Sulfurous Acid Corrosion of Low Carbon Steel at Ordinary Temperatures - I. Its Nature

McLeod, W; Rogers, Raymond R.

doi:10.5006/0010-9312-22.5.143

Cited by 22 publications

(4 citation statements)

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“…The exact mechanism of reduction of S02 is stil) unclear although possible reaction schemes have been proposed by Rozenfeld' and MeLeod and Rogers. 19 From the thermodynamic perspective, however, the detailed mechanism is inconsequential and the energetics of the overall reduction reaction are more important. The overall cathodic reduction process may be simply written as:…”

Section: Redox Potentials During the Tarnishing Reactionmentioning

confidence: 99%

A Thermodynamic Perspective of Copper Tarnishing in Moist Air—SO₂

Chawla

Payer

1990

CORROSION

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The open-circuit potential (E"p) of alloy 600 in lithiated water at 25 to 200°C is more negative than the RHE potential, which indicates that the alloy exhibits a mixed electrode potential under these conditions. In the 200 to 350°C range, E op is close to the RHE potential.The inner layer of the oxide film formed at 200°C and above is composed of MeO, white its outer layer is probably composed of Me00H or Me(OH) 2 .With increasing temperature, the film thickness increases moderately between 25 and 200°C, but increases drastically above 200°C.The AC impedance measurements show significant changes in the electrochemical properties of films starting from 150°C.At 250°C, semiconductivity of the film changes from p-type at lower temperatures to n-type at higher temperatures.The occurrence of changes in the properties of oxide films was established by ex situ and in situ experiments (AES, semiconductivity, and AC impedance, respectively). ABSTRACTA thermodynamic perspective of the initial stages of copper tarnishing in moist air-S02 is presented. Previous experimental work has shown that in such a system the initial tarnish film consists mostly of a mixture of copper(I) oxide and copper(1) sulfide. Equilibrium criteria are used to calculate the Tonic composition of the adsorbed water layer on the surface of the untarnished and the tarnished metal at various gas precursor concentrations. Using the adlayer chemistry, the electrode potentials of the redox reactions in the system are determined. Thermodynamically stable corrosion products are then calculated. The ability of S02 dissolved in water to act as a cathodic depolarizer in this system, thereby forming sulfide in the tarnish film, is demonstrated.

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Section: Redox Potentials During the Tarnishing Reactionmentioning

confidence: 99%

A Thermodynamic Perspective of Copper Tarnishing in Moist Air—SO₂

Chawla

Payer

1990

CORROSION

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“…However, the formation of copper sulfide in an environment containing a moist oxidized sulfur species (SO2) requires explanation. Sulfur dioxide from the atmosphere dissolves readily in the water adlayer and the resulting sulfurous acid can act either as a reducing agent or an oxidizing agent (24). In fact, Rozenfeld (3) has shown that SO2 can act as a strong cathodic depolarizer by directly participating in the reduction reaction.…”

Section: ~Oo Z" _omentioning

confidence: 99%

The Early Stage of Atmospheric Corrosion of Copper by Sulfur Dioxide

Chawla

Payer

1990

J. Electrochem. Soc.

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The early stage of corrosion of copper by moist air containing 0.5% sulfur dioxide (75% relative humidity at 25~ has been studied. Scanning electron microscopy, Auger electron spectroscopy, and transmission electron microscopy have been used to examine the surface topography, surface chemistry, and microstructure of copper foils before and after exposure to the corrosive atmosphere. The analyses show that in the initial stage of corrosion a mixture of copper oxide and copper sulfide forms on the surface. Reduction of sulfur dioxide to sulfide on the metal surface indicates that sulfur dioxide is a cathodic depolarizer in the early stages of corrosion.

