Evolution of Magnetism in CaO-SiO2-P2O5-Na2O-Fe2O3 Bioglass Ceramics

2008 ◽  
Vol 587-588 ◽  
pp. 171-174
Author(s):  
Rajendra Kumar Singh ◽  
A. Perumal ◽  
Govind P. Kothiyal ◽  
A. Srinivasan
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Structural Investigation ◽  
Magnetic Measurements ◽  
Magnetic Behavior ◽  
Soft Magnetic Materials ◽  
Soft Magnetic ◽  
Melt Quenching ◽  
Heat Treated ◽  
Magnetite Phase

We report the evolution of magnetism in bioglass ceramics 41CaO.(52-x)SiO2.4P2O5. xFe2O3.3Na2O (2 ≤ x ≤ 10 mole % Fe2O3) prepared by melt quenching technique followed by heat treatment at 1050 oC. The structural investigation revealed the presence of magnetite phase in the heat treated samples with x ≥ 2 mole % Fe2O3. Room temperature magnetic measurements showed a very weak ferrimagnetic behaviour for the sample with x = 2 mole % of Fe2O3. Samples with x > 2 mole % of Fe2O3 exhibited magnetic behavior similar to soft magnetic materials with low coercivity. The evolution of magnetic properties in these samples as a function of Fe2O3 molar concentration is correlated with the amount of magnetite phase present in them.

scholarly journals Influence of Annealing Temperature on the Crystallization Kinetics of Fe82Si8B10 Amorphous Ribbon

2020 ◽  
Vol 11 (1) ◽  
pp. 107-112
Author(s):  
A Said Sikder ◽  
SD Nath ◽  
SS Sikder
Keyword(s):  
Crystallization Kinetics ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Amorphous Ribbon ◽  
Primary Crystallization ◽  
Soft Magnetic Materials ◽  
Power Transformers ◽  
Soft Magnetic ◽  
Potential Applications ◽  
Kinetics Of

Amorphous soft magnetic materials have significant potential applications in specialist power transformers and in inductive devices. With the composition of Fe82Si8B10, 82% of the transition metals Fe and about 18% of metalloid or glass-former elements like B and Si are strongly magnetic at room temperature and offer dynamic opportunities for engineering applications. The crystallization kinetics has been studied by differential thermal analysis (DTA). The sample was annealed in a controlled way in the temperature range of 350-450°C at constant annealing time one hour. The kinetics of primary crystallization α-Fe(Si) phase and secondary crystallization Fe2B phase was studied as affected due to temperature. The sample annealed at 350oC temperature is almost unchanged which is still lower than that of primary crystallization temperature but the same condition when sample annealed at 450°C completely shows that the primary crystallization α-Fe(Si) phase has vanished and crystallization event took place to a good extent. Journal of Engineering Science 11(1), 2020, 107-112

Preparation of Magnetically Soft, Highly-Densified Fe Cluster-Assembled Films by Impact Cluster Deposition

2006 ◽  
Vol 11-12 ◽  
pp. 595-598
Author(s):  
Dong Liang Peng ◽  
K. Sumiyama ◽  
H. Yamada ◽  
Takehiko Hihara ◽  
T. Uchida
Keyword(s):  
Room Temperature ◽  
Magnetic Behavior ◽  
Cluster Beam ◽  
Frequency Range ◽  
Soft Magnetic ◽  
Size Change ◽  
Gas Condensation ◽  
Cluster Deposition ◽  
The Impact ◽  
High Cluster

Highly-densified Fe cluster-assembled films were obtained at room temperature by an energetic cluster deposition. Fe clusters were produced using a plasma-gas-condensation (PGC)-type cluster deposition apparatus with a high cluster productivity. Ionized clusters in a cluster beam were electrically accelerated and directly deposited onto a substrate together with neutral clusters from the same cluster source. By increasing the impact energy of the ionized clusters up to about 1 eV/atom, the obtained cluster-assemblies have packing fractions higher than 0.8 without any serious size change, and result in a soft magnetic behavior up to a frequency range of few hundred MHz.

Coercivity Mechanism in Hard and Soft Sintered Magnetic Materials

2014 ◽  
Vol 802 ◽  
pp. 563-568 ◽  
Author(s):  
Marcos Flavio de Campos
Keyword(s):  
Grain Size ◽  
Domain Wall ◽  
Magnetic Materials ◽  
Wall Thickness ◽  
Magnetic Behavior ◽  
Soft Magnetic Materials ◽  
High Coercivity ◽  
Soft Magnetic ◽  
Hard Magnetic Materials ◽  
Wall Movement

