scholarly journals Enhancement of the Magnetoelectric Effect in PZT-Ni Ferrite Composites Using Post Sintering Thermal Treatment

2021 ◽  
Author(s):  
Rashed Adnan Islam
Keyword(s):  
Thermal Treatment ◽  
Nickel Ferrite ◽  
Ferromagnetic Material ◽  
Composite Powders ◽  
Compact Structure ◽  
Tem Analysis ◽  
Voltage Coefficient ◽  
Average Grain Size ◽  
The Matrix ◽  
Ferrite Composites

In this chapter, the piezoelectric and magnetoelectric properties of Pb (Zr0.52T0.48)O3–X NiFe1.9Mn0.1O4 (PZT-NFM, where X ranges from 3 to 10%) were investigated along with SEM and TEM analysis. Post sintering thermal treatment (annealing and aging) was introduced to enhance the piezoelectric and magnetoelectric property of the composites. The density was found around 7.6–7.8 gm/cc. The piezoelectric constant d33 and the voltage constant were found to be decreased with increasing magnetic particle from 3–10%. Experimental results indicated that the magnetoelectric voltage coefficient (dE/dH) increases with increasing percentage of Nickel Ferrite (~35 for 3% NF to 140 mV/Oe. cm for 10% NF at 1125°C). The samples, which were annealed and aged after sintering show as high as 50% (140 to 220 mV/cm Oe) increase in dE/dH coefficient. This is due to the increase in resistivity due to better homogeneity. The H-M curve of the composite powders show that the PZT-NFM is a ferromagnetic material as well. The SEM investigation shows very compact structure with average grain size around 150 nm and some areas of the NF rich phase. The X-ray mapping shows that the NF is distributed in the big grains of the matrix and after annealing it homogenizes.

TEM Analysis of Long-Period Polytypes in SiC—S

1976 ◽  
Vol 34 ◽  
pp. 630-631
Author(s):  
S. Shinozaki ◽  
J. W. Sprys
Keyword(s):  
Electron Diffraction ◽  
Isothermal Annealing ◽  
Tem Analysis ◽  
Long Period ◽  
Transmission Electron ◽  
Average Grain Size ◽  
High Resolution Tem ◽  
Structural Lattice ◽  
The Stability ◽  
Continuous Curves

In reaction sintered SiC (∽ 5um average grain size), about 15% of the grains were found to have long-period structures, which were identifiable by transmission electron microscopy (TEM). In order to investigate the stability of the long-period polytypes at high temperature, crystal structures as well as microstructural changes in the long-period polytypes were analyzed as a function of time in isothermal annealing.Each polytype was analyzed by two methods: (1) Electron diffraction, and (2) Electron micrograph analysis. Fig. 1 shows microdensitometer traces of ED patterns (continuous curves) and calculated intensities (vertical lines) along 10.l row for 6H and 84R (Ramsdell notation). Intensity distributions were calculated based on the Zhdanov notation of (33) for 6H and [ (33)3 (32)2 ]3 for 84R. Because of the dynamical effect in electron diffraction, the observed intensities do not exactly coincide with those intensities obtained by structure factor calculations. Fig. 2 shows the high resolution TEM micrographs, where the striped patterns correspond to direct resolution of the structural lattice periodicities of 6H and 84R structures and the spacings shown in the figures are as expected for those structures.

Tem analysis of multiple-energy arsenic implanted and Rta'd silicon

1987 ◽  
Vol 45 ◽  
pp. 246-247
Author(s):  
R.A. Herring
Keyword(s):  
Device Fabrication ◽  
High Concentration ◽  
Tem Analysis ◽  
Defect Clusters ◽  
High Fluences ◽  
Small Defect ◽  
Before And After ◽  
The Matrix ◽  
The Difference ◽  
Factor Type

Rapid thermal annealing (RTA) of ion-implanted Si is important for device fabrication. The defect structures of 2.5, 4.0, and 6.0 MeV As-implanted silicon irradiated to fluences of 2E14, 4E14, and 6E14, respectively, have been analyzed by electron diffraction both before and after RTA at 1100°C for 10 seconds. At such high fluences and energies the implanted As ions change the Si from crystalline to amorphous. Three distinct amorphous regions emerge due to the three implantation energies used (Fig. 1). The amorphous regions are separated from each other by crystalline Si (marked L1, L2, and L3 in Fig. 1) which contains a high concentration of small defect clusters. The small defect clusters were similar to what had been determined earlier as being amorphous zones since their contrast was principally of the structure-factor type that arises due to the difference in extinction distance between the matrix and damage regions.

The microstructure change of low-carbon electrical steels by residual aluminum

1989 ◽  
Vol 47 ◽  
pp. 286-287
Author(s):  
C.K. Hou ◽  
C.T. Hu ◽  
Sanboh Lee
Keyword(s):  
Annealing Treatment ◽  
Low Carbon ◽  
Electrical Steels ◽  
Vacuum Degassing ◽  
Spherical Inclusions ◽  
Residual Aluminum ◽  
Average Grain Size ◽  
The Matrix ◽  
Fine Size ◽  
To Come

The fully processed low-carbon electrical steels are generally fabricated through vacuum degassing to reduce the carbon level and to avoid the need for any further decarburization annealing treatment. This investigation was conducted on eighteen heats of such steels with aluminum content ranging from 0.001% to 0.011% which was believed to come from the addition of ferroalloys.The sizes of all the observed grains are less than 24 μm, and gradually decrease as the content of aluminum is increased from 0.001% to 0.007%. For steels with residual aluminum greater than 0. 007%, the average grain size becomes constant and is about 8.8 μm as shown in Fig. 1. When the aluminum is increased, the observed grains are changed from the uniformly coarse and equiaxial shape to the fine size in the region near surfaces and the elongated shape in the central region. SEM and EDAX analysis of large spherical inclusions in the matrix indicate that silicate is the majority compound when the aluminum propotion is less than 0.003%, then the content of aluminum in compound inclusion increases with that in steel.

