The Atmospheric Corrosion of Zinc in the Presence of NaCl The Influence of Carbon Dioxide and Temperature

Abstract

The atmospheric corrosion of zinc has been studied at 4, 22, and 38°C. The samples were exposed to synthetic air with careful control of CO2 concentration, relative humidity, and flow conditions. The relative humidity was 95%, and the concentrations of CO2 were <1 and 350 ppm, respectively. Sodium chloride was added before the exposures (0, 14, and 70 μnormalg/cm2 ). Mass gain and metal loss results are reported. As expected, NaCl is corrosive toward zinc, giving rise to heavy pitting. In the absence of CO2 , the rate of the NaCl‐induced corrosion was found to increase strongly with temperature. However, in the presence of CO2 , the corrosion rate of zinc is independent of temperature. In the absence of CO2 , zincite, ZnO, is the dominant corrosion product, while zinc hydroxy carbonates and simonkolleite, Zn5false(OH)8Cl2·H2O , dominate in the presence of CO2 . A mechanism is presented that explains the observations. © 2000 The Electrochemical Society. All rights reserved.

Transverse approach between tunnel environment and corrosion: Particulate matter in the Grand Mare tunnel

“…The atmospheric corrosion of zinc in the presence of NaCl and CO 2 is approximatively independent of temperature. The presence of CO 2 slows down NaCl-induced corrosion at 22 and 38 C (Lindström et al, 2000). In the presence of NaCl particles, similar corrosion rate was found after exposure to pure humid air or humid air containing gaseous pollutants SO 2 , NO 2 , O 3 , and NO 2 þO 3 (Chen, 2005).…”

“…With the amount of NaCl particles on copper surface lower than 15 mg/cm 2 , higher corrosion rate was found with <1 ppm CO 2 than with 350 ppm CO 2 (ambient level); but with higher amount of NaCl (>15 mg/cm 2 ), the corrosion was higher with 350 ppm CO 2 (Chen, 2005). It has been shown that CO 2 strongly influenced NaCl-induced atmospheric corrosion of zinc, aluminium, and magnesium, with a decreasing corrosion rate in the presence of ambient levels of CO 2 ( Lindström et al, 2000( Lindström et al, , 2002. CO 2 concentration inside the tunnel is higher than the ambient value.…”

“…Now, it is known that NaCl plays an important role in the atmospheric corrosion of materials and a substantial amount of work has been done in this field. In a humid pure air environment, the corrosion rate of zinc is proportional to the amount of NaCl added (Svensson and Johansson, 1993;Lindström et al, 2000). The degradation of copper or zinc substrates in the presence of NaCl accelerates according to the relative humidity (RH) and becomes very important at 95% RH.…”

Study on Atmospheric Corrosion Behavior of Q235 Galvanized steel in Substation

“…As shown in Figure 11, the main elements are Zn, C and O. Based on previous studies [8][9][10], the corrosive mechanism is proposed for galvanized steel under different air atmosphere. Firstly, zinc (Zn) reacts with oxygen (O) to form ZnO, which will further transform into Zn(OH) 2 under a certain humidity.…”

Atmospheric Corrosion of Corrugated Iron Roofing Sheet in Oil Producing Locations in Southeastern Nigeria

“…On a time scale it usually reaches and almost constant level [7]. High corrosion rates can be included by high concentrations of air pollutants such as SO 2 , NO 2 , and O 2 [8][9][10], low rain pH [11], low degrees of surface inclinations in the prevailing wind direction [12], and corrosion rate is always lower in rural areas than in urban and marine environment [6].…”