Crystallization of anodic titania on titanium and its alloys

ISE member 2The present study reveals the formation of porous anodic films on titanium at an increased growth rate in hot phosphate/glycerol electrolyte by reducing the water content. A porous titanium oxide film of 12 µm thickness, with a relatively low content of phosphorus species, is developed after anodizing at 5 V for 3.6 ks in 0.6 mol dm -3 K 2 HPO 4 +0.2 mol dm -3 K 3 PO 4 /glycerol electrolyte containing only 0.04%water at 433 K. The growth efficiency is reduced by increasing the formation voltage to 20 V, due to formation of crystalline oxide, which induces gas generation during anodizing. The film formed at 20 V consists of two layers, with an increased concentration of phosphorus species in the inner layer. The outer layer, comprising approximately 25% of the film thickness, is developed at low formation voltages, of less than 10 V, during the initial anodizing at a constant current density of 250 A m -2. The pore diameter is not significantly dependent upon the formation voltage, being ~10 nm.

show abstract

“…The formation of crystalline oxide induces gas generation during anodizing [22][23][24], such that the efficiency of film growth is reduced.…”

Section: Resultsmentioning

confidence: 99%

“…The gas evolution is associated with the development of crystalline oxide in growing anodic titanium oxide [23,24]. Thus, inhibition of crystalline oxide formation is essential to form thick porous anodic titanium oxide in hot phosphate/glycerol electrolyte at an improved efficiency.…”

Section: Introductionmentioning

confidence: 99%

Formation of porous anodic titanium oxide films in hot phosphate/glycerol electrolyte

Habazaki

Teraoka

Aoki

et al. 2010

Electrochimica Acta

Self Cite

View full text Add to dashboard Cite

show abstract

“…It should be worth mentioning that the anodic oxide films on the Zr-Al alloys containing up to 16 at% aluminum are two layers with a thin amorphous outer layer. The relative permittivity of th [6]e amorphous oxide must be different from the inner crystalline oxide.…”

Section: Impedance Measurements and Dielectric Propertiesmentioning

confidence: 99%

“…Titanium forms an amorphous anodic oxide at low formation voltages, but an amorphous-to-crystalline transition occurs above ~5 V [4]. After the transition, the film growth proceeds at reduced efficiency due to oxygen gas generation within growing anodic oxide film [5,6]. Thus, the films contain always cracks, voids and blisters.…”

Section: Introductionmentioning

confidence: 99%

Formation and dielectric properties of anodic oxide films on Zr–Al alloys

Koyama

Aoki

Nagata

et al. 2010

J Solid State Electrochem

View full text Add to dashboard Cite

Zr-Al alloys containing up to 26 at.% aluminum, prepared by magnetron sputtering, have been anodized in 0.1 mol dm -3 ammonium pentaborate electrolyte, and the structure and dielectric properties of the resultant anodic oxide films have been examined by grazing incidence X-ray diffraction, transmission electron microscopy, Rutherford backscattering spectroscopy and AC impedance spectroscopy. The anodic oxide film formed on zirconium consists of monoclinic and tetragonal ZrO 2 with the former being a major phase. Two-layered anodic oxide films, comprising an outer thin amorphous layer and an inner main layer of crystalline tetragonal ZrO 2 phase, are formed on the Zr-Al alloys containing 5 to 16 at.% aluminum. Further increase in the aluminum content to 26 at.% results in the formation of amorphous oxide layer throughout the thickness. The anodic oxide films becomes thin with increasing aluminum content, while the relative permittivity of anodic oxide shows a maximum at the aluminum content of 11 at.%. Due to major contribution of permittivity enhancement, the maximum capacitance of the anodic oxide films is obtained on the Zr-11 at.% Al alloy, being 1.7 times than on zirconium at the formation voltage of 100 V.

show abstract

“…The crystallisation of amorphous anodic titania can occur on titanium at voltages of less than 10 V in aqueous electrolyte at ambient temperature [12]. The crystalline oxide is developed in the inner film material, which is formed at the metal/film interface by inward migration of oxygen species [13]. In the present anodizing conditions, the crystallisation and associated oxygen generation may occur more readily due to the elevated temperature.…”

Section: Discussionmentioning

confidence: 92%

Formation of porous anodic films on Ti–Si alloys in hot phosphate-glycerol electrolyte

Habazaki

Oikawa

Fushimi

et al. 2007

Electrochimica Acta

Self Cite

View full text Add to dashboard Cite

Porous anodic films, with pore size of ~10 nm, have been developed by anodizing of magnetron sputtered Ti-25 at% Si alloy at constant formation voltages in glycerol electrolyte containing dibasic potassium phosphate at 433 K. The films, of amorphous structure, contain titanium and silicon species, as units of TiO 2 and SiO 2 , throughout the film thicknesses, with negligible amounts of phosphorus species. The silicon is enriched in the film relative to the composition of the alloy, the level of enrichment suggesting that anion migration is increased in comparison with amorphous film growth at ambient temperature. In contrast to the behaviour of the alloy, essentially barrier films were formed on commercially pure titanium in the glycerol electrolyte, when a main anodic reaction was generation of oxygen, which was probably promoted by the development of anatase.

show abstract

Crystallization of anodic titania on titanium and its alloys

Cited by 230 publications

References 30 publications

Formation of porous anodic titanium oxide films in hot phosphate/glycerol electrolyte

Formation of porous anodic titanium oxide films in hot phosphate/glycerol electrolyte

Formation and dielectric properties of anodic oxide films on Zr–Al alloys

Formation of porous anodic films on Ti–Si alloys in hot phosphate-glycerol electrolyte

Contact Info

Product

Resources

About