The effect of conditioning by permanganate on the dissolution behavior of stellite particles in organic complexing acid medium

Subramanian, Veena; Chandramohan, P.; Srinivasan, M.; Sukumar, A.A.; Raju, V.S.; Velmurugan, S.; Narasimhan, S.V.

doi:10.1016/j.jnucmat.2004.05.015

Cited by 6 publications

(6 citation statements)

References 8 publications

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“…This sudden change in the system may be due to breakdown of passivity of the alloy. In our previous study [4], the XPS spectra for stellite #3 exhibited chromium in both metallic, as well as in Cr 2 O 3, form, while the cobalt was mostly present in its metallic form. Based on a calculation of escape depth for chromium through a Cr 2 O 3 layer, the chromium signals can be obtained only if the thickness of the film is less than 3.3 nm [11].…”

Section: Eis Measurements At 90°c With Increase In Exposure Timementioning

confidence: 71%

“…Corrosion takes place more or less uniformly in HMnO 4 and hence the surface morphology shows broken carbides and reduced area fractions for all the phases after the completion of one redox step. From XPS and SEM analysis it may be concluded that both cobalt and chromium gets oxidized to form a thin film.…”

Section: Surface Characterizationmentioning

confidence: 99%

“…Extensive studies on the dissolution of stellite #3 in the form of metallic powder have shown that acidified permanganate reagents are more efficient in dissolving chromium and cobalt from this alloy as compared to alkaline permanganate [4]. Among the acidified permanganate reagents also, permanganic acid (HMnO 4 , used in the CORD process) [5] has better dissolution capabilities as compared to Nitric acid Permanganate(NP) of similar acidity.…”

Section: Introductionmentioning

confidence: 99%

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Effect of nitrate ions on the corrosion of stellite in permanganate media

et al. 2009

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The dissolution behaviour of stellite #3 in two oxidizing agents of equivalent acidity namely, permanganic acid (HMnO 4 ) and a mixture of nitric acid and potassium permanganate (NP) was evaluated. The presence of nitrate in the permanganate formulation was found to reduce its efficiency for oxidizing stellite. Electrochemical polarization and impedance studies were carried out at 90°C in NP and HMnO 4 . The redox potential of both the oxidizing agents favoured transpassive dissolution of chromium from the alloy. In NP, only the chromium depleted inter-phase boundary was attacked while most of the chromium rich carbide phases were intact. In contrast, in HMnO 4 , uniform corrosion of the surface was observed. The impedance response was found to change with duration of exposure. The nitrate ions in permanganate were found to promote the repassivation of the surface. HMnO 4 was found to be a better formulation for dissolving cobalt from the alloy as compared to NP.

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Section: Eis Measurements At 90°c With Increase In Exposure Timementioning

confidence: 71%

Section: Surface Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of nitrate ions on the corrosion of stellite in permanganate media

et al. 2009

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“…Stachowiak and Zwierzycki (2012) studied the tribocorrosion mechanism of stainless steel in both sulfuric acid and NaCl solution and showed that the formed surface passivation film helped in the reduction of surface deformation under low contact stress and weak corrosive medium circumstances. Subramanian et al revealed that the exposure of steel to radiation may enhance tribocorrosion as it affects corrosion kinetics (Subramanian et al, 2004). Accordingly, the surface corrosion kinetics change resulted from irradiation cannot be ignored.…”

Section: Introductionmentioning

confidence: 99%

Preliminary investigation on the effect of irradiation on tribocorrosion behavior of 316L stainless steel alloy

Farid

Moamen

Shehata

2019

Journal of Radiation Research and Applied Sciences

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The effect of irradiation on the tribocorrosion behavior of 316L stainless steel alloy was investigated in 0.02 M Na 2 SO 4 solution, using a ball-on-flat configuration, which was connected with a three electrode-chemical cell. The rubbing and irradiation track morphology were investigated using Scanning Electron Microscopy and profilometric measurements after rubbing and irradiation tests. The rubbing tests, in the presence or absence of irradiation, were performed under 20 N normal force using an alumina ball as a counter body. The surfaces were characterized through electrochemical measurements, optical microscopy, and elemental analysis while the corrosion phenomenon was examined by electrochemical impedance spectroscopy (EIS) and polarization potentiodynamic measurements. The open-circuit potential measurements and EIS measurements were used to evaluate the electrochemical reactivity of the 316L stainless steel surface before, during and after sliding tests. The corrosion rate was determined using the Tafel extrapolation technique. It was found that when the sample subjected to both tribo-corrosion and irradiation, the corrosion potential shifted more toward the anodic region and affects the corrosion kinetics. It is found that the surface of 316L stainless steel has a reasonable corrosion-irradiation resistance.

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“…Activated stellite particulates have also been observed to be deposited on the stainless steel vessels of moderator system. 1 During moderator decontamination of hot spots, zircaloy-2 will also come in contact with the decontamination solution. Dilute chemical decontamination process is one of the methods adopted to remove the activity embedded in the oxide layers formed over these structural materials.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical study on corrosion behaviour of zircaloy-2 in aqueous medium containing permanganate ion

Sumathi¹,

Bera²,

Rangarajan³

2013

Corrosion Engineering, Science and Technology

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The corrosion compatibility of zircaloy-2 was studied in strong oxidising permanganate based acidic (HMnO 4 ) medium using impedance spectroscopy and potentiodynamic anodic polarisation methods at room temperature (28uC) and elevated temperatures (65 and 90uC). The average corrosion rate of zircaloy-2 in HMnO 4 medium (0?417-8?33 mM) was found to be 1?326 10 24 mm h 21 at 28uC, 2?59610 24 mm h 21 at 65uC and 3?53610 24 mm h 21 at 90uC. At 28uC, the polarisation resistance R p values obtained from impedance spectrum were higher (in kV) when compared to R p values at 65 and 90uC, indicating a lower corrosion rate at lower temperature. Comparative studies with 2?5 mM H 2 SO 4 and platinum (as a working electrode) showed the effects of oxidising nature and participation of additional redox reactions in HMnO 4 medium. Cyclic polarisation studies showed the absence of pitting attack on zircaloy-2. Experimental Materials and solutionsThe sample coupons of zircaloy-2 (Zr-1?5Sn-0?15Fe-0?1Cr-0?05Ni; size, 161 cm) were polished with different grades of silicon carbide papers ranging from 80 to

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The effect of conditioning by permanganate on the dissolution behavior of stellite particles in organic complexing acid medium

Cited by 6 publications

References 8 publications

Effect of nitrate ions on the corrosion of stellite in permanganate media

Effect of nitrate ions on the corrosion of stellite in permanganate media

Preliminary investigation on the effect of irradiation on tribocorrosion behavior of 316L stainless steel alloy

Electrochemical study on corrosion behaviour of zircaloy-2 in aqueous medium containing permanganate ion

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