Electrochemical studies of hydrogen diffusion and permeability in Ni

Atrens, Andrej; Mezzanotte, D.A.; Fiore, N.F.; Genshaw, M. A.

doi:10.1016/0010-938x(80)90102-x

Cited by 81 publications

(53 citation statements)

References 13 publications

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“…SCC is particularly dangerous because it can lead to fast fracture at mechanical loads considered safe in the absence of the environment. Our work on Mg stress corrosion cracking builds on our considerable experience in this area [60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76] Our recent review [8] aims to provide a foundation for the safe and effective use of Mg alloys, including practical guidelines for the service use of Mg alloys in the atmosphere and/ or in contact with aqueous solutions. This is to provide support for the rapidly increasing use of Mg in industrial applications, particularly in the automobile industry.…”

Section: Stress Corrosion Crackingmentioning

confidence: 99%

Recent Insights into the Mechanism of Magnesium Corrosion and Research Suggestions

Song¹,

Atrens²

2007

Adv Eng Mater

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281

121

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Magnesium (Mg) is the most reactive engineering material and corrosion protection continues to be an issue of great importance. [1][2][3][4] This note builds on prior reviews [1][2][3][4][5][6][7][8] and our research on Mg corrosion. [1,2, The corrosion performance of Mg alloys results from (1) the high intrinsic dissolution tendency of Mg, which is only weakly inhibited by corrosion product films and (2) the presence of impurities and second phases acting as local cathodes and thus causing local microgalvanic acceleration of corrosion.The corrosion mechanism includes all physical features and chemical reactions when metallic Mg is exposed to an environment. Our prior work [2,5,11,12] has indicated that the Mg corrosion mechanism has the following key points. In the general case, a partially protective film covers the surface of Mg and Mg dissolution occurs at breaks in this film. Hydrogen (H) evolution is associated with Mg dissolution in two separate ways. (a) An electrochemical reaction, Equation 1, balances the Mg dissolution reaction, Equation 2. (b) H is also produced directly by the reaction of Mg + with water, Equation 3.The overall reaction consumes H + and produces OH -, i.e. the pH increases, which favours the formation of Mg hydroxide film by the precipitation reaction. Mg has a negative corrosion potential, with a slightly more negative pitting potential, in solutions of practical importance like 3 % NaCl. The chance development of areas of localized corrosion leads to undermining and falling out of particles of Mg, even for the corrosion of pure Mg. New Insights: Mg +There continues to be some controversy as to the existence of Mg + as an intermediate in the reaction sequence between metallic Mg and Mg 2+ , the stable Mg ionic species in aqueous solutions. The evidence in support of the existence of Mg + is strong but circumstantial. The evidence in favor is based on the fact that the simplest possible reaction sequence, which includes Reactions 2 and 3, is consistent with all the experimental evidence, particularly the electrochemical impedance spectroscopy. [12] It is also supported by the observations of Song and co-workers [5,16,19] that the Mg corrosion mechanism involves "anodic H evolution" which is different to "cathodic H evolution".Negative Difference Effect (NDE): Mg has an exceedingly strange phenomenon, the negative difference effect (NDE). The NDE continues to receive considerable discussion. The NDE has been defined in our previous publications [1,2,5,11,12] in terms of the difference D:where I s is the spontaneous rate of the H evolution reaction (HER) on the Mg surface at the free corrosion potential, I H,m is the measured HER rate for an applied galvanostatic current I appl , which is equal to I appl I Mg;m À I H;m 5where I Mg,m is the measured rate of Mg corrosion. For most metals like Fe and Zn, in an acid solution, when the potential is increased, the anodic dissolution rate increases and the cathodic H evolution rate decreases. For these cases, D is greater than zero because I ...

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Section: Stress Corrosion Crackingmentioning

confidence: 99%

Recent Insights into the Mechanism of Magnesium Corrosion and Research Suggestions

Song¹,

Atrens²

2007

Adv Eng Mater

Self Cite

281

121

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“…Figure 1 illustrates the permeation cell [4,86], which is widely used [19,20,22,23,[117][118][119][120][121][122][123][124][125][126][127][128][129][130][131][132][133][134], and was used in this research project. Hydrogen is produced by the applied cathodic potential on the left hand side of the specimen, by the electrochemical cell on the left hand side of the specimen.…”

Section: Permeation Cellmentioning

confidence: 99%

“…This research was based on past research (i) in evaluating steel properties under the influence of H [79][80][81][82][83][84][85]], (ii) in evaluating H diffusion [86], (iii) on HE and stress corrosion cracking (SCC) [87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102][103][104][105], and related research [106][107][108][109][110][111].…”

