Material removal model for describing the plasma discharge effect in magnetic-electrolytic plasma polishing

Magnetic-electrolytic plasma polishing is a method employed for achieving metal surface planarization through the synergistic effects of electrochemical dissolution and plasma discharge. While numerous studies have focused on elucidating the electrochemical reaction mechanism, there exists a notable gap in understanding and modeling the impact of plasma discharge on material removal. Consequently, this paper introduces a novel plasma discharge kinetic model designed to elucidate the discharge behavior within electrolytic plasma. The innovation lies in the representation of electron collisions in plasma discharges using the Boltzmann kinematic equation. This enables the derivation of the physical dynamics of electrons, including their momentum distribution functions during ionization collisions. Furthermore, the paper incorporates an instantaneous high-temperature melting mechanism resulting from plasma discharge into the surface material removal equation. Corresponding boundary conditions are established for numerical simulations. To validate the proposed model, magnetic-electrolytic plasma polishing experiments are conducted, varying the magnetic field intensities, with TA1 titanium alloy as the test material. Simulation results reveal that the magnetic field enhances the spatial electric field created by the uneven distribution of ion electrons. This enhancement expedites the plasma discharge process towards the anode, generating interference currents that counterbalance the required material removal current. Experimental data is provided to corroborate the model, consistently demonstrating a positive correlation between circuit current and material removal rate. This research underscores the rationality and reliability of the material removal model for plasma discharge, providing a fundamental understanding of electromagnetic plasma polishing.