Study of NiFe/SiO2 Nanocomposites

2001 ◽  
Vol 703 ◽  
Author(s):  
S. Hui ◽  
Y.D. Zhang ◽  
T. D. Xiao ◽  
Mingzhong Wu ◽  
Shihui Ge ◽  
...  
Keyword(s):  
Chemical Reaction ◽  
Composite System ◽  
Volume Fraction ◽  
Treatment Temperature ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Sio2 Nanocomposites ◽  
Wet Chemical ◽  
Fe Alloys

ABSTRACT(Ni75Fe25)v/(SiO2)1-v nanocomposites with v =0.5, 0.7, and 1.0, where 75 denotes the atomic percent of Ni in the Ni-Fe alloy phase and v denotes the volume fraction of the magnetic constituent in the composite, were synthesized using a wet chemical approach. The x-ray diffraction and TEM experiments show that the synthetic NiFe/SiO2 is a two-phase composite system in that an amorphous insulating SiO2 layer coats each Ni-Fe particle. The Ni-Fe particle is in a fcc Ni-Fe alloy state. Its size can be controlled over a rather large range between 5 nm to 70 nm by adjusting the reaction parameters. Particular attention was paid to reduce the chemical reaction temperature so as to insure the smallness of the particle size. Meanwhile, measurements of the saturation magnetization indicated that the higher the heat treatment temperature, the more complete the chemical reaction to form the Ni-Fe alloys from precursor materials.

scholarly journals Structure Formation and Corrosion Behaviour of Quasicrystalline Al–Ni–Fe Alloys

2017 ◽  
Vol 18 (2) ◽  
pp. 222-227 ◽  
Author(s):  
О.V. Sukhova ◽  
V.A. Polonskyy ◽  
К.V. Ustinovа
Keyword(s):  
Room Temperature ◽  
Volume Fraction ◽  
Corrosion Behaviour ◽  
Corrosion Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acidic Solutions ◽  
Decagonal Phase ◽  
Fe Alloys ◽  
Saline Solutions

The formation of quasicrystalline decagonal phase and related crystalline phases was investigated by a combination of optical metallography, powder X-ray diffraction, atomic absorption spectroscopy and differential thermal analysis. Corrosion behaviour of quasicrystal Al–Ni–Fe alloys was studied by gravimetric and potentiodynamic polarization experiments in saline and acidic solutions at room temperature. The decagonal phase exhibits two modifications (AlFe- and AlNi-based) depending on the composition. In Al72Ni13Fe15 alloy it coexists with monoclinic Al5FeNi phase. In Al71.6Ni23Fe5.4 alloy crystalline Al13(Ni,Fe)4, Al3(Ni,Fe)2, and Al3(Ni,Fe) phases are seen adjacent to the quasicrystalline decagonal phase. Stability of quasicrystal phase up to room temperature was shown to be connected with its incomplete decomposition during cooling at a rate of 50 K/min. Al72Ni13Fe15 alloy has more than twice larger volume fraction of this phase compared to that of Al71.6Ni23Fe5.4 alloy. A dependence of microhardness on composition was observed as well, with Al72Ni13Fe15 alloy having substantially higher values. In acidic solutions, Al71.6Ni23Fe5.4 alloy showed the best corrosion performance. In saline solutions, the investigated alloys remained mainly untouched by corrosion. Mass-change kinetics exhibited parabolic growth rate. 

scholarly journals Effect of the γ→ε Phase Transition on Transformation-Induced Plasticity (TRIP) of Nickel-Free High Nitrogen Steel at Low Temperatures

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 710
Author(s):  
Natalia Narkevich ◽  
Yevgeny Deryugin ◽  
Yury Mironov
Keyword(s):  
Volume Fraction ◽  
Tensile Load ◽  
X Ray Diffraction ◽  
High Nitrogen Steel ◽  
Transformation Induced Plasticity ◽  
X Ray ◽  
Root Cause ◽  
Nitrogen Steel ◽  
Ε Phase ◽  
Ε Martensite

The deformation behavior, mechanical properties, and microstructure of Fe-Cr-Mn-0.53%N austenitic stainless steel were studied at a temperature range of 77 up to 293 K. The dynamics of the steel elongation were non-monotonic with a maximum at 240–273 K, when peaks of both static atom displacements from their equilibrium positions in austenite and residual stresses in the tensile load direction were observed. The results of X-ray diffraction analysis confirmed that the only stress-induced γ→ε-martensite transformation occurred upon deformation (no traces of the γ→α′ one was found). In this case, the volume fraction of ε-martensite was about 2–3%. These transformation-induced plasticity (TRIP) patterns were discussed in terms of changes in the phase composition of steel as the root cause.

