In Situ Studies of the Effect of CO[sub 2] on the Initial NaCl-Induced Atmospheric Corrosion of Copper

Abstract

The effect of carbon dioxide ͑CO 2 ͒ on the NaCl-induced atmospheric corrosion of copper was studied using in situ Fourier transform infrared microspectroscopy, in situ scanning Kelvin probe, and scanning electron microscopy/energy-dispersive analysis by X-ray. The copper surface was contaminated with a single NaCl particle and then exposed to 80 ± 2% relative humidity clean humidified air with two concentrations of CO 2 ͑Ͻ5 and 350 ppm͒. After formation of an electrolyte droplet secondary spreading of electrolyte from the peripherical parts of the droplet was observed. The secondary spreading effect, which was much larger at Ͻ5 ppm CO 2 than at 350 ppm, was a consequence of the formation of a galvanic element between a local cathode outside the edge of the droplet and an anode in the droplet. This lead to alkaline conditions in the secondary spreading area and transport of Na + ions to the local cathode. The large secondary spreading at low CO 2 concentration was possible due to lowering of the surface tension of the electrolyte/metal oxide interface at the peripheral parts of the droplet. Carbonate formation lowered the pH when the CO 2 concentration was 350 ppm and resulted in a decrease of the pH and inhibition of the secondary spreading.

Effect of Relative Humidity on Corrosion of Steel under Sea Salt Aerosol Proxies

“…It should be noted that development of sodium-rich alkaline films emanating from aqueous NaCl droplets under which corrosion is taking place, termed secondary spreading, has been reported by a numerous researchers for a variety of alloy systems above the DRH, including mild steel. 12,40,57,58 To our knowledge, this is the first reported instance of such phenomenon occurring substantially below the DRH.…”

Multidimensional electrochemical imaging in materials science

“…In the past decade many KFM studies have also been conducted on a broad range of topics in corrosion science, including research on the corrosion behavior of steel [136][137][138][139][140][141][142][143][144], Al [143], Cu [145][146][147][148], Zn [143,144,[149][150][151][152], alloys based on Al-Mg [153][154][155][156][157][158][159][160][161][162][163][164] and Ti [165], on corrosion protection with rare-earth elements [166] and other inhibitors [167][168][169][170], the effect of conversion coatings [171][172][173][174][175][176], and the effects of heat treatment on material properties [177][178][179]. Yamawaki et al …”

Identification of Corrosion Products on Fe and Cu Metals using Spectroscopic Methods

“…Chloride ions present in many environments are very aggressive agent which can cause extensive corrosion of many materials [2,[5][6][7]. Chloride containing corrosion products are then very often detected on iron and copper objects [5][6][7][8].…”

“…Chloride containing corrosion products are then very often detected on iron and copper objects [5][6][7][8].…”

“…acids, bases and salts), thus many researchers have been involved in studies of the corrosion process in such media [5][6][7][8]. In the literature, the identification of the corrosion products is provided mainly by methods such as X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy combined with an electron microprobe (SEM-EDS), less frequently infrared spectroscopy (IR) and the Raman spectroscopy (RS) [9][10][11][12].…”