Influence of Molybdenum on the Pitting Corrosion of Aluminum Films

Abstract

not Available.

Corrosion Inhibition of Aluminum Alloy 2024-T3 by Sodium Molybdate

“…According to Hu et al, 42 the structure of surface molybdenum oxides present on Al 2 O 3 under ambient conditions consists of polymeric species (Mo 7 O 24 6− and Mo 8 O 26 4− ) at high Mo loadings. In addition, Spevack et al found evidence of multivalent (Mo(IV), Mo(V), and Mo(VI)) species within molybdenum oxide films supported on alumina and graphite.…”

“…[21][22][23] The impact of molybdate on the corrosion resistance of aluminum has been explored extensively in the literature. 21,[24][25][26][27][28][29][30][31][32][33][34] Molybdate improves the pitting resistance of aluminum and its alloys by increasing the pitting potential to more noble values with respect to the opencircuit potential. 28 However, the extent of inhibition is highly dependent on the ratio of molybdate to chloride ion concentration.…”

Electrochemical Behavior and Surface Chemistry of Nonequilibrium Aluminum Alloys: Passivity Mechanism and Fabrication Methods

“…Several different mechanisms have been proposed to explain the passivity of stainless aluminum alloys, including electrostatic repulsion of Cl" by oxidized solute atoms [1][2][3], formation of an oxidized solute barrier layer [3,4], blockage of Cl" transport through the passive film [22], stabilization of the passive film oxide structure [6], replacement of oxidized Al in the passive film by oxidized solute to form a more stable oxide [28,29], reduction of the critical pH for pit propagation [17][18][19][20], and reduction in C1-adsorption due to pHpzc changes [11][12][13][14][15]. Additionally, Macdonald and coworkers [34,35] studying Mo-and W-containing stainless steels have proposed a solutevacancy interaction model (SVIM).…”

“…The SRIM explains why mechanisms involving properties of an oxidized solute passive film, such as barrier layer formation [1][2][3][4]22,28,29], pHpzc reduction [11][12][13][14][15], and solubility reduction in low-pH environments [17][18][19][20], can appear to account for the enhanced passivity of these alloys despite the fact that the passive film is at least half oxidized or hydrated aluminum and can be almost entirely oxidized or hydrated aluminum, depending on the alloy system and the polarization conditions. The important factor is the solute's localized concentration at the interphase and in occluded cells, not the overall concentration of the solute in the passive film.…”

“…In the last several years, supersaturated aluminum alloys with Mo, Cr, Ta, W, Zr, Nb, Zn, V, Cu, Ti, and Si have been produced by several groups using rapid solidification or other nonequilibrium methods , such as sputter deposition [1][2][3][4][5][6][7][8][9][10][16][17][18][19][20][21][22][23][28][29][30][31][32][33], ion implantation [11][12][13][14][15]24,25], melt spinning [27], and vapor deposition [26,33]. Several alloys have shown significant improvements in passivity in chloridecontaining environments.…”