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Trans-passive

Cid etal. studied the corrosion resistance of Ni, 5% Fe-Ni and 10% Fe-Ni alloys in the trans-passive region in sulphuric acid. For a given acid concentration the addition of iron reduced the corrosion rate. It was concluded that the addition of small percentages of Fe was doubly beneficial, decreasing both general and intergranular corrosion. [Pg.583]

Pb02 film -PbO film Trans-passive region... [Pg.814]

FIGURE 22.7 Polarization curves forthe anodic dissolution and the passivation of metallic iron in 0.5 kmolm 3 sulfuric acid solution at 25°C [9,10] fpe = anodic iron dissolution current, io7 — oxygen evolution current, p = passivation potential, and Etp — trans-passivation potential. [Pg.545]

Numerous studies have attempted to elucidate the role of Mo in the passivity of stainless steel. It has been proposed from XPS studies that Mo forms a solid solution with CrOOH with the result tiiat Mo is inhibited from dissolving trans-passively [9]. Others have proposed that active sites are rapidly covered with molybdenum oxyhydroxide or molybdate salts, thereby inhibiting localized corrosion [10]. Yet another study proposed that molybdate is formed by oxidation of an Mo dissolution product [11]. The oxyanion is then precipitated preferentially at active sites, where repassivation follows. It has also been proposed that in an oxide lattice dominated by three-valent species of Cr and Fe, ferrous ions will be accompanied by point defects. These defects are conjectured to be canceled by the presence of four- and six-valent Mo species [1]. Hence, the more defect-free film will be less able to be penetrated by aggressive anions. A theoretical study proposed a solute vacancy interaction model in which Mo " is assumed to interact electrostatically with oppositely charged cation vacancies [ 12]. As a consequence, the cation vacancy flux is gradually reduced in the passive film from the solution side to the metal-film interface, thus hindering vacancy condensation at the metal-oxide interface, which the authors postulate acts as a precursor for localized film breakdown [12]. [Pg.223]

Line 3 represents stable passivation. The anodic and cathodic lines cross at a single point and a corrosion potential is set up at point E, well inside the passive region. However, increasing the cathodic current even more could drive the potential to point F in the trans-passive region, where corrosion and pitting could occur. [Pg.282]

Of an ion through the double layer towards the electrode and inhibits its transfer in the reverse direction or vice versa f< an, anodic process frequently experirtiental vajups of a aib approximately () 5. Tran assivity active behaviour of a metal atipotehtials, more positive than thbise ieading to passivity. [Pg.1374]

Various ways that a charged compound may cross a membrane by a passive mechanism have been described [42]. These include transport as ion (trans- and/or paraceUular), ion-pair or protein-assisted (using the outer surface of a protein spaiming a membrane). [Pg.32]

Malik, A.S., and Choi, T.S., Application of passive techniques for three-dimensional cameras, IEEE Trans. Cons. Elec. 53, 258, 2007. [Pg.261]

Carrier-mediated transport, Active Efflux, Passive (trans and para cellular) diffusion... [Pg.430]

Lorenz, M. Hochmuth, H. Natusch, D. Lippold, G. Svetchnikov, V. L. Kaiser, T. Hein, M. A. Schwab, R. Heidinger, R. 1999. Ag-doped double-sided PLD-YBCO thin films for passive microwave devices in future communication systems. IEEE Trans. Appl. Supercond. 9 1936-1939. [Pg.237]

Pade V, Stavchansky S (1997) Estimation of the relative contribution of the tran-scellular and paracellular pathway to the transport of passively absorbed drugs in the Caco-2 cell culture model. Pharm Res 14 1210-1215. [Pg.679]

The successful application of in vitro models of intestinal drug absorption depends on the ability of the in vitro model to mimic the relevant characteristics of the in vivo biological barrier. Most compounds are absorbed by passive transcellular diffusion. To undergo tran-scellular transport a molecule must cross the lipid bilayer of the apical and basolateral cell membranes. In recent years, there has been a widespread acceptance of a technique, artificial membrane permeation assay (PAMPA), to estimate intestinal permeability.117118 The principle of the PAMPA is that, diffusion across a lipid layer, mimics transepithelial permeation. Experiments are conducted by applying a drug solution on top of a lipid layer covering a filter that separates top (donor) and bottom (receiver) chambers. The rate of drug appearance in the bottom wells should reflect the diffusion across the lipid layer, and by extrapolation, across the epithelial cell layer. [Pg.176]

Prathiba J, Kumar KB, Karanth KS. Effects of neonatal clomipramine on cholinergic receptor sensitivity and passive avoidance behavior in adult rats. J Neural Trans Gen Sec 1995 100 93-99. [Pg.146]

Fig. 12.1 Schematic representation of the three transepithelial intestinal pathways (a) trans-cellular active transport, (b) transcellular passive transport, (c) paracellular transport (Fasano... Fig. 12.1 Schematic representation of the three transepithelial intestinal pathways (a) trans-cellular active transport, (b) transcellular passive transport, (c) paracellular transport (Fasano...
U. R. Evans, Trans. Electrochem. Soc. 91 547 (1947). Isolation of a film from a passive metal by dissolving away the metal. [Pg.220]

Fig. S. 7r-Fr characteristics of the a-Si H-passivated diode after various treatments. as deposited (1) after BT at 200X, 5 V (2) after HT at 300°C (3) after HT at 350 C (4) after HT at 500°C (5) after HT at 550X (6) after HT at 600°C (7) after HT at 650°C / thermal Si02 passivated diode. [From M. L. Tarng and J. I. Pankove, Passivation of p-n junction in crystalline silicon by amorphous silicon, IEEE Trans. Electron Devices, 1979.]... Fig. S. 7r-Fr characteristics of the a-Si H-passivated diode after various treatments. as deposited (1) after BT at 200X, 5 V (2) after HT at 300°C (3) after HT at 350 C (4) after HT at 500°C (5) after HT at 550X (6) after HT at 600°C (7) after HT at 650°C / thermal Si02 passivated diode. [From M. L. Tarng and J. I. Pankove, Passivation of p-n junction in crystalline silicon by amorphous silicon, IEEE Trans. Electron Devices, 1979.]...

See other pages where Trans-passive is mentioned: [Pg.123]    [Pg.287]    [Pg.814]    [Pg.4434]    [Pg.156]    [Pg.151]    [Pg.7]    [Pg.123]    [Pg.287]    [Pg.814]    [Pg.4434]    [Pg.156]    [Pg.151]    [Pg.7]    [Pg.47]    [Pg.415]    [Pg.732]    [Pg.577]    [Pg.161]    [Pg.181]    [Pg.94]    [Pg.166]    [Pg.649]    [Pg.320]    [Pg.190]    [Pg.482]    [Pg.67]    [Pg.168]    [Pg.190]    [Pg.47]    [Pg.52]    [Pg.47]    [Pg.267]    [Pg.286]    [Pg.304]    [Pg.371]    [Pg.295]    [Pg.380]   
See also in sourсe #XX -- [ Pg.6 ]




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