FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2116470540> ?p ?o ?g. }

• W2116470540 abstract "The morphology and composition of anodically formed alumina films on purealuminium are well characterised, but their structure is not well known due to the longrange order.Two systems have been looked at in this study; the nature of the structure of tungstenincorporated from tungstate electrolyte during polarisation of aluminium at 100 V, andthe other system is the thin passivating layers formed anodically on aluminium surfaceby polarisation within the range -2.2 - +2.5 V in aqueous solutions at various pH's.Even though other techniques, such as, electron microscopy and XPS have been used toconfirm the presence of anion species in alumina films only EXAFS can yield directinformation about the structure of incorporated species. In this study, EXAFS has beenused for the first time to resolve the structure of tungsten incorporated into anodicalumina. Accurate determination of structural parameters require the establishment ofreliable phase shift. By fitting the EXAFS of tungsten foil and potassium tungstate, thereliability of the calculated phase shifts for oxygen and tungsten was established.Based on phase shift transferability, the phase shifts calculated for 0 and W were usedin the fitting of fluorescence EXAFS of tungsten in alumina oxide films formed onaluminium in tungstate solution at 100V. The experimental EXAFS function was fittedto a single oxygen shell with four atoms at a distance of 1.79 ± 0.01 A. From thestructural parameters for incorporated tungsten it is clear that it is in a W042- eventhough this can not be the entity which is outwardly mobile. It is suggested that thetungstate may be linked in some way to the alumina and that because aluminium cationsare outwardly mobile so tungstate is dragged along.The other kind of anodic films on aluminium are those produced by polarisingaluminium in aqueous solutions at various pH's to various voltages within the range-2.2 - + 2.5 V. In some instances, passivating films grow on aluminium causingaluminium protection against corrosion. The structure of these films is not defined andbecause of their existence on aluminium, and their small thickness, so their structure isnot easy to be studied. Electron microscope and XPS techniques have been used todetermine their morphology and composition. Some work on indirectly extracting thestructure of these films from XPS data was reported and it was claimed that these filmshave a pseudoboehmite like structure.XPS results of these films reported in this study have confirmed that under open circuitconditions an oxide film forms, but to provide good corrosion protection aluminium ispolarised at different potentials. The oxide film which forms in these conditions hasbeen found to have both 4 and 6 coordiation. The Al K-edge EXAFS of these oxidefilms was fitted in the same way as those for the incorporated tungsten. In this case, theEXAFS of aluminium foil and alpha alumina was fitted by the use of phase shiftscalculated in EXCURV92 for aluminium and oxygen. The oxygen and aluminium phaseshifts calculated in EXCURV92 were reliable, so they were used to fit the EXAFS ofthe passivating films on aluminium of unknown structure. The EXAFS results in thisstudy have confirmed that these oxides do not have a single phase crystalline structurelike boehmite or any others. Their structure is of a short range order and it ischaracterised in terms of co-ordination number and shell distances. All of the resultsreported in the EXAFS section of this work indicate that these oxide films are relativelythin and that is indicated by a metallic aluminium signal present most of the time. Thesampling depth of the x-ray photons is much greater than the thickness of the oxide filmand for this reason a metallic signal was recorded. By comparing the bond length valueto the relation between the bond length and co-ordination number, it is obvious thatthese oxides films have a mixture of 4 and 6 co-ordination. In some cases, likealuminium polarised to + 0.9 V in pH 10, most of the co-ordination of the oxide is 6except a little of it in the 4 co-ordination.XANES spectra for the model compounds and those for oxide films on aluminium andtheir derivative have agreed with the EXAFS results about the structure of thin filmsformed on aluminium. Also these findings were complemented by the XPS data wherethe Al 2p of pseudoboehmite has a binding energy of 80.0 eV whilst that of the oxidefilms in general were - 74 eV. So, it is clear that the oxide films structure is not apsuedoboehmite, but it is a local one with different values for the bond length and as aconsequence a mixture of different (4 and 6) co-ordination." @default.
• W2116470540 created "2016-06-24" @default.
• W2116470540 creator A5077992019 @default.
• W2116470540 date "1998-02-01" @default.
• W2116470540 modified "2023-09-27" @default.
• W2116470540 title "Structural studies of anodic films on pure aluminium" @default.
• W2116470540 hasPublicationYear "1998" @default.
• W2116470540 type Work @default.
• W2116470540 sameAs 2116470540 @default.
• W2116470540 citedByCount "0" @default.
• W2116470540 crossrefType "dissertation" @default.
