scholarly journals The effect of structural changes during sintering on the electric and magnetic traits of the Ni96.7Mo3.3 alloy nanostructured powder

2009 ◽  
Vol 41 (2) ◽  
pp. 175-184 ◽  
Author(s):  
L. Ribic-Zelenovic ◽  
M. Spasojevic ◽  
A. Maricic ◽  
M.M. Ristic
Keyword(s):  
Electrical Resistivity ◽  
Magnetic Permeability ◽  
Structural Relaxation ◽  
Crystalline Phase ◽  
Structural Changes ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Fcc Lattice ◽  
Lower Permeability ◽  
Structural Powder

Ni96.7Mo3.3 powder was electrochemically obtained. An X-ray diffraction analysis determined that the powder consisted of a 20% amorphous and 80% crystalline phase. The crystalline phase consisted of a nanocrystalline solid nickel and molybdenum solution with a face-centred cubic (FCC) lattice with a high density of chaotically distributed dislocations and high microstrain value. The scanning electronic microscopy (SEM) showed that two particle structures were formed: larger cauliflower-like particles and smaller dendriteshaped ones. The thermal stability of the alloy was examined by differential scanning calorimetry (DSC) and by measuring the temperature dependence of the electrical resistivity and magnetic permeability. Structural powder relaxation was carried out in the temperature range of 450 K to 560 K causing considerable changes in the electrical resistivity and magnetic permeability. Upon structural relaxation, the magnetic permeability of the cooled alloy was about 80% higher than the magnetic permeability of the fresh powder. The crystallisation of the amorphous portion of the powder and crystalline grain increase occurred in the 630 K to 900 K temperature interval. Upon crystallisation of the amorphous phase and crystalline grain increase, the powder had about 50% lower magnetic permeability than the fresh powder and 3.6 times lower permeability than the powder where only structural relaxation took place.

scholarly journals Effect of milling and annealing on microstructural, electrical and magnetic properties of electrodeposited Ni-11.3 Fe-1.4w alloy

2012 ◽  
Vol 44 (2) ◽  
pp. 197-210 ◽  
Author(s):  
M. Spasojevic ◽  
L. Ribic-Zelenovic ◽  
N. Cirovic ◽  
P. Spasojevic ◽  
A. Maricic
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Magnetic Permeability ◽  
Structural Relaxation ◽  
Structural Changes ◽  
Xrd Analysis ◽  
Ammonium Citrate ◽  
Maximum Increase ◽  
Electrical And Magnetic Properties

A nanostructured Ni-11.3Fe-1.4W alloy deposit was obtained from an ammonium citrate bath at a current density of 600 mAcm-2. XRD analysis shows that the deposit contains an amorphous matrix having embedded nanocrystals of the FCC phase of the solid solution of Fe and W in Ni with the average crystal grain size of 8.8 nm. The deposit has a high internal microstrain value and a high minimum density of chaotically distributed dislocations. The effect of milling and annealing of the Ni-11.3Fe-1.4W alloy on electrical and magnetic properties was studied. Structural changes in the alloy take place during both annealing and milling. Upon deposition, the alloy was heated to 420?C. Heating resulted in structural relaxation which induced a decrease in electrical resistivity and an increase in magnetic permeability of the alloy. Further heating of the alloy at temperatures higher than 4200C led to crystallization which caused a reduction in both electrical resistivity and magnetic permeability. The milling of the alloy for up to 12 hours caused a certain degree of structural relaxation and crystallization of the alloy. The increase in crystal grain size up to 11 nm and the partial structural relaxation induced a decrease in electrical resistivity and an increase in magnetic permeability of the alloy. Heating the powders obtained by milling at 4200C led to complete structural relaxation, reduced electrical resistivity, and increased magnetic permeability. During heating of the powders obtained by milling at temperatures above 420?C, crystallization and a significant increase in crystal grain size occurred, leading to a reduction in both electrical resistivity and magnetic permeability. The best magnetic properties were exhibited by the alloys milled for 12 hours and annealed thereafter at 420?C. In these alloys, crystal grains were found to have an optimum size, and complete relaxation took place, resulting in a maximum increase in magnetic permeability.

