Preparation of γ–Fe2O3 nanoparticles from a nonaqueous precursor

2001 ◽  
Vol 16 (12) ◽  
pp. 3471-3475 ◽  
Author(s):  
P. Deb ◽  
A. Basumallick
Keyword(s):  
Heat Treatment ◽  
Thermal Characteristics ◽  
Homogeneous Solution ◽  
Nanosized Particles ◽  
Narrow Size Distribution ◽  
Fe2o3 Nanoparticles ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering

Nanosized particles of γ–Fe2O3 were prepared by heat treatment of the precipitates, obtained from a homogeneous solution of stearic acid and hydrated iron(III) nitrate. The compositional and thermal characteristics of the precipitates were studied with the aid of infrared spectroscopy and differential scanning calorimetry. The x-ray diffraction and small-angle x-ray scattering investigation shows that γ–Fe2O3 nanoparticles with narrow size distribution can be prepared successfully by this route.

Thermotropic behavior of sodium cholesteryl carbonate

2009 ◽  
Vol 24 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Rabkwan Chuealee ◽  
Timothy S. Wiedmann ◽  
Teerapol Srichana
Keyword(s):  
Phase Behavior ◽  
Chemical Structure ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Wave Number ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
C Nmr

Sodium cholesteryl carbonate ester (SCC) was synthesized, and its phase behavior was studied. The chemical structure was assessed by solid-state infrared spectroscopy based on vibration analysis. The wave number at 1705 and 1276 cm−1 corresponds to a carbonyl carbonate and O–C–O stretching of SCC, respectively. Molecular structure of SCC was further investigated with 1H and 13C NMR spectroscopy. The chemical shift, for the carbonyl carbonate resonance appeared at 155.5 ppm. A molecular mass of SCC was at m/z of 452. Differential scanning calorimetry (DSC), video-enhanced microscopy (VEM) together with polarized light microscopy, and small-angle x-ray scattering (SAXS) were used to characterize the phase behavior as a function of temperature of SCC. Liquid crystalline phase was formed with SCC. Based on the thermal properties and x-ray diffraction, it appears that SCC forms a structure analogous to the type II monolayer structure observed with cholesterol esters.

In Situ High Temperature X-Ray Diffraction Studies of Modified Poly(Ethylene Terephthalate)

1992 ◽  
Vol 36 ◽  
pp. 379-386
Author(s):  
T. Blanton ◽  
R. Seyler
Keyword(s):  
High Temperature ◽  
Ethylene Terephthalate ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
Poly Ethylene Terephthalate ◽  
Poly Ethylene ◽  
Pet Crystallization

The effect of dimethyl-5-sodiosulfoisophthalate, SIP, on poly(ethylene terephthalate), PET, crystallization has been studied using in situ high-temperature x-ray diffraction, HTXRD. At low levels of SIP modification, PET-like crystallinity was observed. At high SIP levels, clustering of polyester ionomers was observed and crystallization was significantly suppressed. The HTXRD data along with differential scanning calorimetry, DSC, and small angle x-ray scattering, SAXS, indicate that the change from bulk crystallization to bulk ionomer formation occurred when 8-12 mol% of the diester linkages contained SIP.

scholarly journals Microstructure Evolution and Performance Improvement of Hypereutectic Al–Mg2Si Metallic Composite with Ca or Sb

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2714
Author(s):  
Min Zuo ◽  
Boda Ren ◽  
Zihan Xia ◽  
Wenwen Ma ◽  
Yidan Lv ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Nucleation Behavior ◽  
X Ray ◽  
Primary Mg2si ◽  
Before And After ◽  
And Performance ◽  
Hardness Values

In this article, the modification effects on Al–Mg2Si before and after heat treatment were investigated with Ca, Sb, and (Ca + Sb). In comparison with single Ca or Sb, the samples with composition modifiers (Ca + Sb) had the optimal microstructure. The sample with a molar ratio for Ca-to-Sb of 1:1 obtained relatively higher properties, for which the Brinell hardness values before and after heat treatment were remarkably increased by 31.74% and 28.93% in comparison with bare alloy. According to differential scanning calorimetry analysis (DSC), it was found that the nucleation behavior of the primary Mg2Si phase could be significantly improved by using chemical modifiers. Some white particles were found to be embedded in the center of Mg2Si phases, which were deduced to be Ca5Sb3 through X-ray diffraction (XRD) and field-emission scanning electron microscope (FESEM) analyses. Furthermore, Ca5Sb3 articles possess a rather low mismatch degree with Mg2Si particles based on Phase Transformation Crystallography Lab software (PTCLab) calculation, meaning that the efficient nucleation capability of Ca5Sb3 for Mg2Si particles could be estimated.

