Title: A Study on Corrosion-Process of Iron by Means of Electron Diffraction
Abstract: A systematic study was made on corrosion-products of iron by means of electron and X-ray diffraction, with the following results; When metallic iron is immersed in salt solution, amorphous white precipitate, Fe(OH) 2 , is formed as the primary corrosion-product. (1) Fe(OH) 2 thus formed changes into lepidocrocite, γ-Fe 2 O 3 .H 2 O, when pH of the solution so very low and oxidation takes place rapidly, while under usual conditions it is oxydized partly lepidocrocite, which combines with the remaining Fe(OH) 2 to form green rust, 2FeO.Fe 2 O 3 .H 2 O. (2) The green rust is oxydized, under usual conditions, to lepidocrocite, while in case oxygen in the solution is less, it changes partly to lepidocrocite, which combines with the remaining green rust giving magnetite, Fe 3 O 4 . On the other hand, when oxidation is accelerated by H 2 O 2 , it changes to haematite, α-Fe 2 O 3 . (3) Goethite, α-Fe 2 O 3 .H 2 O, was never observed in corrosin-products of metallic iron, and it was concluded that it is formed only from ferric salts: for example from the unstable yellow substance, which is precipitated in aqueous FeCl 3 solution under certain conditions. (4) This very substance was assumed as β-Fe 2 O 3 .H 2 O by Weiser and Milligan, but it is more reasonable to identify it with Fe(OH) 3 isomorphous to Al(OH) 3 . Its unit cell was determined by X-ray data:- monoclinic, a=8.99, b=5.12, c=9.92 and β=86^°34'.
Publication Year: 1951
Publication Date: 1951-09-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 9
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