Sputter-deposition and characterization of paramelaconite

2003 ◽  
Vol 18 (7) ◽  
pp. 1535-1542 ◽  
Author(s):  
K. J. Blobaum ◽  
D. Van Heerden ◽  
A. J. Wagner ◽  
D. H. Fairbrother ◽  
T. P. Weihs
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metastable Phase ◽  
Heat Of Formation ◽  
Sputter Deposition ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Multilayer Foils ◽  
Out Of Plane ◽  
Processing Techniques

While processing techniques for deposition of CuOx/Al multilayer foils were being developed, a method for synthesizing paramelaconite (Cu4O3) was serendipitously discovered. These paramelaconite films were successfully synthesized by sputter-deposition from a CuO target. Milligram quantities of uncontaminated material were produced enabling new studies of the morphology, stoichiometry, and thermodynamics of this unique copper oxide. At moderate temperatures, equiaxed paramelaconite grains deposited with a strong out-of-plane texture; at lower temperatures the paramelaconite grains showed no texture but were columnar in geometry. X-ray photoelectron spectroscopy showed that the as-deposited Cu4O3 had a nonstoichiometric Cu:O ratio of 1.7:1; the ratio of Cu+ to Cu2+ was 1.8:1. On heating, this phase decomposed into CuO and Cu2O at temperatures ranging from 400 to 530 °C. Using differential scanning calorimetry, the heat of formation and Gibbs free energy for Cu4O3 were estimated to be −453 and −279 kJ/mol, respectively. On the basis of these calculations and our observations, we confirmed that Cu4O3 is a metastable phase.

Synthesis and Characterization of a POSS-Urethane Hybrid Coating for Use in the Corrosion Protection of Metal

2005 ◽  
Vol 23 ◽  
pp. 231-234 ◽  
Author(s):  
Matthew Oaten ◽  
Namita Roy Choudhury
Keyword(s):  
Corrosion Protection ◽  
Photoelectron Spectroscopy ◽  
Hybrid Coating ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
Clean Steel ◽  
X Ray ◽  
Oligomeric Silsesquioxane ◽  
Steel Substrates

The potential of cyclic silsesquioxanes as flexible coatings has been explored in this work for corrosion protection of metal. A polyurethane coating containing an inorganic polyhedral oligomeric silsesquioxane (POSS) was synthesized and characterized by means of photo-acoustic infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle and modulated differential scanning calorimetry (MDSC). The coating has been applied to clean steel substrates via dip and spin coating. The POSS based hybrid coating is found to be uniform, dense and essentially defect free. XPS shows that the coating forms a lamellar layered structure on the substrate.

Thermal and structural characterization of the ZrO2−x(OH)2xto ZrO2 transition

2001 ◽  
Vol 16 (8) ◽  
pp. 2209-2212 ◽  
Author(s):  
E Torres-GarciÁa ◽  
A. Peláiz-Barranco ◽  
C. Vázquez-Ramos ◽  
G. A. Fuentes
Keyword(s):  
High Resolution ◽  
Metastable Phase ◽  
Nitrogen Adsorption ◽  
The Other ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
X Ray ◽  
Exothermic Process

The exothermic process that occurs around 700 K during calcination of ZrO2−x(OH)2x, associated with the crystallization of the low-temperature tetragonal metastable phase of ZrO2, was analyzed using x-ray diffraction, high-resolution thermogravimetric analysis (TGA), nitrogen adsorption, and modulated differential scanning calorimetry (MDSC). High-resolution TGA allowed us to determine the water loss, resulting from condensation of OH− groups. The amount was 0.137 wt% in our case, equivalent to 1.7 × 10−2 mol of H2O/mol of ZrO2. That corresponds to about one −OH group per nm2 being lost in that process. By using MDSC we determined that the change in enthalpy (∆Hglobal = −15.49 kJ/mol of ZrO2) was the result of two parallel contributions. One of them was reversible and endothermic (∆Hrev = 0.11 kJ/mol of ZrO2), whereas the other was irreversible and exothermic (∆Hirrev = −15.60 kJ/mol of ZrO2). The variability and magnitude of the exotherm, as well as the fact that the accompanying weight loss is so small, are consistent with a mechanism involving the formation of tetragonal nuclei, rather than global crystallization, and hence depend on the number of nuclei so formed.