Study of the structure and thermal characteristics of nanocomposites based on polyvinyl alcohol and intercalated montmorillonite

2019 ◽  
pp. 089270571987919
Author(s):  
Volodymyr Krasinskyi ◽  
Ivan Gajdos ◽  
Oleh Suberlyak ◽  
Viktoria Antoniuk ◽  
Tomasz Jachowicz
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Acrylic Acid ◽  
Polyvinyl Alcohol ◽  
Thermal Characteristics ◽  
Degree Of Crystallinity ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
The Degree Of Crystallinity

The structure and thermal characteristics of nanocomposites based on polyvinyl alcohol (PVA) and montmorillonite (MMT) intercalated with polyvinylpyrrolidone were investigated by X-ray diffraction analysis and differential scanning calorimetry. The modification of PVA with intercalated MMT reduces the degree of crystallinity of the resulting nanocomposites but significantly increases their thermal stability. Under ultrasound, the intercalated MMT was completely distributed in a PVA solution and formed a monocrystalline structure. Films based on PVA with modified MMT were cross-linked at 110°C in the presence of 5 wt% acrylic acid and 0.5 wt% Ferrous(II) sulfate as an initiator. The formed films have a homogeneous cross-linked structure.

Synthesis of nanocomposite coating of electrodeposed amorphic layers of the Ni–P–W system

2020 ◽  
pp. 53-60
Author(s):  
A. V. Krasikov
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Phase Composition ◽  
Diffraction Analysis ◽  
Nanocomposite Coating ◽  
Nanocrystalline Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray

The processes of the formation of the nanocomposite coating of Ni–11.5% P–5%W were studied during the heat treatment of amorphous electrodeposited layers. Using the method of differential scanning calorimetry, the temperature of the onset of crystallization of the nanocrystalline phase Ni3P was determined. X-ray diffraction analysis showed that heat treatment produces Ni3P phosphides and, presumably, Ni5P2, the size of which, according to electron microscopy, is 5–50 nm. The influence of the duration of heat treatment on the phase composition and microhardness of coatings is investigated.

Atomic layer deposition of HfO2, Al2O3, and HfAlOx using O3 and metal(diethylamino) precursors

2007 ◽  
Vol 22 (12) ◽  
pp. 3455-3464 ◽  
Author(s):  
Rajesh Katamreddy ◽  
Ronald Inman ◽  
Gregory Jursich ◽  
Axel Soulet ◽  
Christos Takoudis
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Thermal Characteristics ◽  
Atomic Layer ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Metal Precursors ◽  
Layer Deposition ◽  
Xrd Techniques

Tetrakis-diethylamino hafnium (TDEAH), tris-diethylamino aluminum (TDEAA), and ozone were used for the atomic layer deposition (ALD) of HfO2, Al2O3, and HfAlOx films. The ALD rates were measured to be 1.1 Å/cycle for HfO2 and 1.3 Å/cycle for Al2O3. The ALD temperature windows were found to be between 200 and 325 °C for TDEAA, and between 200 and 275 °C for TDEAH. The overlap of these ALD windows between 200 and 275 °C is critical for ALD of the composite film, HfAlOx. In addition to the overlapping ALD temperature windows, the two metal precursors have similar thermal characteristics, as shown by TGA and differential scanning calorimetry. As-deposited films and films postannealed at 600 and 800 °C films were analyzed using Fourier transformed infrared (FTIR) spectroscopy, x-ray photoelectron spectroscopy, and x-ray diffraction (XRD) techniques. FTIR spectra revealed interfacial oxide growth during deposition of both HfO2 and Al2O3 whose thickness increased with annealing temperature. The FTIR data also indicated hydroxyl and nitrate groups in the films; these species were removed after annealing in Ar at a temperature of ⩾600 °C. Both FTIR and XRD results indicated the crystallization of pure HfO2 after annealing at temperatures as low as 600 °C. On the other hand, pure Al2O3 remained amorphous after annealing at temperatures up to 800 °C. XRD data of the composite HfAlOx film show that films deposited by alternating five cycles of HfO2 and one cycle of Al2O3 remained amorphous after annealing at 600 °C. Rutherford backscattering analysis of HfAlOx deposited with a varied number of alternating HfO2 and Al2O3 cycles demonstrated a strong correlation between the cyclic dosage of TDEAA and TDEAH and the film composition.

scholarly journals Pengaruh Metode Sintesis Silika Mesopori SBA-15 terhadap Analisis Differential Scanning Calorimetry dan Pengukuran Low Angles X-Ray Diffraction

2018 ◽  
Vol 5 (1) ◽  
pp. 39
Author(s):  
Ridhawati Ridhawati ◽  
Abdul Wahid Wahab ◽  
Nursiah La Nafie ◽  
Indah Raya
Keyword(s):  
Crystal Structure ◽  
Differential Scanning Calorimetry ◽  
Mesoporous Silica ◽  
Crystal Size ◽  
Sol Gel ◽  
Thermal Characteristics ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hydrothermal Methods

