Morphology and Electronic Structures of Calcium Phosphate Coated Titanium Dioxide Nanotubes

2011 ◽  
Vol 1352 ◽  
Author(s):  
Lijia Liu ◽  
Sun Kim ◽  
Jeffrey Chan ◽  
Tsun-Kong Sham
Keyword(s):  
Titanium Dioxide ◽  
Calcium Hydroxyapatite ◽  
Electrochemical Anodization ◽  
Edge Structure ◽  
Titanium Dioxide Nanotubes ◽  
Coating Efficiency ◽  
Different Temperatures ◽  
Crystal Phases ◽  
X Ray Absorption ◽  
Better Than

ABSTRACTTitanium dioxide nanotubes (TiO2-NT) have been synthesized via an electrochemical anodization strategy followed by calcination under different temperatures to form TiO2 nanostructures of anatase and rutile crystal phases. The nanotube-on-Ti structure is further used as a substrate for calcium hydroxyapatite (HAp) coating. The effect of TiO2 morphology and crystal phases (i.e. amorphous, anatase and rutile) on the coating efficiency of HAp has been investigated in comparison with HAp coating on bare Ti metal. The HAp coated TiO2-NT have been studied using X-ray absorption near-edge structure (XANES) at the Ti K- and Ca K-edge. The results show that TiO2 of amorphous and anatase phases are of comparably good performance for HAp crystallization, and both are better than rutile TiO2, while HAp is hardly found on bare Ti. The implications of the findings are discussed.

Effect of TiO2 crystal form on the denitration performance of Ce–W–Ti catalyst

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Xue Bian ◽  
Yuntao Yu ◽  
Nana Hao ◽  
Wenyuan Wu
Keyword(s):  
Titanium Dioxide ◽  
Mixed Crystal ◽  
Surface Acidity ◽  
High Surface ◽  
Crystal Form ◽  
Large Specific Surface Area ◽  
Metatitanic Acid ◽  
Pure Phase ◽  
Crystal Phases ◽  
Better Than

Abstract Titanium dioxide supports, which were prepared by roasting metatitanic acid under different conditions, were used to prepare a series of Ce–W–Ti catalysts. The structure and denitration properties of the catalyst were studied. The results showed that TiO2 had different crystal types (mixed crystal phases with different proportions of anatase and rutile) under different roasting conditions, and the denitration efficiency of mixed crystal was better than that of pure phase TiO2. Ce–W/200 °C-1 hTiO2 catalyst exhibited a prominent NO conversion rate, and it can reach higher than 90% at a temperature range from 250 to 500°C. The large specific surface area, low content of rutile TiO2 in the support, high content of chemical adsorbed oxygen and high surface acidity were favorable to denitration performance of Ce–W–Ti catalyst.

Studies on ZDDP Anti-Wear Films Formed Under the Different Conditions by XANES Spectroscopy, Atomic Force Microscopy and 31P NMR

2007 ◽  
Author(s):  
Yue-Rong Li ◽  
Gavin Pereira ◽  
Masoud Kasrai ◽  
Peter R. Norton
Keyword(s):  
Atomic Force Microscopy ◽  
31P Nmr ◽  
Xanes Spectroscopy ◽  
Edge Structure ◽  
Base Oil ◽  
Force Microscopy ◽  
Atomic Force ◽  
Variable Chemical ◽  
Different Temperatures ◽  
X Ray Absorption

Antiwear (AW) films, generated from a mineral base oil containing zinc dialkyl dithiophosphate (ZDDP) additive, were extensively studied. These films were formed at various conditions such as different temperatures, various loads and rubbing times. The surface morphology of these films was investigated using atomic force microscopy (AFM) and the surface roughness of these films has been calculated from the images. X-ray absorption near edge structure (XANES) spectroscopy has been used to characterize the chemistry of these films. The intensity of phosphorus K-edge was also used to monitor the thickness of these films. Phosphorus L-edge spectra show that these films have slightly variable chemical natures. 31P Nuclear magnetic resonance (31P NMR) was used to study the ZDDP components in the residue oils. The spectra show that the primary and secondary ZDDP decompose quite differently at the various conditions. Tribological characteristics of these AW films were probed by measuring the coefficients of friction and the wear scar width of the counter faces.

Ab Initio XAFS and XANES Standards

1993 ◽  
Vol 307 ◽  
Author(s):  
J. J. Rehr ◽  
S. I. Zabinsky ◽  
R. C. Albers
Keyword(s):  
Fine Structure ◽  
Ab Initio ◽  
Multiple Scattering ◽  
State Of The Art ◽  
Experimental Measurements ◽  
Edge Structure ◽  
X Ray ◽  
Coordination Numbers ◽  
X Ray Absorption ◽  
Better Than

ABSTRACTAb initio x-ray-absorption fine structure (XAFS) and x-ray-absorption near edge structure (XANES) standards are developed for molecules and solids. These standard XAFS spectra are obtained from ab initio XAFS calculations, using an automated code, FEFF, which we have extended to include multiple-scattering (MS) and XANES calculations. Our treatment is based on state-of-the-art curved-wave MS theory. Sample results are presented and compared with experiment. We find that these theoretical standards are comparable with experimental measurements, yielding distance determinations better than 0.02 Å and coordination numbers better than 20%. Our approach also gives a new MS interpretation of the σ* shape-resonances in XANES.