Thermal Characterization of the Interaction of Silanes with a Dihydroxy Vulcanized Fluoroelastomer

2006 ◽  
Vol 79 (5) ◽  
pp. 765-782
Author(s):  
Michael Benjamin Sands ◽  
Vijay Subramanian ◽  
Guangzhao Mao
Keyword(s):  
Photoelectron Spectroscopy ◽  
Vinylidene Fluoride ◽  
Thermal Characterization ◽  
Peak Shift ◽  
Amine Group ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Lower Temperature ◽  
Bisphenol Af

Abstract The reactivity of aminosilane and vinylsilane with a dihydroxy (Bisphenol AF) crosslinkable fluoroelastomer containing only vinylidene fluoride (VF2) and hexafluoropropylene (HFP) was monitored using Differential Scanning Calorimetry (DSC) and X-ray Photoelectron Spectroscopy (XPS). The DSC results showed that the introduction of an aminosilane, or a combination of aminosilane and vinylsilane solutions, to the cure system of the fluoroelastomer resulted in a peak shift. This shift indicates that crosslinking in fluoroelastomer-silane system occurs at a lower temperature when aminosilane is present. Results also confirm that the organofunctional group on the silane reacts with the elastomer. XPS analysis of the silane-coated fluoroelastomer heated at 120 °C, 160 °C and 200 °C reveals that dehydrofluorination of the polymer is one of the steps in the reaction. It is our hypothesis that the amine group on the aminosilane is a contributor to the dehydrofluorination of the fluoroelastomer.

Chemical synthesis and characterization of polyaniline-molybdenum trisulfide composite

1999 ◽  
Vol 14 (5) ◽  
pp. 1805-1813 ◽  
Author(s):  
Florence Fusalba ◽  
Daniel Bélanger
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Synthesis And Characterization ◽  
Scanning Electron Micrographs ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Chemical Polymerization ◽  
X Ray ◽  
Scanning Electron

A novel polyaniline-molybdenum trisulfide composite has been prepared by chemical polymerization from an acidic (1 M HCl) aqueous solution containing aniline and ammonium tetrathiomolybdate. The presence of molybdenum trisulfide in the polyaniline matrix induces morphological change to the polymer as evidenced by scanning electron micrographs. X-ray diffraction and differential scanning calorimetry indicate that polyaniline-molybdenum trisulfide is slightly less crystalline than polyaniline-HCl. X-ray photoelectron spectroscopy (XPS) and elemental analysis have been used to confirm the presence of molybdenum trisulfide in the polymer matrix. The XPS data also confirm that molybdenum trisulfide and tetrathiomolybdate anions are present with polyaniline to form a new inorganic-organic composite.

Preparation and Characterization of APTES Modified Bioglass

2008 ◽  
Vol 368-372 ◽  
pp. 1215-1217
Author(s):  
Li Ren ◽  
Tian Yi Yang ◽  
Ying Gang Zhao ◽  
Na Ru Zhao
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Structures ◽  
Polymer Materials ◽  
Attenuated Total Reflectance ◽  
Scanning Calorimetry ◽  
Total Reflectance ◽  
X Ray ◽  
Fourier Transformed Infrared Spectroscopy ◽  
Sbf Solution

Bioglass (BG) particles were treated by 3-aminopropyltriethoxysilane (APTES) in order to improve the interface compatibility with polymer materials. The surface structures of modified BG were characterized through Fourier transformed infrared spectroscopy with attenuated total reflectance accessory, thermogravimetric analysis, differential scanning calorimetry analysis and X-ray photoelectron spectroscopy. The results showed that APTES was successfully grafted on the surface of BG. The biomineralization properties of APTES modified bioglass were also studied through FTIR, XRD and SEM. Results showed that hydroxylcarbonateapatite (HCA) was formed on the surface of modified BG after soaked into SBF solution. It was shown that the APTES modified BG could possess good mineralization properties and could be intended as a composition of scaffolds for bone tissue engineering applications.

Low-Temperature Synthesis and Characterization of Single-Phase BiFeO3 Nano-Crystallites

2012 ◽  
Vol 164 ◽  
pp. 115-119
Author(s):  
Hui Fen Guo ◽  
Shu Xia Guo ◽  
Li Ben Li
Keyword(s):  
Photoelectron Spectroscopy ◽  
Single Phase ◽  
Crystallization Process ◽  
Exothermic Peak ◽  
Scanning Calorimetry ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
X Ray ◽  
Intermediate Phases

Single-phase BiFeO3 (BFO) nano-crystallites were successfully synthesized in the temperature range of 500  750 oC by a simple diluted HNO3 sol method. During the crystallization process no intermediate phases were observed. As an example, we studied the electronic structure and thermodynamic stability of the BFO nano-crystallites calcined at 750 oC by X-ray photoelectron spectroscopy (XPS) and differential scanning calorimetry (DSC). The XPS showed that the oxidation state of Fe is Fe3+. The DSC indicated a novel exothermic peak at about 769 oC during cooling, which might be due to Bi2Fe4O9 or some other phases produced in the decomposition of BFO at high temperature.

