pH effect on the potentiodynamic behaviour of titanium electrodes

Khalil, Munawar; Rahim, M. A. Abdel

doi:10.1002/mawe.19910220707

Cited by 2 publications

(3 citation statements)

References 17 publications

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“…(1) show that Ti anodization in the NaOH solutions are basically different from those found in other electrolytes studied before (acidic sulphate and buffer solution [5]). Two major differences are observed in connection with the voltammogrames in NaOH compared to other electrolytes: ± At one and the same scan rate the current densities of the passivation peaks (the first plateau in Fig.…”

Section: Behaviour Of Titanium Electrode In Naoh Solutionmentioning

confidence: 83%

“…Experiments were carried out in a conventional glass cell that was described elsewhere [5]. The titanium (Koch light 99.9%) working electrodes used were prepared in the same manner as in a previous work [8].…”

Section: Methodsmentioning

confidence: 99%

“…In a previous paper [5], the pH effect on the anodic behaviour of titanium was studied. A comparison was made using the thermodynamic data that revealed the possibility of formation of TiO 2 directly from titanium hydride.…”

Section: Introductionmentioning

confidence: 99%

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An approach to the effect of hydrogen loading on the anodic behaviour of Ti in NaOH solutions

Rahim

Khalil

1999

Mat.-wiss. u. Werkstofftech.

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The voltammetric behaviour of titanium electrode in 0.5 M NaOH solution was investigated. The I‐E curves revealed the presence of a well‐defined O2 evolution peak. The peak current density decreases to a great extent by pre‐loading the metal with hydrogen by cathodic polarization, indicating that pre‐loading the metal with hydrogen suppresses the O2 evolution. The oxidation of hydrogen loaded inside the metal was suggested to be responsible for reducing the O2 evolution peak current density during Ti anodization. The charge consumed during the anodic polarization of Ti, below O2 evolution potential, was used to estimate the anodization coefficient and capacitance measurement was conducted for measuring the dielectric constant of the oxide film. Pre‐loading the metal with hydrogen was found to decrease the oxide film formation rate as well as the dielectric constant.

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Section: Behaviour Of Titanium Electrode In Naoh Solutionmentioning

confidence: 83%

Section: Methodsmentioning

confidence: 99%

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An approach to the effect of hydrogen loading on the anodic behaviour of Ti in NaOH solutions

Rahim

Khalil

1999

Mat.-wiss. u. Werkstofftech.

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Charge transfer reactions across oxide covered Titanium Electrodes

Khalil

1992

Materialwissenschaft Werkst

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The kinetics of the charge transfer process of the ferro-/ferricyanide Redox system on anodically formed titanium oxide layers is studied. The oxides were formed potentiodynamically in borate buffer solutions of pH = 8. Anodic and cathodic Tafel lines were measured at a scan rate of 1.0 mV . s-l. Oxide thickness was measured using capacitance technique at a frequency of 1.0 KHz.The log of the exchange cd, 6 for the Redox system was found to decrease linearly with the oxide thickness in agreement with the lntroduct ionSince the pioneering work of Makrides [l], the study of the kinetics of Redox reactions on anodically formed oxide films on different metals found increasing interest. He measured anodic and cathodic Tafel lines on oxide films formed on Ni, Fe and Ti electrodes. It was early established [2-41, that the exchange cds of a Redox reaction is much smaller on oxide covered electrodes (8 or 9 orders of magnitude) compared to those obtained on "bare" metals. Generally, polarization curves are reliable when changes of film thickness and film composition are avoided [5]. The process was studied later in details on several oxide covered electrodes using different Redox systems [6-121. The development of the theory of electron transfer [13-151 contributed to further understanding of the relation between exchange cd and film thickness. Tunneling of electrons was proposed to explain the results obtained for thin films. The transfer coefficient of the anodic process was smaller than the usual value of 0.5.In an earlier publication, we studied the formation of anodic oxide films onTi electrodes in different media [16]. Mainly Ti02 was found to be formed on the electrodes within a large potential range (-0.6-5.0 V NHE). The stability of the anodic oxide film on Ti, made it possible to study the kinetics of the ferdferrocyanide Redox couple on oxide-covered electrodes, which we report here.Heusler et al. [17] reviewed the theoretical consideration of the theory of electron transfer across semiconductor oxide films. The work presented here is influenced by Heusler's theoretical treatment. it possible to avoid the use of supporting electrolyte. The oxide was formed potentiodynamically until a certain denoted potential in pure borate buffer at pH 8. The use of galvanostatic or potentiostatic technique to form the oxide led to irreproducible Tafel lines for the Redox system. The electrode was transferred from the solution in which it was formed (pH = 8) to the solution which contains equal concentrations of the Redox couple. The solution was Nzdeaerated for 30 min during which the potential was followed as a function of time. Generally steady-state open circuit potentials were established within this period of time.The potential was then scanned in the anodic and then in the cathodic direction using a scan rate of 1 mV . s-l. ExperimentalA simple and approximate method was used to estimate the oxide thickness using the capacitance measurements. This was performed at a frequency of 1.0 KHz and oxide thickness was calculate...

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pH effect on the potentiodynamic behaviour of titanium electrodes

Cited by 2 publications

References 17 publications

An approach to the effect of hydrogen loading on the anodic behaviour of Ti in NaOH solutions

An approach to the effect of hydrogen loading on the anodic behaviour of Ti in NaOH solutions

Charge transfer reactions across oxide covered Titanium Electrodes

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