Section: Aimsmentioning

confidence: 99%

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Influence of Hydrogen on Steel Components for Clean Energy

Atrens

Liu

Tapia-Bastidas

et al. 2018

CMD

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The influence of hydrogen on the mechanical properties of four, medium-strength, commercial, quenched-and-temped steels has been studied using the linearly increasing stress test (LIST) combined with cathodic hydrogen charging. The relationship was established between the equivalent hydrogen pressure and the hydrogen charging overpotential during cathodic hydrogen charging, though the use of electrochemical permeation experiments and thermal desorption spectroscopy. The cathodic hydrogen charging conditions were equivalent to testing in gaseous hydrogen at hydrogen fugacities of over a thousand bar. Under these hydrogen-charging conditions, there was no effect of hydrogen up to the yield stress. There was an influence of hydrogen on the final fracture, which occurred at the same stress as for the steels tested in air. The influence of hydrogen was on the details of the final fracture. In some cases, brittle fractures initiated by hydrogen, or DHF: Decohesive hydrogen fracture, initiated the final fracture of the specimen, which was largely by ductile micro-void coalescence (MVC), but did include some brittle fisheye fractures. Each fisheye was surrounded by MVC. This corresponds to MF: Mixed fracture, wherein a hydrogen microfracture mechanism (i.e., that producing the fisheyes) competed with the ductile MVC fracture. The fisheyes were associated with alumina oxide inclusion, which indicated that these features would be less for a cleaner steel. There was no subcritical crack growth. There was essentially no influence of hydrogen on ductility for the hydrogen conditions studied. At applied stress amplitudes above the threshold stress, fatigue initiation, for low cycle fatigue, occurred at a lower number of cycles with increasing hydrogen fugacity and increasing stress amplitude. This was caused by a decrease in the fatigue initiation period, and by an increase in the crack growth rate. In the presence of hydrogen, there was flat transgranular fracture with vague striations with some intergranular fracture at lower stresses. Mechanical overload occurred when the fatigue crack reached the critical length. There was no significant influence of hydrogen on the final fracture.

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“…Electrochemical hydrogen permeation test (ECHPT) [14][15][16][17][18] is an useful technique to observe changes in hydrogen entry with time, and many researchers have taken advantages of ECHPT to elucidate hydrogen uptake behavior under atmospheric exposure and simulated atmospheric corrosion. [19][20][21][22][23][24][25][26][27] In our previous study, it was found using ECHPT during cyclic corrosion test (CCT) that the rust later formed during atmospheric corrosion has an important role on enhancing hydrogen entry.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Hydrogen Permeation Test under Controlled Temperature and Humidity after Outdoor Exposure at Beijing, Chongqing and Okinawa

Akiyama

Katayama

et al. 2016

ISIJ Int.

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Electrochemical hydrogen permeation tests were carried out under controlled temperature and humidity using pure Fe sheet specimens outdoor-exposed at Beijing and Chongqing, China and Okinawa, Japan in order to understand the effect of environmental factors on hydrogen uptake behavior. The maximum hydrogen permeation current densities of the exposed specimens were in the order of Beijing > Chongqing >> Okinawa, while the order of the degree of corrosion of the specimens was Okinawa > Chongqing >> Beijing. X-ray fluorescence analysis showed that the surface concentrations of sulfur on the Beijing-and Chongqing-exposed specimens were higher than that of the Okinawa-exposed specimens, whereas chlorine concentrations of the Beijing and Okinawa-exposed specimens were higher than that of the Chongqingexposed specimen. Nitrate concentrations of Beijing-and Chongqing-exposed specimens evaluated using nitrate test strips were obviously higher than that of the Okinawa-exposed specimens. It is suggested that air pollutants such as SO 2 and NO 2 and particulate matters containing inorganic acid ions, likely surfate and nitrate ions, and possibly organic acids contribute to acidification of rust layer leading to the enhanced hydrogen entry.

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Electrochemical studies of hydrogen diffusion and permeability in Ni

Cited by 81 publications

References 13 publications

Recent Insights into the Mechanism of Magnesium Corrosion and Research Suggestions

Recent Insights into the Mechanism of Magnesium Corrosion and Research Suggestions

Influence of Hydrogen on Steel Components for Clean Energy

Electrochemical Hydrogen Permeation Test under Controlled Temperature and Humidity after Outdoor Exposure at Beijing, Chongqing and Okinawa

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