Numerical modelling of anodization reaction kinetics for TiO2 nanotubular-film growth in NH4F-based electrolytes

Suliali, Nyasha J.; Mbulanga, C.M.; Goosen, William E.; Betz, Richard; Botha, J.R.

doi:10.1016/j.electacta.2020.135791

Cited by 25 publications

(17 citation statements)

References 42 publications

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“…has been researched for quite a long time as one of hot topics, the formation mechanism of it is still not very clear. [15][16][17][18][19][20] For the lack of research on the formation mechanism, a large number of experiments should be conducted to summarized experience when developing and improving the preparation technology of nanotubes, so it is significant to clarify the formation mechanism of nanotubes in order to accurately control its morphology. After years of research and discussion, several mainstream theories have been formed in the academic community today.…”

Section: Introductionmentioning

confidence: 99%

A review: research progress on the formation mechanism of porous anodic oxides

Gong

et al. 2022

Nanoscale Adv.

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Section: Introductionmentioning

confidence: 99%

A review: research progress on the formation mechanism of porous anodic oxides

Gong

et al. 2022

Nanoscale Adv.

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“…This indicates that the increased fluoride concentration in electrolyte leads to the increased content of fluoride in the surface films due to its ability to migrate and intercalate into the oxide films during the anodizing process 35 . Suliali et al 36 reported that the fluoride ions in electrolyte can attack titanium ions and hydroxide/oxide film to form the most stable fluoride complex of titanium 36,44 :

{Ti}^{4 +} ((), aq) goodbreak+ {6F}^{-} ((), aq) ➔ {[{TiF}_{6}]}^{2 -} ((), aq)

Ti {(OH)}_{4} ((), s) goodbreak+ {6F}^{-} ((), aq) ➔ {[{TiF}_{6}]}^{2 -} ((), aq) goodbreak+ {4OH}^{-} ((), aq)

{TiO}_{2} ((), s) goodbreak+ {4H}^{+} ((), aq) goodbreak+ {6F}^{-} ((), aq) ➔ {[{TiF}_{6}]}^{2 -} ((), aq) goodbreak+ {2H}_{2} normalO ((), l)

…”

Section: Resultsmentioning

confidence: 99%

Effect of fluoride and hydroxyl group on bioactivity of the anodized films prepared by two‐step anodization at low current density

Saenrang

Kashima

2022

Surface & Interface Analysis

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Titanium and its alloys are promising dental implant materials. In order to improve the bioactivity of the anodized films, the two‐step anodization was performed to produce the films. The steps were performed at 0.2 mA/cm2 for 30 min in electrolytes containing H3PO4/C2H5OH and H3PO4/C2H5OH/NH4F, respectively. The anodized films were soaked in a simulated body fluid (SBF). The effects of surface roughness, hydroxyl groups, fluoride, and hydrophilicity groups on the bioactivity were investigated and were found on the anodized films formed under two‐step anodization using 1 M H3PO4 + 80% V/V C2H5OH + 0.75 wt% NH4F. The bioactivity evaluation showed that the combination of two‐step anodization in NH4F as an electrolyte induced a formation of apatite on the anodized films. The surface roughness, hydroxyl groups, and fluoride formed on the hydrophilic anodized films are found to be responsible for the rapid formation of hydroxyapatite during SBF soaking. This will be useful in various biomedical applications especially in dental implant procedures.

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“…20 Even though many facts deny the FAD theory and dissolution equilibrium theory, [32][33][34][35][36][37][38][39][40][41][42][43] many researchers still ambiguously explain various experimental phenomena by applying the FAD and dissolution equilibrium theories. [44][45][46][47] The second model is an oxygen bubble model based on the viscous ow model [48][49][50] and the electronic current theory. [51][52][53][54] The growth manner of the nanotubes is the viscous ow of the barrier oxide layer around the oxygen bubble model to promote the growth of the nanotubes.…”

Section: Introductionmentioning

confidence: 99%

“…Meanwhile, others accept the viscous ow model, but deny the electronic current and oxygen bubble mold, resulting in the vague dynamics of both the FAD and FAF models and the eldassisted effect. [44][45][46][47][48][49][50][51] Compared with the above two models, the growth kinetics of eld-assisted dissolution equilibrium theory has been ambiguous for decades. [45][46][47][48][49][50][51] The physical meanings of FAD and FAF are always unclear.…”

Section: Introductionmentioning

confidence: 99%