XPS studies of dc and ac anodic films on aluminium formed in sulphuric acid

Treverton, J. A.; Davies, N. C.

doi:10.1016/0013-4686(80)80006-5

Cited by 35 publications

(13 citation statements)

References 21 publications

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“…The binding energies for phosphor and sulfur, as derived from the P 2s and S 2p photopeaks, are 191.6 (±0.3) eV and 169.7(±0.4) eV (Table ). Only one specie is present for each element, with a position that corresponds to P in PO 4 3– and S in SO 4 2– states, confirming our previous AES observations. The oxidation state of chromium is predominantly Cr(VI) detected at 579.4 (±0.1) eV and 587.8 (±0.2) eV for Cr 2p 3/2 and Cr 2p 1/2 , respectively (not shown) .…”

Section: Resultssupporting

confidence: 89%

XPS Analysis of the Surface Chemistry and Interfacial Bonding of Barrier-Type Cr(VI)-Free Anodic Oxides

Abrahami

Hauffman

Kok³

et al. 2015

J. Phys. Chem. C

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In the transition to environmental friendly pretreatment of aerospace aluminum alloys, chromic acid anodizing (CAA) is being replaced by sulfuric acid (SAA), phosphoric acid (PAA) or phosphoric-sulfuric acid (PSA) anodizing. While generally the main concern is controlling the film morphology, such as the pore diameter, oxide-, and barrier layer thickness, little is known on how the anodic oxide chemistry affects the interactions at the interface upon adhesive bonding. To study the link between surface chemistry and interfacial bonding, featureless oxides were prepared by stopping the anodizing during the formation of the barrier layer. A model was developed to quantify the relative amounts of OH -, PO 4 3-and SO 4 2-by curve-fitting the XPS data.Calculations showed that almost 40% of the surface species in PAA oxide are phosphates (PO 4 3-), while about 15% are sulfates (SO 4 2 ) in SAA. When both anions were present in the electrolyte, phosphate incorporation was inhibited. Studies of the interaction between this set of Cr(VI)-free oxides and diethylenetriamine (DETA) -an amine curing-agent for epoxy resin, showed that all oxides interact with the nitrogen of DETA. However, larger ratios of Lewis-like acid-base bonding between the amine electron pair and the acidic hydroxyl on phosphate surface sites were observed.

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Section: Resultssupporting

confidence: 89%

XPS Analysis of the Surface Chemistry and Interfacial Bonding of Barrier-Type Cr(VI)-Free Anodic Oxides

Abrahami

Hauffman

Kok³

et al. 2015

J. Phys. Chem. C

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“…Table shows the binding energies recorded for some major elements prior to ion etching and Figure shows the appearance of the S-peak prior to etching and after 10 min. It has been reported that Cr 2p3/2 in Cr 2 (SO 4 ) 3 is located at 578.5 eV and S in Al 2 (SO 4 ) 3 is at 171.0 eV . Therefore, these sulfates are excluded.…”

Section: Resultsmentioning

confidence: 99%

“…It has been reported that Cr 2p3/2 in Cr 2 (SO 4 ) 3 is located at 578.5 eV 25 and S in Al 2 (SO 4 ) 3 is at 171.0 eV. 26 Therefore, these sulfates are excluded. Instead, it is likely that Fe sulfate 27,28 is formed at the outermost surface.…”

Section: ■ Resultsmentioning

confidence: 99%

Mitigation of Fireside Corrosion in Power Plants: The Combined Effect of Sulfur Dioxide and Potassium Chloride on the Corrosion of a FeCrAl Alloy

et al. 2014

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The corrosion behavior of a FeCrAl alloy (Kanthal APMT) was investigated in 5% O 2 with 40% H 2 O plus 300 ppm of SO 2 at 600°C in the presence or absence of KCl, and the results were also compared to exposures performed without SO 2 and KCl. The influence of preoxidation was also examined. The kinetics was followed using mass gain measurements, and the formed corrosion products were examined using XRD, SEM/EDX, AES, IC, and SIMS. The oxidation rate of Kanthal APMT was very low in O 2 /N 2 /H 2 O + 300 ppm of SO 2 , and the outward alumina growth appeared to be suppressed. Interestingly, no sulfur was detected at the scale/metal interface. KCl strongly accelerated the corrosion of Kanthal APMT in O 2 /H 2 O/N 2 at 600°C , forming K 2 CrO 4 and gaseous HCl. Chromate formation depletes the protective scale in Cr, triggering the formation of a fast growing iron-rich scale. Adding SO 2 suppressed the corrosion due to the conversion of the corrosive KCl to the stable K 2 SO 4 . If any K 2 CrO 4 was formed on the surface of the material initially, it was also rapidly converted to K 2 SO 4 . Preoxidation of Kanthal APMT had a strong beneficial effect on the subsequent exposure at 600°C in the presence of KCl and SO 2 , resulting in the formation of K 2 SO 4 and the evaporation of HCl and KCl. In summary, the alumina-forming FeCrAl material Kanthal APMT is not completely inert to KCl in an oxidizing SO 2 -containing atmosphere at 600°C. However, the corrosion rate is significantly lower than that of the commonly used chromia-forming alloy, 304L. Preoxidation decreases the corrosion rate even further, making Kanthal APMT a promising candidate material for combustion plant components, particularly from a corrosion point of view.

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“…The structures were similar to those prepared by dc anodization at the early stage [74]; however, those shapes were not retained after extended or high-voltage anodization [73]. The composition of the film prepared in sulfuric acid was estimated and the sulfur content was not related to the anodizing conditions [85, 101]. The effects of current density or potential and electrolyte temperature and concentration on film growth were also investigated [102].…”

Section: Ac Anodizationmentioning

confidence: 99%

Fabrication of alumina films with laminated structures by ac anodization

Segawa

Okano

Wada

et al. 2014

Science and Technology of Advanced Materials

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Anodization techniques by alternating current (ac) are introduced in this review. By using ac anodization, laminated alumina films are fabricated. Different types of alumina films consisting of 50–200 nm layers were obtained by varying both the ac power supply and the electrolyte. The total film thickness increased with an increase in the total charge transferred. The thickness of the individual layers increased with the ac voltage; however, the anodization time had little effect on the film thickness. The laminated alumina films resembled the nacre structure of shells, and the different morphologies exhibited by bivalves and spiral shells could be replicated by controlling the rate of increase of the applied potentials.

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XPS studies of dc and ac anodic films on aluminium formed in sulphuric acid

Cited by 35 publications

References 21 publications

XPS Analysis of the Surface Chemistry and Interfacial Bonding of Barrier-Type Cr(VI)-Free Anodic Oxides

XPS Analysis of the Surface Chemistry and Interfacial Bonding of Barrier-Type Cr(VI)-Free Anodic Oxides

Mitigation of Fireside Corrosion in Power Plants: The Combined Effect of Sulfur Dioxide and Potassium Chloride on the Corrosion of a FeCrAl Alloy

Fabrication of alumina films with laminated structures by ac anodization

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