Electrochemical Reduction of Industrial Baths Used for Electropolishing of Stainless Steel

Abstract

Long-term exploitation of industrial electropolishing baths may contribute to the emergence of surface defects and may limit the range of applicable current densities. Due to this, extending the time of use of industrial baths is a major challenge. The application of electrochemical reduction in the process of reduction industrial baths enabled to reduce its contamination and, as a result, to enhance the surface quality of electropolished samples of grade 304 stainless steel. The contamination influence of the electropolishing bath on such parameters of the electropolished samples as roughness, gloss, mass reduction, and corrosion resistance was compared. The conducted tests included reduction of the contaminated industrial bath with use of cathodic reduction and monitoring of bath contamination with use of emission spectrometry ICP-OES. Potentiodynamic tests in 0.5 M chlorine environment with the aim to determine the influence of electrochemical reduction of the plating bath on surface resistance demonstrated that the pitting corrosion resistance of samples electropolished in a bath after reduction was reduced by approximately 0.1 V in comparison with samples electropolished before reduction. The calculations conducted for 24 corrosion resistance measurements demonstrated that differences between the results were significant. Bath reduction leads to improved roughness and gloss, even by approximately 500 GU (gloss units). At the same time, mass reduction decreases even by 13% in comparison with the process conducted in the bath before reduction. This may have a positive influence by slowing down the bath contamination process and, as a result, it reduces negative environmental impact. Another argument that supports the reduction of industrial baths is slowing down the process of cathode contamination during the electropolishing process. In industrial conditions, this may extend the possibility to conduct the process without the need for cathode reduction or replacement.

Electropolishing of Stainless Steel in Laboratory and Industrial Scale

“…The aspect that requires broader verification is the influence of the changing contamination of process baths on the results of the electropolishing process that may be obtained [17,18]. It is essential to determine the threshold level of process bath contamination, up to which the bath may be used, so as to reconcile the satisfying results of electropolishing, the viability of the process and the lowest possible negative environmental impact.…”

Evaluation of Canal Transportation and Centering Ability of Curved Canal Prepared by Two Rotary Systems

“…This asymmetrical cutting profile strengthens the instrument's snake-like flow through the canal while maintaining the canal's original shape. In addition to electro polishing and flexibility, this design can result in improved apical advancement with less transportation (27) . For Wave One Gold; this result is possible for a variety of reasons, one of which is the reciprocation motion which allows for the preservation of the canal's original form in curved roots during instrumentation (28) .…”

Electrochemical Polishing of Austenitic Stainless Steels

“…This is the case when the surface is shiny but not smooth. In Reference [101], defects were presented such electropolishing streaks (oxygen formation and movement). After the electropolishing process, the surface may contain certain defects, including those resulting from long-term use of electrolyte, improper current density, or local overheating of the electrolyte.…”

“…About the right course for the proper conduct of the electropolishing process and other electrochemical processes, decisive is the value of the electrode potential, and the process parameters must be selected so that the anode potential has the desired value. Therefore, for large-size In Reference [101], defects were presented such electropolishing streaks (oxygen formation and movement). After the electropolishing process, the surface may contain certain defects, including those resulting from long-term use of electrolyte, improper current density, or local overheating of the electrolyte.…”