Plasma Electrolytic Polishing Process: Mechanism and Characteristics

Electrolytic polishing (EP) which is commonly used to remove burrs and machining marks from the surface of parts, is not suitable for finishing alloys as each component has its distinct dissolution rate. Another limitation is the high processing time. In recent decades, the research and applications of plasma electrolytic polishing (PeP) have increased, making it suitable for processing of alloys faster than EP. In this work, we present an experimental study on PeP wherein we investigate the influence of applied potential and processing time on surface roughness. For this, cubical SS304 substrates having dimensions as 9.5 mm × 9.5 mm × 10 mm and initial roughness Ra of 1.48 μm were finished using a 1.5% w/v sodium nitrate (NaNO3) aqueous solution. Experimental results suggest that with an increase in applied potential, the Ra value decreases for a specific processing time. Also, for a specific value of applied potential, the value of Ra decreases, and the surface becomes glossy as the processing time increases. Finally, a minimum Ra of 0.225 μm is achieved at an applied potential of 350 V and a processing time of 150 s.