Anodization of molybdenum in glycol-borate electrolyte— A peculiar kinetics of insulating film formation

Ikonopisov, S.

doi:10.1016/0300-9416(73)90037-0

Cited by 11 publications

(2 citation statements)

References 25 publications

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“…Lavrenko and Pen'kov (21) claim to have anodized Mo in saturated boric acid at up to 200V. We could not reproduce their results, while Ikonopisov (22) suggests that the high voltage drop observed by Lavrenko and Pen'kov may have been due to the high resistance diaphragm between the electrodes. The first successful results are accordingly those of the present authors with an acetic acid-based electrolyte (5) and of Ikonopisov with a glycol-borate electrolyte (22).…”

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confidence: 63%

Some Aspects of the Anodic Oxidation of V, Mo, and W

Arora

Kelly

1977

J. Electrochem. Soc.

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V, Mo, and W can be readily anodized in an electrolyte consisting of acetic acid, 0.02MNa2B4O7·10H2O , and 1.0M additional water as proposed orginally by Keil and Salomon for V. The resulting films, when formed in the presence of air, are duplex, being crystalline and of lower stoichiometry near the metal‐film interface but having stoichiometries near V2O5 , MoO3 , and WO3 beyond the metal‐film interface. The films formed on V and Mo are subject to significant dissolution such that time‐independent dissolution currents false(i2false) of 0.11 and 0.04 mA/cm2 can be inferred; with W, by contrast, the dissolution current was only ∼0.001 mA/cm2. The electronic currents false(i2false) are estimated to be 0.09 mA/cm2 for V, 0.12 mA/cm2 for Mo, and 0.03 mA/cm2 for W, and the constant‐current efficiency follows as being given by the relation η=false(I−i2−i3false)/I , where I is the total applied current. The efficiencies for V and Mo thus lie in the interval 0.60–0.92 for 0.5≤I≤2.0 normalmA/cm2 , whereas W shows essentially unit current efficiency. Efficiencies are also deduced for conditions of mixed constant current and constant voltage. That of V is unusually low, as is to be expected for such conditions, whereas that of Mo is unusually high, suggesting that the average stoichiometry of the film is measurably less than MoO3 . Again W shows essentially unit efficiency.

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confidence: 63%

Some Aspects of the Anodic Oxidation of V, Mo, and W

Arora

Kelly

1977

J. Electrochem. Soc.

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“…Induction periods are observed during anodizing under certain conditions [16] and their duration decreases with increasing current density according to a power law [17]. There are suggestions in the literature that low-impedance semiconductor layers form during induction periods in aqueous solutions of phosphoric acid [18] analogous to the induction periods during anodizing of molybdenum [19]. According to the voltammetric and ellipsometric data, the anodic behavior is a stepwise electroformation of different antimony species, with Sb 2 O 3 being the final product [20].…”

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confidence: 99%

Change of the antimony anodizing kinetics by coating the electrode with a thin film

Lilov,

Lilova,

Nedev

et al. 2023

JCTM

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The present research work is dedicated on the processes kinetics description of the antimony anodization in potassium phosphate (K 3 PO 4 ) aqueous solutions. The data have shown that the slope of the kinetic curves is dependent on the phosphate solution concentration. Besides, their mathematic approximation has revealed occurrence of a critical phosphate solution concentration of 0.11 mol dm -3 . At this concentration, the slope of the kinetic curve tends to zero. Above this critical concentration, induction periods occur during the anodization. Additional experiments were performed with thin Sb 2 O 3 layers preliminary deposited in vacuum. This approach has enabled to define the impact of such layers on the kinetic behavior during the anodization process. The results have shown that various stages of the process could be skipped. The final data analysis has confirmed the suggestion that the induction periods and voltage variations during the anodization process are caused by the formation of a thin Sb 2 O 3 film, whose dielectric properties change with the film thickness increment.

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