Rutile nanotubes by electrochemical anodization

RSC Advances ◽  
2016 ◽  
Vol 6 (78) ◽  
pp. 74510-74514 ◽  
Author(s):  
Rangasamy Savitha ◽  
Ravikrishna Raghunathan ◽  
Raghuram Chetty
Keyword(s):  
Titanium Dioxide ◽  
Annealing Temperature ◽  
Electrochemical Anodization ◽  
Powder Form ◽  
Titanium Dioxide Nanotubes ◽  
Rutile Titanium Dioxide

We present a facile method to synthesize rutile titanium dioxide nanotubes (R-TiNT), directly in powder form through rapid breakdown electrochemical anodization by modifying the post anodization processing and annealing temperature.

scholarly journals Structural Evolution of MoO3 Thin Films Deposited on Copper Substrates upon Annealing: An X-ray Absorption Spectroscopy Study

2019 ◽  
Vol 4 (2) ◽  
pp. 41 ◽  
Author(s):  
Macis ◽  
Rezvani ◽  
Davoli ◽  
Cibin ◽  
Spataro ◽  
...  
Keyword(s):  
Thin Films ◽  
Absorption Spectroscopy ◽  
Structural Changes ◽  
Structural Evolution ◽  
Ex Situ ◽  
Edge Structure ◽  
X Ray ◽  
High Gradients ◽  
Different Temperatures ◽  
X Ray Absorption

Structural changes of MoO3 thin films deposited on thick copper substrates upon annealing at different temperatures were investigated via ex situ X-Ray Absorption Spectroscopy (XAS). From the analysis of the X-ray Absorption Near-Edge Structure (XANES) pre-edge and Extended X-ray Absorption Fine Structure (EXAFS), we show the dynamics of the structural order and of the valence state. As-deposited films were mainly disordered, and ordering phenomena did not occur for annealing temperatures up to 300 °C. At ~350 °C, a dominant α-MoO3 crystalline phase started to emerge, and XAS spectra ruled out the formation of a molybdenum dioxide phase. A further increase of the annealing temperature to ~500 °C resulted in a complex phase transformation with a concurrent reduction of Mo6+ ions to Mo4+. These original results suggest the possibility of using MoO3 as a hard, protective, transparent, and conductive material in different technologies, such as accelerating copper-based devices, to reduce damage at high gradients.

scholarly journals The microstructure and mechanical properties of titanium dioxide nanotubes synthesized in the fluoride-based electrolyte

10.30544/336 ◽  
2018 ◽  
Vol 24 (2) ◽  
pp. 83-92
Author(s):  
Ying Pio Lim ◽  
Wei Hong Yeo
Keyword(s):  
Mechanical Properties ◽  
Titanium Dioxide ◽  
Wall Thickness ◽  
Hardness Test ◽  
Orthopedic Implants ◽  
Honeycomb Structure ◽  
Electrochemical Anodization ◽  
Titanium Dioxide Nanotubes ◽  
Prosthetic Devices ◽  
Cell Parameters

Titanium is one of the biomaterials commonly used for prosthetic devices due to its bio-inert properties. The discovery of titanium dioxide nanotubes (TDNTs) has created a great interest in medical applications such as dental and orthopedic implants. The synthesizing of TDNTs can produce different morphology, sizes and mechanical properties of the nanotubes – depending on the applied method. In this study, an electrochemical anodization method was used for synthesizing the TDNTs. A 100 ml mixture of 99% of ethylene glycol (EG), 1% of deionized water and 1 wt.% of ammonium fluoride (NH4F) was used as the electrolyte of the electrochemical cell. Parameters such as anodization time and the voltage applied were used to alter the morphology of the TDNTs formed. The produced nanotubes were analyzed and characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and microhardness tester. The SEM results showed that the formed diameter of nanotubes was mainly affected by the anodizing voltage. The wall thickness was found to be irrelevant to the parameters conducted in this study. The diameter of nanotubes formed with an anodizing voltage of 30, 45 and 60 V have the diameters ranging from 46 nm to 71 nm. All of the TDNTs samples formed have a wall thickness between 11 nm and 13 nm. With the use of EG and NH4F as an electrolyte, the array of TDNTs with honeycomb structure was formed. In general, hardness test showed that the hardness of the nanotubes was inversely proportional with the anodizing time. The anodizing voltage only has little effect on the hardness of the nanotubes. The nanotubes formed by 60 V have about 3 to 5% lower hardness compared to those formed by 30 V for different anodizing times.

Chemical and orientational imaging of polymeric samples

1994 ◽  
Vol 52 ◽  
pp. 68-69
Author(s):  
H. Ade ◽  
B. Hsiao ◽  
G. Mitchell ◽  
E. Rightor ◽  
A. P. Smith ◽  
...  
Keyword(s):  
Ethylene Terephthalate ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Carbonyl Groups ◽  
Aromatic Rings ◽  
Edge Structure ◽  
X Ray ◽  
Scanning Transmission ◽  
Polymeric Samples ◽  
X Ray Absorption

We have used the Scanning Transmission X-ray Microscope at beamline X1A (X1-STXM) at Brookhaven National Laboratory (BNL) to acquire high resolution, chemical and orientation sensitive images of polymeric samples as well as point spectra from 0.1 μm areas. This sensitivity is achieved by exploiting the X-ray Absorption Near Edge Structure (XANES) of the carbon K edge. One of the most illustrative example of the chemical sensitivity achievable is provided by images of a polycarbonate/pol(ethylene terephthalate) (70/30 PC/PET) blend. Contrast reversal at high overall contrast is observed between images acquired at 285.36 and 285.69 eV (Fig. 1). Contrast in these images is achieved by exploring subtle differences between resonances associated with the π bonds (sp hybridization) of the aromatic groups of each polymer. PET has a split peak associated with these aromatic groups, due to the proximity of its carbonyl groups to its aromatic rings, whereas PC has only a single peak.

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