Raman spectroscopy of titanium dioxide layers

Felske, A.; Plieth, W.

doi:10.1016/0013-4686(89)80012-x

Cited by 74 publications

(32 citation statements)

References 5 publications

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“…30 The other indicative Raman active peaks for anatase TiO2 at 402 cm -1 (B1g), 523 cm -1 (A1g or B1g), and 638 cm -1 (Eg) 30 become apparent in the spectrum for a sample heated to 600 °C. 31 Two further peaks also appear in the Raman spectra of 600 and 700 °C heated samples, attributed to the E2g optical mode (broad, 1600 cm -1 ) and D-band (broad, 1360 cm -1 ) modes often observed in carbon-based materials. 32 Since their emergence is concurrent with the first crystalline phases in the XRD (Figure 3), it is concluded there is combustion of the organic matrix.…”

Section: Resultsmentioning

confidence: 93%

Synthesis of Barium Titanate Using Deep Eutectic Solvents

et al. 2016

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Novel synthetic routes to prepare functional oxides at lower temperatures are an increasingly important area of research. Many of these synthetic routes, however, use water as the solvent and rely on dissolution of the precursors, precluding their use with, for example, titanates. Here we present a low cost solvent system as a means to rapidly create phase-pure ferroelectric barium titanate using a choline chloride-malonic acid deep eutectic solvent. This solvent is compatible with alkoxide precursors and allows for the rapid synthesis of nanoscale barium titanate powders at 950 °C. The phase and morphology were determined, along with investigation of the synthetic pathway, with the reaction proceeding via BaCl2 and TiO2 intermediates. The powders were also used to create sintered ceramics, which exhibit a permittivity maximum corresponding to a tetragonal-cubic transition at 112 °C, as opposed to the more conventional temperature of ~ 120 °C. The lower-thanexpected value for the ferro-to para-electric phase transition is likely due to undetectable levels of contaminants.

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Section: Resultsmentioning

confidence: 93%

Synthesis of Barium Titanate Using Deep Eutectic Solvents

et al. 2016

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“…These observations are consistent with the Pourbaix diagram for the metal [7] which shows that the oxide TiOx is the only stable reaction product under the conditions of pH that can be encountered in vivo. The actual composition of the passivating oxide has not been firmly established, although most investigators agree that the main constituent of the film displays the TiO2 stoichiometry [8][9][10][11][12][13][14][15][16], accompanied by some Ti203 [8, 14, 163. After implantation of titanium in the human body, the metal oxide layer undergoes some changes, namely thickening of the passivating film and some stoichiometric changes• Phosphorus, calcium and silicon are incorporated into the oxide surface from the local environment, and some metal dissolution also occurs [17][18][19][20]. Thus, despite the adherence of the film to its metal substrate, and its ability to reform readily when damaged, titanium has occasionally been observed in tissue adjacent to an implant prosthesis [17 22].…”

Section: Introductionmentioning

confidence: 99%

A preliminary investigation into the microscopic depassivation of passive titanium implant materials in vitro

Souto

Burstein

1996

J Mater Sci: Mater Med

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A sensitive electrochemical technique has been used to examine the passive state of titanium-based materials in Ringer's physiological solution. At ambient temperature, the alloy Ti-6AI-4V shows transient microscopic breakdown of the passive state induced by the presence of chloride ions, and enhanced by increased acidity. These breakdown events involve highly localized depassivation of the passive surface followed by repassivation. Under similar experimental conditions no breakdown of passive titanium was detected.

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“…Improvement of corrosion resistance and sometimes introducing the bioactivity of titanium and its alloys is achieved by different methods resulting in change in crystallinity degree, contribution of various crystalline forms of titania (morphology), structure and thickness of the oxide layer [16]. The formed oxides may be amorphous or crystalline, depending on anodic potential value and electrolyte [17,18]. The oxide film on pure Ti is composed of mainly TiO 2 -either rutile or anatase, seldom brookite.…”

Section: Oxidationmentioning

confidence: 99%

“…The treatment of Ti alloys is carried out at constant or slowly changing values of current below breakdown potential in sulphuric, phosphoric, acetic, chromic acids and sometimes in alkali, resulting in adjustments of thickness, chemical composition and structure of layers [17,26]. The constant current or constant voltage techniques with an use of fluoric acid allow to obtain oxide layers composed of nanometric crystallites or amorphous islands [27][28][29]. The micro spark technique makes it possible to incorporate into the oxide layer the ions which can promote adhesion of osteoblasts, as calcium, phosphorous or oxygen ions [29].…”

Section: Oxidationmentioning

confidence: 99%

Biocompatibility and Bioactivity of Load-Bearing Metallic Implants

Zieliński¹,

Sobieszczyk²,

Seramak³

et al. 2010

Advances in Materials Sciences

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The main objective of here presented research is to develop the titanium (Ti) alloy base composite materials possessing better biocompatibility, longer lifetime and bioactivity behaviour for load-bearing implants, e.g. hip joint and knee joint endoprosthesis. The development of such materials is performed through: modeling the material behaviour in biological environment in long time and developing of new procedures for such evaluation; obtaining of a Ti alloy with designed porosity; developing of an oxidation technology resulting in high corrosion resistance and bioactivity; developing of technologies for hydroxyapatite (HA) deposition aimed at composite bioactive coatings; developing of technologies of precipitation of the biodegradable core material placed within the pores. The examinations of degradation of Ti implants are carried out in order to recognize the sources of both early allergies and inflammation, and of long term degradation. The theoretical assessment of corrosion is made assuming three processes: electrochemical dissolution through imperfections of the anodic oxide layer, diffusion of metallic ions through the oxide layer, and dissolution of oxides themselves. In order to increase the biocompatibility, the toxic elements, aluminium (Al) and vanadium (V) are eliminated. The experiments have shown that titanium -zirconium -niobium (Ti-Zr-Nb) alloy may be a such a material which can also be prepared by both powder metallurgy (P/M) technique and selective laser melting. The porous (scaffold) Ti-Zr-Nb alloy is now obtained by powder metallurgy, classical and with space holders used before melting and decomposed, or remained during melting and removed by subsequent water dissolution. The oxidation of porous materials is performed either by electrochemical technique in special electrolytes or by chemical and/or hydrothermal method in order to obtain the optimal oxide layer well adjacent to an interface, preventing the base metal against corrosion and bioactive because of its nanotubular structure, permitting injection of some species into the pores. The Ca, O and N ion implantation or deposition of zirconia sublayers may be used to increase the biocompatibility, bioactivity and corrosion resistance. The HA coating obtained by either electrophoretic, biomimetic or by sol-gel deposition should result in gradient structure similar to bone structure, possessing high adhesion strength. The core material of the porous material should result in a biodegradable material, allowing slower dissolution followed by stepwise growth of bone tissue and angiogenesis, preventing local inflammation processes, sustaining the mechanical strength close to that of non-porous material.

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Raman spectroscopy of titanium dioxide layers

Cited by 74 publications

References 5 publications

Synthesis of Barium Titanate Using Deep Eutectic Solvents

Synthesis of Barium Titanate Using Deep Eutectic Solvents

A preliminary investigation into the microscopic depassivation of passive titanium implant materials in vitro

Biocompatibility and Bioactivity of Load-Bearing Metallic Implants

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