Abstract

The electrochemical behaviour of copper in borate buffers containing KSCN is studied by potentiostatic and potentiodynamic techniques complemented with scanning electron microscopy and EDAX. The voltammetric response can be divided into three regions. Region I is related to the formation of a Cu(SCN) ad monolayer followed by a porous tridimensional growth of CuSCN(s). A complex oxide layer containing a Cu(I) inner and a Cu(II) outer layer is formed under the CuSCN layer leading to metal passivation. At this stage of the process soluble Cu(I) and Cu(II) species are detected. Region II corresponds to the onset of Cu passivity through the formation of a complex film. The passive region extends up to a certain critical value (breakdown potential) associated with the localized corrosion of base Cu (region III). The breakdown potential decreases linearly as the KSCN concentration increases. The localized corrosion process is apparently related to the nucleation and growth of an unstable Cu(SCN) 2 layer in equilibrium with Cu(SCN) − 3(I). A reaction pathway is presented to account for the overall electrochemical behaviour of Cu in borate buffers containing KSCN.

Highlights

  • Copper, as other metals, is used in many technical applications

  • These results suggest that copper oxide electroformation is hindered in the presence of KSCN, but the electroreduction of Cu(1)

  • The breakdown potential (Es) is estimated from voltammograms run at low sweep rates (0.002 and 0.0002 Vs-i) in the borax buffer containing different concentrations of KSCN (Fig. 2)

Read more

Summary

AND PITTING PROCESSES

Instituto de Investigaciones Fisicoqufmicas T&rices y Aplicadas (INIFTA), Casilla de Correo 16,Sucursal, (1900) La Plats, Argentina (Received 20 August 1985). Region I is related to the formation of a CU(SCN)~ monolayer followed by a porous tridimensional growth of CuSCN(s). A complex oxide layer containing a Cu(I) inner and a Cu(II) outer layer is formed under the CuSCN layer leading to metal passivation. At this stage of the process soluble Cu(1) and Cu(II) species are detected. Region II corresponds to the onset of Cu passivity through the formation of a complex film. The breakdown potential decreases linearly as the KSCN concentration increases.The localized corrosion process is apparently related to the nucleation and growth of an unstableCu(SCN), layer in equilibrium with Cu(SCNK(I). A reaction oathwav is eresented to aceeunt for the overall electrochemical behaviour of Cu in borate bu%ers containing KSCG. _

INTRODUCTION
The initial single triangular potential sweep at
The inspection of the voltammogram resulting when
Current transients under a constant potential step
SEM patterns and EDAX data
DISCUSSION
Reactions related to region I
Reactions related to region II
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.