Electrolytic breakdown crystallization of anodic oxide films on A1, Ta and Ti

Yahalom, J.; Zahavi, J.

doi:10.1016/0013-4686(70)80064-0

Cited by 152 publications

(71 citation statements)

References 8 publications

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“…At potentials more positive than 5.5V, a craterconglomerate morphology with a single-crater diameter of about 3 ~m is observed. Such a crater-like morphology was also reported by Yahalom et al (11). At potentials more positive than 7.5V, the surface becomes rough, with a ripple-like appearance.…”

Section: Film Breakdown--thesupporting

confidence: 85%

“…From the large value of thickness-to-charge ratio and the small refractive index, it is suggested that the anodic oxide film contains some amount of water. Yahalom et al (11) and Blondeau et al (27) have observed electron diffraction patterns corresponding to anatase TiO2 for the anodic films formed at potentials more positive than 50V, where the film breakdown takes place. Blondeau et al (27) have also observed a quasiamorphous structure for the anodic oxide film formed at more negative potentials.…”

Section: Film Breakdown--thementioning

confidence: 99%

“…McAleer et al (10) investigated by optical interferometry the breakdown phenomenon during potentiostatic anodization of titanium at high scan rate and found that both oxygen evolution and rapid film thickening take place when the film breaks down. Yahalom et al (11) investigated by use of TEM the anodic oxide film of titanium stripped from the metal substrate and detected the anatase type of diffraction pattern for the anodized oxide film subjected to breakdown and crystallization. Dyer et al (12) employed ellipsometry to study the film growth on titanium during galvanostatic oxidation and obtained the relationship between film thickness, cell voltage, weight gain, and anodic charge passed.…”

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confidence: 99%

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Ellipsometric Study of Anodic Oxide Films on Titanium in Hydrochloric Acid, Sulfuric Acid, and Phosphate Solution

Ohtsuka

Masuda

Satô

1985

J. Electrochem. Soc.

164

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The anodic oxide film on titanium has been studied by ellipsometry and SEM observation. Ex situ multiple-angleof-incidence and in situ ellipsome_tric measurements allow the complex refractive index to be estimated at n = 2.3-2.9i for the titanium substrate and at n = 2.1-0.03i for the anodic oxide film at wavelength 546.1 nm. The anodic oxide film thickness increases linearly with potential in a range from -0.55 to 7.5V (RHE) at the rate of 2.8 nm V -' in phosphate solutions ofpH 1.6-12.1, 2.5 nm V-' in 0.1M HC1 solution, and 2.4 nm V-' in 0.1M H2SO4 solution. At potentials more positive than 7.5V, the film breaks down, leading to the formation of a thick oxide film probably due to an increased ionic current through the breakdown sites. The film composition is estimated to be TiO2(H20)l.4 or TiO0.6(OH)2.8, which suggests the presence of hydroxyl bridge in its bonding structure.

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Section: Film Breakdown--thesupporting

confidence: 85%

Section: Film Breakdown--thementioning

confidence: 99%

mentioning

confidence: 99%

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Ellipsometric Study of Anodic Oxide Films on Titanium in Hydrochloric Acid, Sulfuric Acid, and Phosphate Solution

Ohtsuka

Masuda

Satô

1985

J. Electrochem. Soc.

164

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“…Hence, a crystal structure was formed (e.g., α-Al 2 O 3 or γ-Al 2 O 3 ), leading to a resistance increase in the original defective district. 16 The current preferentially passed through a defective district with relatively low resistance, leading to the formation of a new microdischarge (R 2 channel) at time T n+1 ( Figure 4b) and a nonuniform micropore distribution. The micropores in areas A and B possibly originated from the former discharge and new discharge, respectively ( Figure 4c).…”

Section: Qualitative Theoretical Analysis Of Self-organization In Maomentioning

confidence: 99%

Self-Organization Kinetics of Microarc Oxidation: Nonequilibrium-State Electrode Reaction Kinetics

Jiang

Liu

et al. 2016

J. Electrochem. Soc.

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Here, we present a new method for studying and gaining new insights into microarc oxidation (MAO) and its corresponding nonequilibrium-state electrode reaction kinetics. We observed that the fundamental condition of microdischarge formation was the resistance nonequilibrium in the oxide film caused by the existence of a defective region. Specifically, the current always first passed through a path with the lowest resistance. After the first discharge, a ceramic phase (e.g., α-Al2O3) was formed, which changed the conductive properties of the defective region, and the resistance in the defective region was subsequently increased, which sent feedback to the next current distribution. This fundamental and inherent law rendered controlling and predicting the microarc system kinetics by the external environment difficult. Therefore, we developed a microarc algorithm and proposed a feedback coefficient k, which determines whether the anode current distribution is inclined to or deviates from the equilibrium state. Finally, we analyzed the k-frequency relationship and used frequency to experimentally describe various kinetic behaviors of MAO.

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“…At such high voltages, the process will lead to increased gas evolution and sparking. During anodic oxidation of titanium metal, oxygen gas evolution is usually observed, which contributes to reduce the current efficiency of the growth process [6][7].…”

Section: Mechanism Of Anodic Oxidation Of Titaniummentioning

confidence: 99%

Electrochemical surface modification of titanium in dentistry

2009

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Titanium and its alloys have good biocompatibility with body cells and tissues and are widely used for implant applications. However, clinical procedures place more stringent and tough requirements on the titanium surface necessitating artificial surface treatments. Among the many methods of titanium surface modification, electrochemical techniques are simple and cheap. Anodic oxidation is the anodic electrochemical technique while electrophoretic and cathodic depositions are the cathodic electrochemical techniques. By anodic oxidation it is possible to obtain desired roughness, porosity and chemical composition of the oxide. Anodic oxidation at high voltages can improve the crystallinity of the oxide. The chief advantage of this technique is doping of the coating of the bath constituents and incorporation of these elements improves the properties of the oxide. Electrophoretic deposition uses hydroxyapatite (HA) powders dispersed in a suitable solvent at a particular pH. Under these operating conditions these particles acquire positive charge and coatings are obtained on the cathodic titanium by applying an external electric field. These coatings require a post-sintering treatment to improve the coating properties. Cathodic deposition is another type of electrochemical method where HA is formed in situ from an electrolyte containing calcium and phosphate ions. It is also possible to alter structure and/or chemistry of the obtained deposit. Nano-grained HA has higher surface energy and greater biological activity and therefore emphasis is being laid to produce these coatings by cathodic deposition.

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Electrolytic breakdown crystallization of anodic oxide films on A1, Ta and Ti

Cited by 152 publications

References 8 publications

Ellipsometric Study of Anodic Oxide Films on Titanium in Hydrochloric Acid, Sulfuric Acid, and Phosphate Solution

Ellipsometric Study of Anodic Oxide Films on Titanium in Hydrochloric Acid, Sulfuric Acid, and Phosphate Solution

Self-Organization Kinetics of Microarc Oxidation: Nonequilibrium-State Electrode Reaction Kinetics

Electrochemical surface modification of titanium in dentistry

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