Mesoporous silica SBA-15 is an interesting material having highly ordered nanopores and large surface area, which is synthesized by sol gel and hydrothermal methods. In this study, mesoporous silica SBA-15 was synthesised with two different methods and the characteris was using X-Ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). SBA-15 was prepared TEOS as precursor and Pluronic 123 as surfactant. Thermoporous mesoporous DSC thermogram results of the SBA-15A mesoporous silica is (Tg 79oC and Tc 158oC). This is relatively lower than SBA-15B (Tg 86oC and Tc 158oC). The measurement of low angle X-Ray Diffraction SBA-15A has a crystal size 9.46 nm and SBA-15B has a crystal size 9.96 nm. The synthesis of SBA-15 using the hydrothermal method needs to be studied further to obtain thermal characteristics and a more stable crystal structure

scholarly journals Photocatalytic Degradation of 2,4-Dichlorophenol Using Nanosized Na2Ti6O13/TiO2Heterostructure Particles

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Zicong Jian ◽  
Shaobin Huang ◽  
Yongqing Zhang
Keyword(s):  
Degradation Rate ◽  
Photocatalytic Property ◽  
Tetrabutyl Titanate ◽  
Composite Particles ◽  
Nanosized Particles ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Initial Concentration ◽  
X Ray ◽  
Scanning Electron

Na2Ti6O13/TiO2composite particles were synthesized through the hydrolyzation of tetrabutyl titanate in a reverse microemulsion and characterized by thermogravimetry and differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), and scanning electron microscope (SEM). The photocatalytic property of Na2Ti6O13/TiO2was evaluated by degradation of 2,4-dichlorophenol(2,4-DCP) under 40 W ultraviolet lamp (λ=365 nm) irradiation and compared with commercial P25-TiO2in the same condition. The results showed that the synthesized nanobelts Na2Ti6O13/TiO2heterostructures had typical width from 80 to 100 nm, with thickness less than 40 nm and length up to 5 μm. Such Na2Ti6O13/TiO2nanosized particles exhibited better photocatalytic activity than that of P25-TiO2, and the degradation rate of 2,4-DCP with initial concentration of 0.02 g/L reached 99.4% at the end of 50 min.

Heterocyclic and aromatic based polyurethane scaffolds: morphology and crystallinity studied by X-ray diffraction, small-angle X-ray scattering and differential scanning calorimetry

2013 ◽  
Vol 46 (4) ◽  
pp. 980-992 ◽  
Author(s):  
Tarek M. Madkour ◽  
Sahar K. Mohamed
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Small Angle ◽  
Aromatic Diamine ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
Chain Extenders ◽  
Ray Scattering

The morphology, crystallinity and X-ray diffraction of speciality heterocyclic and aromatic based polyurethane and poly(urethane–urea) elastomers synthesized via a one-shot polymerization method were studied. The samples were chain extended by mixtures of aliphatic diols and furanic or aromatic diamine chain extenders. Small-angle X-ray scattering (SAXS) measurements confirmed the results obtained by differential scanning calorimetry (DSC) and revealed the presence of phases with sharp phase boundaries. The SAXS patterns are best fitted with a model that consists of liquid-like ordered polydisperse spheres. Most of the samples were shown to be poorly crystalline, but some soft-phase crystals do exist and these melted at about 353 K as confirmed by DSC and temperature-dependent wide-angle X-ray diffraction. Annealing at 273 K did not affect the thermal stability but influenced the morphology of the samples. The effect of annealing on the samples of poly(urethane–urea) extended using diamine chain extenders was smaller than that for polyurethane samples, which indicates a much higher thermal stability of the poly(urethane–urea) samples owing to the formation of bidentate hydrogen-bond networks across the urea groups.

A time-resolved SAXS study on the crystalline morphology of long-term stored isotactic polypropylene

2004 ◽  
Vol 37 (2) ◽  
pp. 295-299 ◽  
Author(s):  
Jun-Ting Xu ◽  
Yu-Jin Zhang ◽  
Zhi-Qiang Fan
Keyword(s):  
Isotactic Polypropylene ◽  
Crystal Form ◽  
Crystalline Morphology ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Time Resolved ◽  
Crystal Forms ◽  
X Ray ◽  
X Ray Scattering

The crystalline morphology of a long-term stored metallocene isotactic polypropylene (mPP) has been studied with time-resolved small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD), and compared with that of the freshly crystallized sample. It was found that both α and γ crystal forms occur in the long-term stored mPP, whereas freshly crystallized mPP contains only the α crystal form. Double SAXS peaks were observed for the long-term stored mPP, which can be assigned to the α and γ crystals. Based on the SAXS result, it is inferred that the crystal stacks of the α and γ forms in the long-term stored mPP are arranged according to the block mode.

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