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“…22) McLeod and Rogers reported that SO 2 in the atmosphere easily dissolves into the surface electrolyte and that the resulting sulfurous acid (H 2 SO 3 ) can act either as a reducing agent or an oxidizing one. 27) We believe that there is a reduction route of bisulfite ions as follows. For copper, the bisulfite seen in the S 2p XPS spectra originated from SO 2 adsorption on the surface electrolyte, as shown in equation (1).…”

Section: )mentioning

confidence: 99%

Comparative XPS Study of Silver and Copper Surfaces Exposed to Flowing Air Containing Low Concentration of Sulfur Dioxide

Watanabe

Andō²,

Handa

et al. 2007

ZAKAEP

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Sulfur dioxide (SO 2 ), a typical gaseous compound found in the atmosphere, corrodes metals, particularly outdoors. When SO 2 adsorbs on the surface electrolyte, it easily dissolves, resulting in the formation of protons (H ) and bisulfite ions (HSO 3 ). The former reduces the pH of the surface electrolyte, which promotes metal dissolution.Silver and copper are commonly used in the electronic components and devices typically found in telecommunication equipment. Since silver and copper are affected by SO 2 , it is important to know the effects of SO 2 on their corrosion behavior to predict the life expectancy of the equipment. Such knowledge would also be useful for coping with anomalous situations, such as volcanic eruptions, in which the SO 2 concentration can exceed several hundred ppb. A previous study showed that silver and copper plates exposed to the atmosphere were severely corroded following the volcanic eruption on Miyake Island in 2000. 1)Much effort has been expended on clarifying the effects of SO 2 on atmospheric silver and copper corrosion. A number of laboratory experiments have been reported regarding the effects of exposure to high SO 2 concentrations. 2) 15)Using infrared reflection absorption spectroscopy (IRAS), Persson and Leygraf showed that sulfite formed on the surface of copper during the initial stage when it was exposed to 0.21 ppm SO 2 in flowing air at 80 relative humidity (RH).16) In situ analysis using IRAS and a quartz crystal microbalance by Ito et al.17) 18) revealed that sulfite like CuSO 3 Cu 2 SO 3 2H 2 O (Chevreul's salt) and sulfate CuSO 4 5H 2 O formed as corrosion products on copper exposed to flowing air containing 10 ppm SO 2 at 80 RH. Moreover, the formation rate of sulfite was higher than that of sulfate in the very early stage. 17) 18) In contrast, the sulfidation rate by SO 2 for silver is much lower than that by reduced sulfur species, such as H 2 S and COS. 12) Since SO 2 is considered to be a weak corrosive agent for silver, the effect of SO 2 on atmospheric silver corrosion in the initial stage has received little attention.In this study, the chemical state of the sulfur was investigated when silver and copper plates were exposed for one hour to flowing air containing low concentrations of SO 2 . Since the electrochemical reactions occur at the metal/ electrolyte interface in the early stage of corrosion, X-ray photoelectron spectroscopy (XPS) was used. The SO 2 concentrations were 18 and 148 ppb ; the former is at least one order of magnitude lower than those in previous studies. 16) 18)The silver and copper plates were 99.99 pure and 5 5 0.1 mm in size. Their surfaces were sputtered with 3 kV Ar ions to clean them. The sputtering was conducted until both carbon and oxygen were not detected in the XPS spectra, as described elsewhere. Sulfur dioxide (SO 2 ) is a typical gas affecting the atmospheric corrosion of metals, particularly outdoors. Although many studies have investigated the effect of SO 2 on the atmospheric corrosion of silver and copper, little is ...

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Sulfurous Acid Corrosion of Low Carbon Steel at Ordinary Temperatures - I. Its Nature

Cited by 22 publications

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A Thermodynamic Perspective of Copper Tarnishing in Moist Air—SO₂

A Thermodynamic Perspective of Copper Tarnishing in Moist Air—SO₂

The Early Stage of Atmospheric Corrosion of Copper by Sulfur Dioxide

Comparative XPS Study of Silver and Copper Surfaces Exposed to Flowing Air Containing Low Concentration of Sulfur Dioxide

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Sulfurous Acid Corrosion of Low Carbon Steel at Ordinary Temperatures - I. Its Nature

Cited by 22 publications

References 0 publications

A Thermodynamic Perspective of Copper Tarnishing in Moist Air—SO2

A Thermodynamic Perspective of Copper Tarnishing in Moist Air—SO2

The Early Stage of Atmospheric Corrosion of Copper by Sulfur Dioxide

Comparative XPS Study of Silver and Copper Surfaces Exposed to Flowing Air Containing Low Concentration of Sulfur Dioxide

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A Thermodynamic Perspective of Copper Tarnishing in Moist Air—SO₂

A Thermodynamic Perspective of Copper Tarnishing in Moist Air—SO₂