scholarly journals Ellagic Acid May Improve Mechanical and Barrier Properties in Films of Starch-A Review Paper

2016 ◽  
Vol 5 (3) ◽  
pp. 61
Author(s):  
J. M. Tirado-Gallegos ◽  
D. R. Sepúlveda-Ahumada ◽  
P. B. Zamudio-Flores ◽  
M. L. Rodríguez-Marin ◽  
Francisco Hernández-Centeno ◽  
...  
Keyword(s):  
Ellagic Acid ◽  
Structural Changes ◽  
Antioxidant Properties ◽  
Barrier Properties ◽  
Packaging Materials ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Film Forming ◽  
Starch Films

<p>Packaging increases the shelf life of food and facilitates its handling, transportation and marketing. The main packaging materials are plastics derived from petroleum, but their accumulation has given rise to environmental problems. An alternative is the use of biodegradable materials. In this regard, starch is an excellent choice because it is an abundant and renewable source with film-forming properties. However, the films obtained from starch have some limitations with respect to their mechanical and barrier properties. Several strategies have been developed in order to improve these limitations, ranging from the addition of lipids to the modification of the polymer structure. The aim of this review was propose the use of ellagic acid as a cross-linking agent that may improves the mechanical and barrier properties in films based on exists reports that phenolic compounds interact with starch-based materials decreasing their rate of retrogradation. Furthermore, ellagic acid is a powerful natural antioxidant, which would allow the production of active packaging with antioxidant properties, in addition to the improvement of the mechanical and barrier properties of starch films. In this concern more studies such as Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis are necessary to verify the structural changes and interactions between starch and ellagic acid. We expect extensive use of it in the future of packaging materials.</p>

Thermal Cycling Treatment and Structural Changes in Cu-Al-Ni Monocrystalline Alloys

2006 ◽  
Vol 514-516 ◽  
pp. 692-696 ◽  
Author(s):  
Rui Jorge C. Silva ◽  
L.A. Matlakhova ◽  
E.C. Pereira ◽  
A.N. Matlakhov ◽  
Sérgio Neves Monteiro ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Structural Changes ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Critical Range ◽  
Cycling Treatment ◽  
Ni Alloy ◽  
Before And After ◽  
Number Of Cycles

In the present work a monocrystalline Cu-13.5Al-4Ni (wt.%) alloy with shape memory effect (SME) submitted to thermal cycling inside the critical range was investigated in terms of number of cycles and resulting structural changes. Attention was paid to the structural changes associated with reversible β1↔γ’1 martensite transformation. The monocrystalline Cu-Al-Ni alloy was produced in Russia, according to a specific technology. The structural characteristic of the alloys was studied through optical microscopy and X-ray diffraction methods using Cu-Kα radiation. Differential scanning calorimetry permitted the determination of the temperature range as well as a thermal effect due to the β1↔γ’1 martensitic reversible transformations, before and after 100, 200 and 300 thermal cycles.

Multiple dielectric anomalies in xBiLaO3–(1 − x)PbTiO3 piezoelectrics

2008 ◽  
Vol 23 (2) ◽  
pp. 565-569 ◽  
Author(s):  
Runrun Duan ◽  
Michael S. Haluska ◽  
Robert F. Speyer
Keyword(s):  
Differential Scanning Calorimetry ◽  
Dielectric Constant ◽  
Excellent Agreement ◽  
Structural Changes ◽  
Dielectric Anomaly ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermally Induced ◽  
X Ray ◽  
Higher Temperature

Compositions of xBiLaO3–(1 − x) PbTiO3 over the range 0 ≤ x ≤ 0.225 were calcined and sintered. The dielectric constant with temperature and differential scanning calorimetry measurements were in excellent agreement with respect to Curie-like tetragonal to cubic transformations starting at 495 °C for pure PbTiO3, shifting to lower temperatures with increasing x. For compositions of x ≥ 0.05, a second higher-temperature (∼600 °C) endotherm, and matching dielectric anomaly, were consistently observed, for which there were no structural changes indicated by hot-stage x-ray diffraction. This transformation was speculated to be based on a thermally induced desegregation of B-site cations.

