Effect Of Plasma Enhanced Electrochemical Polishing On Surface State Of Austenitic Stanless Steel

Aiming at the existing common polishing processes(mechanical polishing,chemical polishing and electrolytic polishing),such as low polishing efficiency,limited original surface of disposable materials,poor polishing quality,difficulty in dealing with complex special-shaped structural parts and environmentally unfriendly solution,in this paper,based on plasma enhanced electrochemical polishing technology and 316L austenitic stainless steel.Studying the effects of degree,voltage,frequency and pulse width on the rate of plasma enhanced electrochemical polishing and ensuring the optimum polishing parameters.Secondly,the effects of mechanical polishing,electrolytic polishing and plasma enhanced electrochemical polishing on the surface state of materials were compared and analyzed by characterizing the dynamic curve of surface roughness change,surface morphology,elements,phase,grain,residual stress,hardness and corrosion resistance.Finally,Dissusing and analysing the mechanism of plasma enhanced electrochemical polishing.The results show that increasing the concentration of electrolyte properly(<3%)is beneficial to enhancing the conductivity of the solution,accelerating the rate of bubble formation and collapse,which makes the polishing rate faster;increasing the voltage(>300V)will lead to more contact times between the anode workpiece and the electrolyte,decrease the temperature of the solution,collapse before the bubbles develop,and slow down the polishing rate;the appropriate frequency(25kHz)and the pulse width(15)will obtained the optimum bubble formation and collapse rate,which maximizes the polishing rate.It is found that plasma enhanced electrochemical polishing can polish the samples with high initial roughness and reduce the initial roughness to a minimum accuracy.The polishing speed is fast and can reach 100 nm/min in the early stage of polishing.The polished material has good surface quality,no scratches,sub-crevice cracks and corrosion pits,no obvious changes in surface elements,no new phase formation,and grain refinement to a certain extent.It canThe mechanism of plasma enhanced electrochemical polishing is to place the workpiece in the electrolyte and form a slurry isolation layer on the surface of the anode workpiece by applying a certain voltage(>300 V).A large number of oxygen plasma are formed by gas bridge breakdown due to the action of high voltage and strong electric field.These high density oxygen plasma will react with the metal ions of the anode to form an oxide sparsening layer.High concentration of water vapor and oxygen bubbles will produce a tangential cavitation force when they collapse.The oxide layer on the surface of the workpiece will be removed by the high frequency bubble cavitation force,Finally,the polishing effect is achieved.