| 1. |
- Davoodi, Ali, et al.
(författare)
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Probing of local dissolution of Al-alloys in chloride solutions by AFM and SECM
- 2006
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 252:15, s. 5499-5503
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Tidskriftsartikel (refereegranskat)abstract
- Local dissolution of Al alloys was probed in situ in chloride solutions by using atomic force microscopy (AFM) and scanning electrochemical microscopy (SECM). Preferential dissolution in the boundary region between some intermetallic particles (IMPs) and alloy matrix, and trench formation around large IMPs during free immersion and under electrochemical anodic polarization were observed, which indicate different dissolution behavior associated to different types of IMPs. Moreover, by using an integrated AFM/SECM system with a dual mode cantilever/microelectrode probe, simultaneous probing of electrochemical active sites and topographic changes over the same area was performed with submicron resolution. This allowed the ongoing localized corrosion processes related to the IMP to be revealed.
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| 2. |
- Göthelid, Mats, et al.
(författare)
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Hexane selenol dissociation on Cu : The protective role of oxide and water
- 2017
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 423, s. 716-720
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Tidskriftsartikel (refereegranskat)abstract
- Hexane selenol (CH3(CH2)5SeH) was adsorbed from gas phase in ultra-high vacuum on polycrystalline Cu and studied with synchrotron radiation based photoelectron spectroscopy (PES) and Near edge X-ray absorption fine structure spectroscopy (NEXAFS). Adsorption was done on a bare copper surface at room temperature (RT), on a thin oxide on Cu at room temperature, and on a thin layer of water on Cu at 140 K.
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| 3. |
- Kleber, C., et al.
(författare)
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Comparison of the early stages of corrosion of copper and iron investigated by in situ TM-AFM
- 2002
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Ingår i: Applied Surface Science. - 0169-4332 .- 1873-5584. ; 193:1-4, s. 245-253
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Tidskriftsartikel (refereegranskat)abstract
- Tapping mode atomic force microscopy (TM-AFM) was used for the investigation of the early stages of atmospheric corrosion of pure copper and pure iron. The information obtained by this method is the change of the topography of the sample surfaces with emphasis on the. shape and lateral distribution of the corrosion products grown within the first 1300 min of weathering. Investigations were carried out in synthetic air at 80 and 90% relative humidity (RH) with additions of 250 ppb SO2 and 250 ppb NO2. On a polished copper surface the growth of corrosion products could be observed already at 80% RH and 250 ppb SO2, whereas an iron surface had to be exposed to 90% RH with 250 ppb SO2 and 250 ppb NO, to produce detectable changes on the surface.
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| 4. |
- Liu, Min, et al.
(författare)
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Density-functional theory investigation of Al pitting corrosion in electrolyte containing chloride ions
- 2015
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 357, s. 2028-2038
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Tidskriftsartikel (refereegranskat)abstract
- The behavior of chloride ions (Cl-) and oxygen species (the oxygen atom, O or molecular oxygen, O-2) on Al(1 1 1) surface has been studied by density functional theory calculations in order to deepen the molecular understanding of fundamental processes leading to pitting of aluminum (Al). The adsorption behavior of individual species, Cl-, O atom and O-2 was determined first. Subsequently, three possible scenarios in different pitting stages were modeled exploring the repassivation and dissolution of Al in neutral electrolyte containing Cl-. In scenario i, it was found that Cl- can hardly destroy even an O-monolayer on Al(1 1 1) surface, however may lead to the elongation of Al-O bond and the weakened binding between the first Al layer and subsequent Al layers. Both O-2 and Cl- were simultaneously introduced onto Al(1 1 1) in scenario ii. The result showed a weakened Al-O interaction and an intensive hybridization peak at -0.18 Ha between Al-3p with Cl-3p suggesting insufficient repassivation behavior of Al under this condition. Finally, scenario iii mimicked different local environmental conditions in pits formed on Al. At low coverage of Cl-, chloride ions had little effect on surface relaxation. The interaction among chloride ions and Al surface became stronger as Cl- coverage increased. Surface Al atoms dissolved gradually and substructures such as AlCl3 and Al2C15 formed when the coverage was larger than 2/3 ML of a monolayer.
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| 5. |
- Qiu, Ping, et al.