Hardness evolution of Al–Cr–N coatings under thermal load

2008 ◽  
Vol 23 (11) ◽  
pp. 2880-2885 ◽  
Author(s):  
Herbert Willmann ◽  
Paul H. Mayrhofer ◽  
Lars Hultman ◽  
Christian Mitterer
Keyword(s):  
Thermal Load ◽  
Structural Changes ◽  
Single Phase ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Al Content ◽  
Annealing Temperatures ◽  
Transmission Electron

Microstructure and hardness evolution of arc-evaporated single-phase cubic Al0.56Cr0.44N and Al0.68Cr0.32N coatings have been investigated after thermal treatment in Ar atmosphere. Based on a combination of differential scanning calorimetry and x-ray diffraction studies, we can conclude that Al0.56Cr0.44N undergoes only small structural changes without any decomposition for annealing temperatures Ta ⩽ 900 °C. Consequently, the hardness decreases only marginally from the as-deposited value of 30.0 ± 1.1 GPa to 29.4 ± 0.9 GPa with Ta increasing to 900 °C, respectively. The film with higher Al content (Al0.68Cr0.32N) exhibits formation of hexagonal (h) AlN at Ta ⩾ 700 °C, which occurs preferably at grain boundaries as identified by analytical transmission electron microscopy. Hence, the hardness increases from the as-deposited value of 30.1 ± 1.3 GPa to 31.6 ± 1.4 GPa with Ta = 725 °C. At higher temperatures, where the size and volume fraction of the h-AlN phase increases, the hardness decreases to 27.5 ± 1.0 GPa with Ta = 900 °C.

scholarly journals Structural and Mechanical Characteristics of Cu50Zr43Al7 Bulk Metallic Glass Fabricated by Selective Laser Melting

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 775 ◽  
Author(s):  
Xiaoyang Lu ◽  
Mussokulov Nursulton ◽  
Yulei Du ◽  
Wenhe Liao
Keyword(s):  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Selective Laser Melting ◽  
Structural Relaxation ◽  
Mechanical Characteristics ◽  
X Ray Diffraction ◽  
Laser Melting ◽  
Scanning Calorimetry ◽  
Mold Casting ◽  
Induced Changes

In this work, the structural and mechanical characteristics of Cu50Zr43Al7 bulk metallic glass (BMG) fabricated by selective laser melting (SLM) are studied and the impacts from the SLM process are clarified. Cu50Zr43Al7 alloy specimens were manufactured by the SLM method from corresponding gas-atomized amorphous powders. The as-built specimens were examined in terms of phase structure, morphologies, thermal properties and mechanical behavior. The x-ray diffraction and differential scanning calorimetry results showed that structural relaxation and partial crystallization co-exist in the as-fabricated Cu50Zr43Al7 glassy samples. The nano- and micro- hardness and the elastic modulus of the SLM-fabricated Cu50Zr43Al7 BMG were higher than CuZrAl ternary BMGs with similar compositions prepared by conventional mold casting, which can be attributed to the structural relaxation in the former sample. However, the macro compressive strength of the SLM-fabricated Cu50Zr43Al7 BMG was only 1044 MPa mainly due to its porosity. This work suggests that the SLM process induced changes in structural and mechanical properties are significant and cannot be neglected in the fabrication of BMGs.

