Statistical appraisal of the atmospheric corrosion of mild steel

According to ASTM G50‐76, materials have been exposed to atmospheres of Saudi Arabia. Environmental factors such as temperature, relative humidity and deposition rates of pollutants (Cl− and SO2) were investigated. X‐ray diffraction was used for characterization. Corrosion rates were determined by weight loss. As per ISO 9223, aggressivity classification was made. The results obeyed well with the empirical kinetics equation of the form C = Ktn, where K and C are the corrosion losses in mg/cm2 after 1 and t years of the exposure, respectively, and n is constant. Based on n values, the corrosion mechanisms of samples are predicted.

Section: Experimental Methodsmentioning

confidence: 92%

The effect of atmospheric pollution on materials damage

Syed

2012

“…As previously noted, EIS experiments were sensitive to changes in the immersion level and position of the clamp connection of the coins. This resulted, as described for highly corroded iron , in regular variations between different EIS parameters for each one of the coins. This can be seen in Figure , where the experimental values of the maximum phase angle, ϕ max , and the logarithm of the total impedance at 0.1 Hz ( Z −1 in the following) are depicted for replicate EIS experiments from ‘fresh’ and ‘aged’ eurocent coins and coin ADF06, dated in 1916.…”

Section: Resultsmentioning

confidence: 75%

Dating archaeological copper using electrochemical impedance spectroscopy. Comparison with voltammetry of microparticles dating

Doménech‐Carbó

Capelo

Piquero

et al. 2015

A methodology for dating copper/bronze archaeological objects aged under atmospheric environments using electrochemical impedance spectroscopy (EIS) is described. The method is based on the measurement of resistance associated to the growth of corrosion layers in EIS recorded upon immersion of the pieces in mineral water and applying a bias potential for the reduction of dissolved oxygen. Theoretical expressions for the time variation of such resistance following a potential rate law are presented. Equivalent expressions are derived and applied for estimating the variation of the tenorite/cuprite ratio from their specific voltammetric signals using voltammetry of microparticles data. Calibration curves were constructed from a set of well‐documented coins.

“…Both K and n are dependent on the type of metal and climatic parameters. The validity of the equation and its reliability to predict long-term corrosion has been demonstrated by many authors [17][18][19][20][21][22][23][24][25].…”

Section: Discussionmentioning

confidence: 99%

Atmospheric corrosion of carbon steel at marine sites in Saudi Arabia

Syed

2010

Atmospheric corrosion tests, according to ASTM G50-76, have been carried out in Saudi Arabia, at eight marine sites representing different environmental conditions. Environmental factors such as average temperature, average relative humidity, and deposition rates of atmospheric pollutants (Cl À and SO 2 ) was investigated. X-ray diffraction has been used to determine the composition of the corrosion products. Corrosion rates have been determined for each sample at each of the exposure sites via loss of weight. The obtained data were used for the classification of atmospheric aggressivity, according to ISO 9223. The results obeyed well with the empirical kinetics equation of the form C ¼ Kt n , where K and C are the corrosion losses in mg/cm 2 after 1 and t years of the exposure respectively, and n is constant. Based on n values, the corrosion mechanism of carbon steel is predicted. The major constituent of the rust formed in marine environment is goethite (a-FeOOH). Samples also show the presence of a large proportion of lepidocrocite (g-FeOOH) and small amounts of ferrihydrite and maghemite (a-Fe 2 0 3 ).