(författare)
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Initial Oxidation of Brass Induced by Humidified Air
- 2011
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 258:3, s. 1235-1241
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Tidskriftsartikel (refereegranskat)abstract
- Complementary surface and near-surface analytical techniques have been used to explore a brass (Cu-20Zn) surface before, during, and after exposure in air at 90% relative humidity. Volta potential variations along the unexposed surface are attributed to variations in surface composition and resulted in an accelerated localized growth of ZnO and a retarded more uniform growth of an amorphous Cu2O-like oxide. After 3 days the duplex oxide has a total mass of 1.3 μg/cm2, with improved corrosion protective properties compared to the oxides grown on pure Cu or Zn. A schematic model for the duplex oxide growth on brass is presented.
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| 6. |
- Wadsak, M., et al.
(författare)
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A comparison of preparation methods of copper surfaces for in situ scanning force microscopy investigations
- 2000
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Ingår i: Applied Surface Science. - 0169-4332 .- 1873-5584. ; 157:02-jan, s. 39-46
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Tidskriftsartikel (refereegranskat)abstract
- Scanning force microscopy (SFM) studies of atmospheric corrosion of pure copper require a clean, homogeneous and smooth metal surface in order to image small changes. In this study various preparation methods for samples of copper sheets were tested: chemical etching, mechanical polishing as well as electrochemical polishing. In addition to copper sheet samples also specimen of sputtered copper obtained by physical vapour deposition on quartz substrates were chemically etched. In conclusion, mechanical polishing with monocrystalline diamond paste and electrochemical polishing of copper sheet yielded the most suitable surface condition for in situ investigations by means of SFM. Tapping mode atomic force microscopy (TM-AFM) was applied to gain information about the topography changes of the copper surface. Furthermore, the root mean square (rms) roughness of the sample surfaces was determined and delivered additional arguments for the applicability of the various surface treatments for in situ studies.
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| 7. |
- Weissenrieder, Jonas, et al.
(författare)
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Photoelectron microscopy of filiform corrosion of aluminum
- 2003
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Ingår i: Applied Surface Science. - 0169-4332 .- 1873-5584. ; 218:1-4, s. 154-161
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Tidskriftsartikel (refereegranskat)abstract
- Aluminum samples have been investigated during and after exposure to well-controlled amounts of NaCl and humidified air. With infrared reflection absorption spectroscopy the deliquescence of NaCl crystallites could be followed in situ at high relative humidity (RH), as well as the growth of different aluminum oxide, hydroxide and chloride corrosion products. Investigations with scanning electron microscopy and energy dispersive X-ray analysis after exposure revealed the growth of filaments representative of filiform corrosion and chlorine enrichment in the filament heads. The exposed samples were further investigated with synchrotron based photoelectron microscopy/spectroscopy. Spectra taken of the Al 2p core level showed an intricate structure with multiple components in the core level. By means of mapping the intensity of the different chemical states within the core level the distribution of compounds over the surface could be determined. An enrichment of aluminum chloride containing compounds was found in the heads of the filaments, whereas aluminum oxides or hydroxides were observed both inside and outside the filaments.
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| 8. |
- Zhang, Xian, 1986-, et al.
(författare)
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The initial release of zinc and aluminum from non-treated Galvalume and the formation of corrosion products in chloride containing media
- 2011
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 258:10, s. 4351-4359
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Tidskriftsartikel (refereegranskat)abstract
- This study explores the initial release of zinc and aluminum from non-treated Galvalume and the parallel formation of corrosion products when exposed to synthetic seawater and rainwater of different chloride content. Comparisons were made with long-term field exposures at non-sheltered marine conditions. Observed release rates from short-term conditions agree qualitatively with the long-term findings with a selective release of zinc over aluminum. The release and corrosion processes were intertwined through the formation of corrosion products with properties that influence the long-term release process. Prior to exposure, Al2O3 dominated the entire surface, and was subject to local destruction upon interaction with chloride ions. As a consequence Al2O3 was gradually replaced and covered by zinc-rich corrosion products primarily in interdendritic areas during the first year of marine exposure. This was followed by the gradual formation and integration of aluminum-rich corrosion products, reflected by an increased zinc release rate during the first year, followed by a gradually decreased rate during subsequent years. The importance of Al2O3 was also evident in deaerated synthetic rainwater or seawater, where the formation of Al2O3 was presumably hindered. In synthetic rain water this resulted in a higher ratio between released aluminum and zinc compared with non-deaerated conditions.
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