MEASUREMENTS OF STRUCTURAL RELAXATION IN AMORPHOUS Pd82 Si18: X-RAY DIFFRACTION AND ELECTRICAL RESISTIVITY

1985 ◽  
pp. 683-686 ◽  
Author(s):  
E. Chason ◽  
K.F. Kelton ◽  
P.S. Pershan ◽  
F. Spaepen ◽  
A.H. Weiss ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Structural Relaxation ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Synthesis and Characterization of Conductive Polypyrrole: The Influence of the Oxidants and Monomer on the Electrical, Thermal, and Morphological Properties

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Abdirahman Yussuf ◽  
Mohammad Al-Saleh ◽  
Salah Al-Enezi ◽  
Gils Abraham
Keyword(s):  
Electrical Resistivity ◽  
Room Temperature ◽  
Oxidative Polymerization ◽  
Sodium Dodecyl ◽  
Conductive Polymer ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Structural Formation ◽  
Pyrrole Monomer

Conductive polymer, polypyrrole (PPy), was synthesized by chemical oxidative polymerization technique for a period of four hours at room temperature using pyrrole monomer (mPPy) in aqueous solution. Different oxidants such as ferric chloride (FeCl3) and ammonium persulphate (N2H8S2O8) and surfactant sodium dodecyl sulphate (C12H25NaO4S) were used. The produced PPy samples were characterized by using different techniques such as the electrical resistivity by four probe technique, thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The performance of the oxidants has been investigated and compared. It was found that both oxidants, FeCl3 and N2H8S2O8, have decreased electrical resistivity as a function of temperature, which means increased conductivity. However, FeCl3 has achieved better performance than N2H8S2O8, where it has achieved a lower resistivity of about 60 ohms at room temperature, which indicates higher conductivity of PPy samples with FeCl3 as an oxidant. Similarly, further investigation of FeCl3 oxidant has been conducted by varying its concentration, and its influence on the final properties was reported. It has been observed that the morphology of PPy samples has a significant influence on the conductivity. It was found that 0.1 M and 0.05 M concentrations of FeCl3 oxidant and monomer, respectively, have achieved better thermal stability, which is FeCl3/mPPy ratio of 2 as an optimum value. FTIR and XRD results confirmed the structural formation of polypyrrole from pyrrole monomer during the synthesizing process.

Transformation Behavior of a Ti-Ni-Cu-Fe Alloy

2004 ◽  
Vol 449-452 ◽  
pp. 185-188 ◽  
Author(s):  
Tae Hyun Nam ◽  
Tae Yeon Kim ◽  
Ji Soon Kim ◽  
Seung Baik Kang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Electrical Resistivity ◽  
Resistivity Measurement ◽  
Electrical Resistivity Measurement ◽  
X Ray Diffraction ◽  
Transformation Behavior ◽  
Scanning Calorimetry ◽  
X Ray

Transformation behavior of a Ti-43.0Ni-5.0Cu-2.0Fe(at%) alloy has been investigated by means of electrical resistivity measurement, differential scanning calorimetry and X-ray diffraction. The alloy transformed in three-stage during each cooling and heating procedure. That is, the B2-R-B19-B19' on cooling and the B19'-B19-R-B2 on heating.

Structural, Magnetic and Crystallization Study of Fe-Based Bulk Metallic Glasses

2013 ◽  
Vol 203-204 ◽  
pp. 288-291 ◽  
Author(s):  
Rafał Babilas ◽  
Ryszard Nowosielski ◽  
Wirginia Pilarczyk ◽  
Grzegorz Dercz
Keyword(s):  
Magnetic Properties ◽  
Magnetic Permeability ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Annealing Process ◽  
Bulk Amorphous Alloy ◽  
X Ray Diffraction ◽  
Cast State ◽  
Scanning Calorimetry ◽  
Crystallization Study

The work presents the structural, thermal and magnetic properties analysis of Fe72B20Si4Nb4 bulk metallic glasses in as-cast state and crystallization study of bulk amorphous alloy after annealing process. The studies were performed on bulk metallic glasses in of rods form with diameter of 1,5 and 2 mm. The structure analysis of the samples in as-cast state and phase analysis of studied alloy after annealing process was carried out by the X-ray diffraction (XRD) methods. Mössbauer spectroscopy (MS) was also used to investigate the local structure for studied bulk metallic glasses. Thermal properties associated with glass transition, onset and peak crystallization temperatures was examined by differential scanning calorimetry (DSC). The soft magnetic properties examination of tested material contained initial magnetic permeability and disaccommodation of magnetic permeability.

Sign in / Sign up

Export Citation Format

Share Document