of reactive plasma-forming gases on plasma spray operating conditions

Modern plasma spray coating technology allows the use of high-enthalpy plasma-forming reactive gases. Plasma gun thermal efficiency, which defines spray output and coating quality, can be increased. Unlike the argon plasma jet, the CH sub 4 -CO sub 2 plasma jet oxidation/reduction potential is adjustable and has an enthalpy that is seven to ten times higher. Argon-based gas mixtures are most appropriate for spraying materials that exhibit a high chemical affinity for reactive gases. Otherwise, mixtures of CH sub 4 and CO sub 2 are preferable because of higher enthalpy, lower cost, and the possibility of improving the working conditions of the plasma gun electrodes. A universal plasma gun has been developed that uses various plasma-forming gases. The choice of gas depends on the specific plasma spray technology requirements.