• W2116470540 hasAuthorship W2116470540A5077992019 @default.
• W2116470540 hasConcept C107861141 @default.
• W2116470540 hasConcept C113196181 @default.
• W2116470540 hasConcept C119824511 @default.
• W2116470540 hasConcept C120665830 @default.
• W2116470540 hasConcept C121332964 @default.
• W2116470540 hasConcept C127413603 @default.
• W2116470540 hasConcept C171250308 @default.
• W2116470540 hasConcept C175708663 @default.
• W2116470540 hasConcept C178790620 @default.
• W2116470540 hasConcept C179104552 @default.
• W2116470540 hasConcept C185592680 @default.
• W2116470540 hasConcept C191897082 @default.
• W2116470540 hasConcept C192562407 @default.
• W2116470540 hasConcept C2776477544 @default.
• W2116470540 hasConcept C2778648569 @default.
• W2116470540 hasConcept C2779227376 @default.
• W2116470540 hasConcept C2780927105 @default.
• W2116470540 hasConcept C42360764 @default.
• W2116470540 hasConcept C43617362 @default.
• W2116470540 hasConcept C44280652 @default.
• W2116470540 hasConcept C513153333 @default.
• W2116470540 hasConcept C542268612 @default.
• W2116470540 hasConcept C8010536 @default.
• W2116470540 hasConceptScore W2116470540C107861141 @default.
• W2116470540 hasConceptScore W2116470540C113196181 @default.
• W2116470540 hasConceptScore W2116470540C119824511 @default.
• W2116470540 hasConceptScore W2116470540C120665830 @default.
• W2116470540 hasConceptScore W2116470540C121332964 @default.
• W2116470540 hasConceptScore W2116470540C127413603 @default.
• W2116470540 hasConceptScore W2116470540C171250308 @default.
• W2116470540 hasConceptScore W2116470540C175708663 @default.
• W2116470540 hasConceptScore W2116470540C178790620 @default.
• W2116470540 hasConceptScore W2116470540C179104552 @default.
• W2116470540 hasConceptScore W2116470540C185592680 @default.
• W2116470540 hasConceptScore W2116470540C191897082 @default.
• W2116470540 hasConceptScore W2116470540C192562407 @default.
• W2116470540 hasConceptScore W2116470540C2776477544 @default.
• W2116470540 hasConceptScore W2116470540C2778648569 @default.
• W2116470540 hasConceptScore W2116470540C2779227376 @default.
• W2116470540 hasConceptScore W2116470540C2780927105 @default.
• W2116470540 hasConceptScore W2116470540C42360764 @default.
• W2116470540 hasConceptScore W2116470540C43617362 @default.
• W2116470540 hasConceptScore W2116470540C44280652 @default.
• W2116470540 hasConceptScore W2116470540C513153333 @default.
• W2116470540 hasConceptScore W2116470540C542268612 @default.
• W2116470540 hasConceptScore W2116470540C8010536 @default.
• W2116470540 hasLocation W21164705401 @default.
• W2116470540 hasOpenAccess W2116470540 @default.
• W2116470540 hasPrimaryLocation W21164705401 @default.
• W2116470540 hasRelatedWork W1500365658 @default.
• W2116470540 hasRelatedWork W1918997014 @default.
• W2116470540 hasRelatedWork W1972495220 @default.
• W2116470540 hasRelatedWork W1990104547 @default.
• W2116470540 hasRelatedWork W2004145066 @default.
• W2116470540 hasRelatedWork W2006576164 @default.
• W2116470540 hasRelatedWork W2007097306 @default.
• W2116470540 hasRelatedWork W2054559721 @default.
• W2116470540 hasRelatedWork W2067216961 @default.
• W2116470540 hasRelatedWork W2095066395 @default.
• W2116470540 hasRelatedWork W2224939729 @default.
• W2116470540 hasRelatedWork W2316911080 @default.
• W2116470540 hasRelatedWork W2317830284 @default.
• W2116470540 hasRelatedWork W2574401471 @default.
• W2116470540 hasRelatedWork W2783151782 @default.
• W2116470540 hasRelatedWork W2889861254 @default.
• W2116470540 hasRelatedWork W601205215 @default.
• W2116470540 hasRelatedWork W2342130335 @default.
• W2116470540 hasRelatedWork W2552343742 @default.
• W2116470540 hasRelatedWork W2866454359 @default.
• W2116470540 isParatext "false" @default.
• W2116470540 isRetracted "false" @default.
• W2116470540 magId "2116470540" @default.
• W2116470540 workType "dissertation" @default.