The coercivity in soft and hard magnetic materials has different origin. The high coercivity of barium ferrite, SmCo5, Sm2Co17or Nd2Fe14B is due to high magnetocrystalline anisotropy, and the processing aims very small grain size (nanocrystalline). In the case of soft magnetic materials, the coercivity has origin in defects that are able to stop domain wall movement, as for example grain boundaries, inclusions or dislocations. Soft magnetic materials in general present large domain wall thickness (thousands of Angstroms for pure iron), whereas domain wall thickness is ~ 50 Angstroms for SmCo5and Nd2Fe14B. The differences between hard and soft magnetic behavior are commented and discussed. The domain wall energy and thickness can be used as parameters for classifying soft and hard magnetic behavior. Other examples of soft magnetic materials are the amorphous alloys and the nanocrystalline soft magnetic materials with grain size very below the single domain particle size. The soft behaviour in amorphous and soft nanocrystalline materials is also discussed.

Enhancement of Long-Wavelength Photoluminescence Due to Heat-Treatment in Si-Doped GaAs

1992 ◽  
Vol 262 ◽  
Author(s):  
M. Suezawa ◽  
A. Kasuya ◽  
Y. Nishina ◽  
K. Sumino
Keyword(s):  
Heat Treatment ◽  
Radiative Recombination ◽  
Room Temperature ◽  
Excitation Spectra ◽  
Long Wavelength ◽  
Heat Treated ◽  
Intense Luminescence ◽  
Si Doped

ABSTRACTHighly officient radiative recombination even at room temperature was found at a wavelength of about 1.3 μm in heat-treated Si-doped GaAs. The range of Si concentrations and the condition of heat-treatment to yield this intense luminescence were determined. Excitation spectra of the PL lines suggest that such PL lines are related to pairs of Si-donor and Si- acceptor and such pairs combined with gallium vacancies.

scholarly journals Влияние термообработки на электрические характеристики полуизолирующих слоев, полученных с помощью облучения n-SiC высокоэнергетическими ионами аргона

2018 ◽  
Vol 44 (6) ◽  
pp. 11 ◽  
Author(s):  
П.А. Иванов ◽  
А.С. Потапов ◽  
М.Ф. Кудояров ◽  
М.А. Козловский ◽  
Т.П. Самсонова
Keyword(s):  
Heat Treatment ◽  
Silicon Carbide ◽  
Room Temperature ◽  
High Energy ◽  
Room Temperature Resistivity ◽  
Electrical Characteristics ◽  
Near Surface ◽  
Heat Treated ◽  
Argon Ions ◽  
Temperature Resistivity

AbstractIrradiation of crystalline n -type silicon carbide ( n -SiC) with high-energy (53-MeV) argon ions was used to create near-surface semi-insulating ( i -SiC) layers. The influence of subsequent heat treatment on the electrical characteristics of i -SiC layers has been studied. The most high-ohmic ion-irradiated i -SiC layers with room-temperature resistivity of no less than 1.6 × 10^13 Ω cm were obtained upon the heat treatment at 600°C, whereas the resistivity of such layers heat-treated at 230°C was about 5 × 10^7 Ω cm.

scholarly journals Hydrogen Detection with SAW Polymer/Quantum Dots Sensitive Films

Sensors ◽  
2019 ◽  
Vol 19 (20) ◽  
pp. 4481 ◽  
Author(s):  
Izabela Constantinoiu ◽  
Cristian Viespe
Keyword(s):  
Heat Treatment ◽  
Quantum Dots ◽  
Room Temperature ◽  
Limit Of Detection ◽  
Composite Films ◽  
High Specific Surface Area ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Heat Treated ◽  
Gas Molecules

Regarding the use of hydrogen as a fuel, it is necessary to measure its concentration in air at room temperature. In this paper, sensitive composite films have been developed for surface acoustic wave (SAW) sensors, using quantum dots (QDs) and polymers. Si/SiO2 QDs were used due to having a high specific surface area, which considerably improves the sensitivity of the sensors compared to those that only have a polymer. Si/SiO2 QDs were obtained by laser ablation and analyzed by X-ray diffraction and transmission electron microscopy (TEM). Two types of polymers were used: polydimethylsiloxane (PDMS) and polymethylmethacrylate (PMMA). Polymer and polymer with QDs compositions were deposited on the sensor substrate by drop casting. A heat treatment was performed on the films at 80 °C with a thermal dwell of two hours. The sensors obtained were tested at different hydrogen concentrations at room temperature. A limit of detection (LOD) of 452 ppm was obtained by the sensor with PDMS and Si/SiO2 QDs, which was heat treated. The results demonstrated the potential of using QDs to improve the sensitivity of the SAW sensors and to achieve a heat treatment that increases its adsorption capacity of the gas molecules.

