The influence of vapor–gaseous envelope behavior on plasma electrolytic coating removal

This paper discusses the study of the behavior of the vapor–gaseous envelope during the plasma electrolytic removal of the titanium nitride coating from stainless steel hardware. A model of the process which explains the distribution of the full coating removal area along the sample has been developed. It is based on the behaviour of the film, bubble and transient types of boiling. It has been shown that an unstable oscillating vapor–gaseous envelope causes intense surface oxidation, whereas the bubble type of boiling provides the best conditions for steel polishing. A combination of these modes leads to coating removal. The obtained data are correlated with the characteristics of the DC and AC components of the current in the system. The results can be used for developing optimal modes for the plasma electrolytic treatment of steel hardware. The parameters of the DC and AC components of the current provide necessary information for creating a real-time feedback control system for the process.