This study systematically compares the surface polishing performance and finishing results of the following two different electrolytic plasma polishing technologies on stainless steel AISI 316L: (i) plasma electrolytic polishing (PEP) and (ii) plasma electrolytic polishing jet (PEP-Jet). The two techniques are compared against an industrial standard polishing method, electropolishing (EP). For comparable energy density consumption, the samples treated with the PEP-Jet technique showed the highest removal rate, up to three times less than the initial roughness, resulting in the highest surface roughness reduction from Sa = 249 nm to Sa = 81 nm. Microstructure characterization of samples treated using PEP-Jet also showed well-defined crystalline grain boundaries with a distinct appearance of predominantly inter-crystalline structures within individual grains, which is uncommon with EP techniques. The surfaces treated using PEP-Jet exhibited the lowest corrosion rate of $6.79\times {10}^{-5}$ mm/year, and no signs of areal corrosion were detected in the performed corrosion tests in contrast with the other samples and their respective treatments. The comparative analysis revealed that the high ionic current delivered by the electrolyte jet flow in the PEP-Jet process effectively stabilizes the plasma at the contact zone, thereby enhancing the plasma polishing of austenitic stainless steel samples. The efficacy of this method has been demonstrated in terms of reducing energy consumption and enhancing corrosion resistance in comparison with (PEP) and (EP) as state-of-the-art processes in corrosive environments of high-alloyed steel.

This study investigates electrolyte jet processing of metals by plasma polishing, focusing on the polishing regimes and their governing flow dynamics, which result in different current density distributions and, consequently, different plasma polishing regimes. Experimental investigations performed at 350 V using a fixed-diameter electrolyte jet included localized current measurements and surface topography characterization, while finite element method (FEM) simulations were used to evaluate four plasma vapor–gas envelope (VGE) geometries. The experimental results revealed two distinct polishing regimes: a contact zone coinciding with the nozzle diameter, where the highest local cur-rent density reached 10.8 mA/mm² and produced a maximum material removal rate of 1.17 µm/s, and a surrounding electrolyte splash zone extending to approximately twice the nozzle diameter, where the local current density progressively decreased to 2.6 mA/mm², corresponding to a minimum material removal rate of 0.16 µm/s. Unlike previous, studies the numerical simulations showed that a constant plasma vapor–gas envelope thickness of 15.8 µm provided the closest agreement with the experimentally measured polishing profile. Based on the combined experimental and numerical results, the contact zone is interpreted as a plasma-dominated region characterized by high current density, whereas the splash zone is interpreted as a transient plasma regime in which electrochemical polishing increasingly dominates as current density decreases. This study improves the understanding of plasma electrolyte polishing (PEP), which involves both plasma-assisted and electrochemical material-removal mechanisms. The results provide guidance for im-proving surface quality and process efficiency in electrolyte-jet PEP of stainless steel.