Platinum-TiO2 (Rutile) Substrate Interaction During Cyclic Oxidation-Reduction Heat-Treatment

1981 ◽  
Vol 39 ◽  
pp. 72-73
Author(s):  
S. Shinozaki ◽  
W. T. Donlon ◽  
A. H. Meitzler
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Treatment Procedure ◽  
Substrate Interaction ◽  
Reducing Atmosphere ◽  
Oxidation Reduction ◽  
Heat Treated ◽  
Pt Electrodes ◽  
The Matrix ◽  
Tio2 Rutile

When polycrystalline TiO2 (rutile) pellets (∼1mm in thickness and ∼3 mm in diameter), dispersed with Pt particles to act as a catalyst, were heat-treated under certain conditions involving an applied electric field, new unusual microstructures were formed. The heat-treatment procedure was, as follows: 1) apply 1 volt dc field between two Pt electrodes inbedded into the pellet, 2) heat the sample to 750°C and begin cycling the sample between oxydizing (4% O2 in N2) and reducing (2% CO in N2) atmospheres at a rate of several cycles per hour, 3) lower the temperature to 600°C while continually cycling (200 cycle), and, 4) cool the sample to room temperature under the reducing atmosphere (1). The pellet was ion milled to a proper electron transparency and examined by means of a Siemens EM102 and a Philips EM400 TEM-STEM microscope.Some TiO2 grains in this sample exhibited no resolvable defect structure, except that the matrix appeared to be strained due to small defects (Fig. la).

THE EFFECT OF LOW TEMPERATURES UPON THE IMPACT RESISTANCE OF STEEL CASTINGS

1930 ◽  
Vol 2 (5) ◽  
pp. 327-340
Author(s):  
R. W. Moffatt
Keyword(s):  
Heat Treatment ◽  
Low Temperatures ◽  
Room Temperature ◽  
Freezing Point ◽  
High Carbon Steel ◽  
Impact Resistance ◽  
Nickel Steel ◽  
Heat Treated ◽  
Steel Castings ◽  
The Impact

The investigation deals with the effect of low temperatures on the impact resistance of steel castings and forgings. Low, medium and high carbon steel castings and a few alloys of vanadium, nickel, and vanadium-nickel steel castings were examined. The metals were subjected to low temperatures, both before and after heat treatment. The temperatures for the tests varied from room temperatures to temperatures well below 0° F., so as to extend below the ordinary atmospheric range of temperatures found in northern climates.It was found that the impact resistances of the metals decreased for temperatures below the freezing point. For specimens, not heat treated, the impact resistance at − 40° F. may be only one-third to one-half of that at room temperature. Heat treatment increases the impact resistance at room temperatures and temperatures below the freezing point. The impact resistance at − 40° F. for the heat-treated metal compared favorably with the impact resistance of the untreated metal at room temperature, 68° F. Heat treatment may slightly lower the yield point and the ultimate tensile strength, but it increases the ductility and the impact resistance of the metal. By proper heat treatment of steel castings the impact resistance at − 40° F. may be brought over 300% higher than that of the untreated metal at that temperature.

Cutoff Frequency Study on Nanocrystalline FeNbB Thin Films

2012 ◽  
Vol 465 ◽  
pp. 72-75
Author(s):  
Xiao Long Jiang ◽  
Y.J. Yao ◽  
M. Lai ◽  
K. Peng ◽  
Y.W. Du
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Ion Beam ◽  
Cutoff Frequency ◽  
Magnetic Behavior ◽  
Soft Magnetic Properties ◽  
Ion Beam Sputtering ◽  
Soft Magnetic ◽  
Beam Sputtering

A series of nanocrystalline FeNbB films were fabricated using ion-beam sputtering technique from FeNbB target. Pieces of these films were annealed for 1 hour at various temperatures up to 5730C. Room temperature soft magnetic properties of these films were measured. The influence of microstructure on magnetic behavior in nanocrystalline FeNbB films is investigated in a series of specimens with different film’s thickness. For the sample 120nm and 5000C annealed, cutoff frequency was found to be 5E7 Hz, which has the μf0=5E10.

IN-SITU Analysis Of The Microstructure of Thermally Treated Thin Copper Films

1993 ◽  
Vol 309 ◽  
Author(s):  
J. Nucci ◽  
H. Neves ◽  
Y. Shacham ◽  
E. Eisenbraun ◽  
B. Zheng ◽  
...  
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Room Temperature ◽  
Thermal Evolution ◽  
Electron Beam Evaporation ◽  
Copper Films ◽  
Tem Analysis ◽  
Heat Treated ◽  
Baseline Information

AbstractCopper thin films were deposited by sputtering, electron beam evaporation, and electroless plating onto nitride membranes for TEM analysis. The samples were heat treated in-situ from room temperature to 600 °C for structural and chemical analysis. The as-deposited and heat treated microstructures were investigated. Orientation changes with heat treatment and reactions among the sample layers were analyzed by electron diffraction. This work provides baseline information for a study of the thermal evolution of copper lines.

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