ChemInform Abstract: ELECTRON DIFFRACTION STUDY OF THE PASSIVE FILM ON IRON

Abstract

In einer elektrochemischen Zelle mit Borat‐Puffer‐Lösungen (pH 8.4) passivierte Fe‐Proben zeigen Beugungsbilder für Fe‐Oxid vom Spinell‐Typ, unabhängig vom Passivierungspotential (O.4‐l.6 V).

Ex Situ Surface Analysis of Passive Films on Fe‐Cr Alloys: When Is It Valid?

“…the work by Mattson and Holm t'2 and Gradel et aI. [3][4][5][6][7] The interest in the effects of SO2 stems to a large extent from its role as one source for the sulfate that is usually found in the corrosion products of copper exposed to the urban atmosphere, be it indoors or outdoors.…”

Electrochemical Behaviour of Iron in NaOH 0.01 mol/L Solutions Containing Variable Amounts of Silicate

“…Many investigations were carried out using highly alkaline solutions [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] or using buffer solutions as carbonate/bicarbonate [19][20][21][22][23][24][25][26] or borate buffer [27][28][29][30][31][32] when a constant and not very high pH is desirable. Many products have been identified as resulting from the anodic polarization of iron at different potentials, by different surface analysis techniques [6][7][8][9][10][11][12][13]22,26,[33][34][35][36][37][38][39][40]…”

“…Several electrochemical techniques have also been used to investigate the kinetics of the formation of these products and among them cyclic voltammetry is one of the most used [2][3][4][5][6][7][8][14][15][16][17][18][19][20][21][22] . The surface analysis techniques that perform in-situ analysis have the great advantage of avoiding decomposition and/or dehydration of products formed which is inevitable with ex-situ analysis due to the high vacuum conditions and to the heating promoted by electron bombardment 1,14,28,[33][34][35][36][37][38] .…”

“…In-situ UV and visible spectroscopy techniques have also determined such a bi-layer structure 15 . Another proposition for the film passive composition based in elipsometric results 7 , XANES in-situ 27,28 and other optical techniques 37,39,44 The in-situ analysis results show that the film presents an amorphous character due to water presence which is an Article essential factor for passivation and this amorphous character is destroyed if the film is dried 10,14,34,35 . When a passive film is described as a double layer film, the inner layer is considered a barrier layer and the outer layer is a substrate for Fe(II)/Fe(III) redox reactions during potential cycling 6,7,22,42,43 .…”

High-resolution transmission electron microscopy study of epitaxial oxide shell on nanoparticles of iron

“…12 Although the mechanism of epitaxy is not yet known, the growth of epitaxial ␥-Fe 2 O 3 on iron can be understood using the Caberra-Mott theory of oxidation of metal. We have established beyond any doubt the epitaxial growth of ␥-Fe 2 O 3 on nanoparticles of iron.…”