Nanostructured TiO2-Based Composites for Light Absorption

2014 ◽  
Vol 975 ◽  
pp. 207-212
Author(s):  
Dayse I. dos Santos ◽  
Olayr Modesto Jr. ◽  
Luis Vicente A. Scalvi ◽  
Americo S. Tabata
Keyword(s):  
Metal Oxide ◽  
Light Absorption ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Oxide Powders

Metal oxide nanocomposites were prepared by two different routes: polyol and sol-gel. Characterization by X ray diffraction showed that the first process produces directly a two-phase material, while the sol-gel powder never showed second phase below 600°C. Light spectroscopy of the treated powders indicated similarities for the processed materials. Although the overall material compositions are about the same, different structural characteristics are found for each processing. With the exception of Ti-Zn materials, all the double metal oxide powders showed higher absorbance than either TiO2 powder.

Effect of the BSCCO superconducting properties by tiny Y2O3 addition

2016 ◽  
Vol 30 (26) ◽  
pp. 1650328
Author(s):  
Yan Dong ◽  
Aimin Sun ◽  
Bin Xu ◽  
Hongtao Zhang ◽  
Meng Zhang
Keyword(s):  
Volume Fraction ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Critical Transition Temperature ◽  
Solid State Reaction Technique ◽  
X Ray ◽  
Oxide Addition ◽  
One Step ◽  
Step Transition ◽  
Y2o3 Addition

In this paper, the effect of tiny Y2O3 addition in (Bi,[Formula: see text]Pb)-2223 superconductor prepared by solid state reaction technique was studied. The properties of samples have been investigated via X-ray diffraction (XRD), resistance–temperature ([Formula: see text]–[Formula: see text]) curve, scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). XRD data indicated that all samples are multiphase and the major phases are high-temperature phases and low-temperature phases. The volume fraction of (Bi,[Formula: see text]Pb)-2223 is not great change with tiny Y2O3 addition. All samples exhibit superconducting phase with the critical transition temperature and one-step transition, however, the transition width was decreased with the Y2O3 addition up to 0.04 wt.% and sharp increased with the excessive oxide addition. SEM pictures show that the Y2O3 appeared on the flake-type grains surface obviously, but the number and size of the hole between grains are decreased in the 0.04 wt.% addition.

PHASE TRANSITION IN LAYERED PEROVSKITE LIKE MANGANATE Ca3Mn2O7 UNDER HIGH PRESSURE

2001 ◽  
Vol 15 (18) ◽  
pp. 2491-2497 ◽  
Author(s):  
J. L. ZHU ◽  
L. C. CHEN ◽  
R. C. YU ◽  
F. Y. LI ◽  
J. LIU ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Diamond Anvil Cell ◽  
The Other ◽  
Layered Perovskite ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Diamond Anvil

In situ high pressure energy dispersive X-ray diffraction measurements on layered perovskite-like manganate Ca 3 Mn 2 O 7 under pressures up to 35 GPa have been performed by using diamond anvil cell with synchrotron radiation. The results show that the structure of layered perovskite-like manganate Ca 3 Mn 2 O 7 is unstable under pressure due to the easy compression of NaCl-type blocks. The structure of Ca 3 Mn 2 O 7 underwent two phase transitions under pressures in the range of 0~35 GPa. One was at about 1.3 GPa with the crystal structure changing from tetragonal to orthorhombic. The other was at about 9.5 GPa with the crystal structure changing from orthorhombic back to another tetragonal.

scholarly journals Characterization of ferrite nanoparticles for preparation of biocomposites