Preparation and characterization of conducting nylon 6 fibers

2009 ◽  
Vol 24 (8) ◽  
pp. 2728-2735 ◽  
Author(s):  
A. Saritha Chandran ◽  
Sunil K. Narayanankutty
Keyword(s):  
Photoelectron Spectroscopy ◽  
In Situ Polymerization ◽  
Fiber Surface ◽  
Nylon 6 ◽  
Etching Time ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

Conducting nylon 6 fibers were prepared by in situ polymerization of aniline on to the fiber surface, after providing a chemical etching treatment to the fibers using chromic acid. The properties of the etched and polyaniline (PANI) coated fibers were evaluated using scanning electron microscopy, x-ray photoelectron spectroscopy, infrared spectroscopy, x-ray diffraction, thermogravimetry, and differential scanning calorimetry. Though the etching process caused a marginal decline in the mechanical properties of the fiber, it provided a reasonably rough surface for PANI adhesion and enhanced the conductivity of the fiber. The conductivity increased from 4.22 × 10−2 to 3.72 × 10−1 S/cm at an etching time of 4 h.

Studies on the Preparation, Characterization and Solubility of -Cyclodextrin-Roxythromycin Inclusion Complexes

2009 ◽  
Vol 2 (2) ◽  
pp. 523-530
Author(s):  
D. Nagasamy Venkatesh ◽  
S. Karthick ◽  
M. Umesh ◽  
G. Vivek ◽  
R.M. Valliappan ◽  
...  
Keyword(s):  
Dissolution Rate ◽  
Inclusion Complexes ◽  
Phase Solubility ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ir Studies ◽  
Poorly Soluble ◽  
Poorly Soluble Drug

Roxythromycin/ β-cyclodextrin (Roxy/ β-CD) dispersions were prepared with a view to study the influence of β-CD on the solubility and dissolution rate of this poorly soluble drug. Phase-solubility profile indicated that the solubility of roxythromycin was significantly increased in the presence of β-cyclodextrin and was classified as AL-type, indicating the 1:1 stoichiometric inclusion complexes. Physical characterization of the prepared systems was carried out by differential scanning calorimetry (DSC), X-ray diffraction studies (XRD) and IR studies. Solid state characterization of the drug β-CD binary system using XRD, FTIR and DSC revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement of dissolution rate.

Thermal Behaviour of Candesartan Active substance and in pharmaceutical compounds

2017 ◽  
Vol 68 (8) ◽  
pp. 1895-1902
Author(s):  
Ioana Cristina Tita ◽  
Eleonora Marian ◽  
Bogdan Tita ◽  
Claudia Crina Toma ◽  
Laura Vicas
Keyword(s):  
Thermal Behaviour ◽  
Active Substance ◽  
Pharmaceutical Research ◽  
Pharmaceutical Product ◽  
Nitrogen Atmosphere ◽  
Pure Substance ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ft Ir

Thermal analysis is one of the most frequently used instrumental techniques in the pharmaceutical research, for the thermal characterization of different materials from solids to semi-solids, which are of pharmaceutical relevance. In this paper, simultaneous thermogravimetry/derivative thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC) were used for characterization of the thermal behaviour of candesartan cilexetil � active substance (C-AS) under dynamic nitrogen atmosphere and nonisothermal conditions, in comparison with pharmaceutical product containing the corresponding active substance. It was observed that the commercial samples showed a different thermal profile than the standard sample, caused by the presence of excipients in the pharmaceutical product and to possible interaction of these with the active substance. The Fourier transformed infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRPD) were used as complementary techniques adequately implement and assist in interpretation of the thermal results. The main conclusion of this comparative study was that the TG/DTG and DSC curves, together with the FT-IR spectra, respectively X-ray difractograms constitute believe data for the discrimination between the pure substance and pharmaceutical forms.

The Growth and Characterization of Germanium-Carbon Alloy Thin Films

1992 ◽  
Vol 270 ◽  
Author(s):  
Haojie Yuan ◽  
R. Stanley Williams
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Vacuum Chamber ◽  
Optical Band Gap ◽  
High Vacuum ◽  
Optical Absorption Spectroscopy ◽  
Alloy Thin Film ◽  
New Materials ◽  
X Ray

ABSTRACTThin films of pure germanium-carbon alloys (GexC1−x with x ≈ 0.0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0) have been grown on Si(100) and A12O3 (0001) substrates by pulsed laser ablation in a high vacuum chamber. The films were analyzed by x-ray θ-2θ diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), conductivity measurements and optical absorption spectroscopy. The analyses of these new materials showed that films of all compositions were amorphous, free of contamination and uniform in composition. By changing the film composition, the optical band gap of these semiconducting films was varied from 0.00eV to 0.85eV for x = 0.0 to 1.0 respectively. According to the AES results, the carbon atoms in the Ge-C alloy thin film samples has a bonding configuration that is a mixture of sp2 and sp3 hybridizations.

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