Localised corrosion attacks and oxide growth on copper in phosphate-buffered saline

• Published in: Materials characterization Vol. 158; p. 109985
• Main Authors: Luo, Jiaqi, Hein, Christina, Pierson, Jean-François, Mücklich, Frank
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.12.2019; Elsevier
• Subjects: Copper; Corrosion; Cuprous oxide; E. coli; Engineering Sciences; Orientation; PBS; PBS; Corrosion; Copper; Orientation; Cuprous oxide; E. coli
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2019.109985

Phosphate-buffered saline (PBS) is a buffer commonly used in antibacterial surface research. However, how copper surface varies in the buffer, in terms of corrosion attacks and oxide growth, is not yet fully recognised. In this study, PBS was applied as droplet on two types of copper surface: ground and electropolished. By scanning electron microscope (SEM), the similarities of their corrosion sites were compared, revealing the initiation of intergranular attack and orientation-dependent crystallographic etching. High resolution grazing incidence X-ray diffractometer (GIXRD), optical microscope (OM), Raman spectroscopy, and electron backscatter diffraction (EBSD) together provided detailed description of the epitaxial growth of cuprous oxide (Cu2O) on electropolished copper. The amount of copper ions released from two types of surface were determined by inductively coupled plasma mass spectrometry (ICP-MS). By introducing E. coli into PBS, the inhibition of Cu2O growth on electropolished coupon was observed. However, bacteria were found to hardly alter the corrosion mechanisms or the distribution of corrosion sites. [Display omitted] •Backscatter electron images revealed corrosion sites on copper beneath oxide.•Intergranular and localised galvanic corrosion were found on electropolished copper.•Crystallographic etching on grains was found to be orientation-dependent.•Growth of Cu2O on electropolished copper was an epitaxial re-deposition process.•Presence of E. coli did not change the corrosion attacks but the Cu2O formation.