2017 ◽  
Vol 8 ◽  
pp. 1257-1265 ◽  
Author(s):  
Urszula Klekotka ◽  
Magdalena Rogowska ◽  
Dariusz Satuła ◽  
Beata Kalska-Szostko
Keyword(s):  
Chemical Method ◽  
Ferrite Nanoparticles ◽  
Chemical Activity ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
X Ray ◽  
Transmission Electron ◽  
Wet Chemical

Ferrite nanoparticles with nominal composition Me0.5Fe2.5O4 (Me = Co, Fe, Ni or Mn) have been successfully prepared by the wet chemical method. The obtained particles have a mean diameter of 11–16 ± 2 nm and were modified to improve their magnetic properties and chemical activity. The surface of the pristine nanoparticles was functionalized afterwards with –COOH and –NH2 groups to obtain a bioactive layer. To achieve our goal, two different modification approaches were realized. In the first one, glutaraldehyde was attached to the nanoparticles as a linker. In the second one, direct bonding of such nanoparticles with a bioparticle was studied. In subsequent steps, the nanoparticles were immobilized with enzymes such as albumin, glucose oxidase, lipase and trypsin as a test bioparticles. The characterization of the nanoparticles was acheived by transmission electron microscopy, X-ray diffraction, energy dispersive X-ray and Mössbauer spectroscopy. The effect of the obtained biocomposites was monitored by Fourier transform infrared spectroscopy. The obtained results show that in some cases the use of glutaraldehyde was crucial (albumin).

In Situ X-Ray Diffraction Studies of Crystallization Growth Behavior in ZnO-Bi2O3-B2O3 Glass as a Route to Functional Optical Devices

MRS Advances ◽  
2018 ◽  
Vol 3 (11) ◽  
pp. 563-567 ◽  
Author(s):  
Quentin Altemose ◽  
Katrina Raichle ◽  
Brittani Schnable ◽  
Casey Schwarz ◽  
Myungkoo Kang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Glass Ceramics ◽  
Treatment Temperature ◽  
Crystal Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
In Situ Xrd ◽  
Dsc Measurements ◽  
Transmission Window

ABSTRACTTransparent optical ZnO–Bi2O3–B2O3 (ZBB) glass-ceramics were created by the melt quenching technique. In this work, a melt of the glass containing stoichiometric ratios of Zn/Bi/B and As was studied. Differential scanning calorimeter (DSC) measurements was used to measure the thermal behavior. VIS/NIR transmission measurements were used to determine the transmission window. X-ray diffraction (XRD) was used to determine crystal phase. In this study, we explore new techniques and report a detailed study of in-situ XRD of the ZBB composition in order to correlate nucleation temperature, heat treatment temperature, and heat treatment duration with induced crystal phase.

Mitrofanovite, Pt3Te4, a new mineral from the East Chuarvy deposit, Fedorovo–Pana intrusion, Kola Peninsula, Russia

2018 ◽  
Vol 83 (4) ◽  
pp. 523-530 ◽  
Author(s):  
Victor V. Subbotin ◽  
Anna Vymazalová ◽  
František Laufek ◽  
Yevgeny E. Savchenko ◽  
Chris J. Stanley ◽  
...  
Keyword(s):  
Kola Peninsula ◽  
Electron Backscatter Diffraction ◽  
New Mineral ◽  
Synthetic Analogue ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Identity ◽  
Polarised Light ◽  
Fe Alloys ◽  
Backscatter Diffraction

AbstractMitrofanovite, Pt3Te4, is a new telluride discovered in low-sulfide disseminated ore in the East Chuarvy deposit, Fedorovo–Pana intrusion, Kola Peninsula, Russia. It forms anhedral grains (up to ~20 μm × 50 μm) commonly in intergrowths with moncheite in aggregates with lukkulaisvaaraite, kotulskite, vysotskite, braggite, keithconnite, rustenburgite and Pt–Fe alloys hosted by a chalcopyrite–pentlandite–pyrrhotite matrix. Associated silicates are: orthopyroxene, augite, olivine, amphiboles and plagioclase. Mitrofanovite is brittle; it has a metallic lustre and a grey streak. Mitrofanovite has a good cleavage, along {001}. In plane-polarised light, mitrofanovite is bright white with medium to strong bireflectance, slight pleochroism, and strong anisotropy on non-basal sections with greyish brown rotation tints; it exhibits no internal reflections. Reflectance values for the synthetic analogue of mitrofanovite in air (Ro, Re’ in %) are: 58.4, 54.6 at 470 nm; 62.7, 58.0 at 546 nm; 63.4, 59.1 at 589 nm; and 63.6, 59.5 at 650 nm. Fifteen electron-microprobe analyses of mitrofanovite gave an average composition: Pt 52.08, Pd 0.19, Te 47.08 and Bi 0.91, total 100.27 wt.%, corresponding to the formula (Pt2.91Pd0.02)Σ2.93(Te4.02Bi0.05)Σ4.07 based on 7 atoms; the average of eleven analyses on synthetic analogue is: Pt 52.57 and Te 47.45, total 100.02 wt.%, corresponding to Pt2.94Te4.06. The density, calculated on the basis of the formula, is 11.18 g/cm3. The mineral is trigonal, space group R$\overline 3 $m, with a = 3.9874(1), c = 35.361(1) Å, V = 486.91(2) Å3 and Z = 3. The crystal structure was solved and refined from the powder X-ray-diffraction data of synthetic Pt3Te4. Mitrofanovite is structurally and chemically related to moncheite (PtTe2). The strongest lines in the powder X-ray diffraction pattern of synthetic mitrofanovite [d in Å (I) (hkl)] are: 11.790(23)(003), 5.891(100)(006), 2.851(26)(107), 2.137(16)(1013), 2.039(18)(0114), 1.574(24)(0120), 1.3098(21)(0027). The structural identity of natural mitrofanovite with synthetic Pt3Te4 was confirmed by electron backscatter diffraction measurements on the natural sample. The mineral name is chosen to honour Felix P. Mitrofanov, a Russian geologist who was among the first to discover platinum-group element mineralisation in the Fedorova–Pana complex.

Study on Synthesis of Calcium Phosphate Biomaterials Containing SMB

2007 ◽  
Vol 330-332 ◽  
pp. 1033-1036 ◽  
Author(s):  
M.H. Li ◽  
Shu Xin Qu ◽  
R. Shen ◽  
N. Yao ◽  
P.D. Ren ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Salvia Miltiorrhiza ◽  
Reaction System ◽  
Absorption Peak ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
Obvious Effect ◽  
X Ray ◽  
Wet Chemical ◽  
Wet Synthesis

Calcium phosphate (CaP) biomaterials containing Chinese medicine, Danshen (Salvia Miltiorrhiza Bunge, SMB), have been synthesized in our previous study via the wet chemical method. However, CaP biomaterials were generally synthesized in the alkaline solution. The purpose of the present study was to investigate the effect of pH on SMB and the influence of SMB on the synthesis of CaP biomaterials. The SMB solutions of different pH from 5.0 to 10.0, were scanned with the UV-VIS spectrophotometer (UV-VIS) in the wavelength ranged from 200.00 to 400.00 nm. CaP biomaterials containing SMB were synthesized from (NH4)2HPO4, Ca(NO3)2, NH4OH and SMB. The filtrates of the wet synthesis of CaP biomaterials containing SMB were measured by UV-VIS. The synthesized CaP biomaterials containing SMB were characterized by the X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). The results showed that the maximum absorption peak appeared at 281.00 nm for solutions of pH 5.0, 6.0 and 7.0. Although there were a new absorption peaks as the pH were 8.0 and 9.0, the absorption curves of SMB became similar to that of SMB as pH at 7.0 after the pH were readjusted to 7.0. The absorption peak appeared an Einstein shift to 347.00 nm at pH 10.0, which did not return to 281.00 nm when the pH of SMB solution was readjusted to 7.0. The absorption peak of filtrates containing SMB of CaP biomaterials reaction system was still at 281.00 nm when their pH was 7.0 and 8.0. Moreover, SMB had no obvious effect on the phase component and functional groups of products. Hence, it could be predicted that calcium phosphate biomaterials containing SMB, such as DCPD and TCP containing SMB, which could be prepared at the pH ranged from 5.0 to 9.0.

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