Using crystallographic symmetry in diffraction and contrast analysis

1989 ◽  
Vol 47 ◽  
pp. 504-505
Author(s):  
U. Dahmen ◽  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
High Symmetry ◽  
Two Phase ◽  
Tem Analysis ◽  
Crystallographic Symmetry ◽  
The Matrix ◽  
Contrast Analysis ◽  
Practical Tool ◽  
Convergent Beam ◽  
Beam Diffraction

Despite the increased use of convergent beam diffraction, symmetry concepts in their more general form are not commonly applied as a practical tool in electron microscopy. Crystal symmetry provides an abundance of information that can be used to facilitate and improve the TEM analysis of crystalline solids. This paper draws attention to some aspects of symmetry that can be put to practical use in the analysis of structures and morphologies of two-phase materials.It has been shown that the symmetry of the matrix that relates different variants of a precipitate can be used to determine the axis of needle- or lath-shaped precipitates or the habit plane of plate-shaped precipitates. By tilting to a special high symmetry orientation of the matrix and by measuring angles between symmetry-related variants of the precipitate it is possible to find their habit from a single micrograph.

Morphology and Mechanical Properties of Polyethylene Terephthalate/Ethylene Propylene Diene Monomer (PET/EPDM) in the Presence of Nanoclay

2020 ◽  
Vol 57 (3) ◽  
pp. 249-259
Author(s):  
Baifen Liu ◽  
Mohammad Mirjalili ◽  
Peiman Valipour ◽  
Sajad Porzal ◽  
shirin Nourbakhsh
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Thermal Destruction ◽  
Processing Temperature ◽  
Tem Analysis ◽  
Maximum Stiffness ◽  
Cloisite 30B ◽  
Nano Clay ◽  
The Matrix ◽  
Sample Maximum

This research deals with the mechanical properties, microstructure, and interrelations of triple nanocomposite based on PET/EPDM/Nanoclay. These properties were examined in different percentages of PET/EPDM blend with compatibilizer (Styrene-Ethylene/Butylene-Styrene)-G-(Maleic anhydrate) (SEBS-g-MAH). Results showed that the addition of 15% SEBS-g-MAH improved the toughness and impact strength of this nanocomposite. SEM micrographs indicated the most stable fuzzy microstructure in a 50/50 mixture of scattered phases of EPDM/SEBS-g-MAH. The effects of percentages of 1, 3, 5, 7 nanoclay Cloisite 30B (C30B) on the improvement of the properties were evaluated. With the addition of nano clay, the toughness and impact strength was reduced. Thermal destruction of nanoclay in processing temperature led to the decreasing dispersion of clay plates in the matrix and a reduction in the distances of nano clay plates in the composite compared to pure nano clay. XRD and TEM analysis was used to demonstrate the results. By adding 1% of nanoclay to the optimal sample, maximum stiffness, and Impact strength, among other nanocomposites, was achieved.

scholarly journals Effect of Vanadium Reinforcement on the Microstructure and Mechanical Properties of Magnesium Matrix Composites

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 806
Author(s):  
Liqing Sun ◽  
Shuai Sun ◽  
Haiping Zhou ◽  
Hongbin Zhang ◽  
Gang Wang ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Milling Process ◽  
Mg Alloy ◽  
Matrix Composites ◽  
Magnesium Matrix Composites ◽  
Pinning Effect ◽  
Average Grain Size ◽  
The Matrix ◽  
Hot Press Sintering

In this work, vanadium particles (VP) were utilized as a novel reinforcement of AZ31 magnesium (Mg) alloy. The nanocrystalline (NC) AZ31–VP composites were prepared via mechanical milling (MM) and vacuum hot-press sintering. During the milling process, the presence of VP contributed to the cold welding and fracture mechanism, resulting in the acceleration of the milling process. Additionally, increasing the VP content accelerated the grain refinement of the matrix during the milling process. After milling for 90 h, the average grain size of AZ31-X wt % Vp (X = 5, 7.5, 10) was refined to only about 23 nm, 19 nm and 16 nm, respectively. In the meantime, VP was refined to sub-micron scale and distributed uniformly in the matrix, exhibiting excellent interfacial bonding with the matrix. After the sintering process, the average grain size of AZ31-X wt % VP (X = 5, 7.5, 10) composites still remained at the NC scale, which was mainly caused by the pinning effect of VP. Besides that, the porosity of the sintered composites was no more than 7.8%, indicating a good densification effect. As a result, there was little difference between the theoretical and real density. Compared to as-cast AZ31 Mg alloy, the microhardness of sintered AZ31-X wt % VP (X = 5, 7.5, 10) composites increased by 65%, 87% and 96%, respectively, owing to the strengthening mechanisms of grain refinement strengthening, Orowan strengthening and load-bearing effects.

scholarly journals Novel Polyimide/Copper-Nickel Ferrite Composites with Tunable Magnetic and Dielectric Properties

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1646
Author(s):  
Corneliu Hamciuc ◽  
Mihai Asandulesa ◽  
Elena Hamciuc ◽  
Tiberiu Roman ◽  
Marius Andrei Olariu ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Nickel Ferrite ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Broadband Dielectric Spectroscopy ◽  
Copper Nickel ◽  
Low Dielectric ◽  
Magnetic Remanence ◽  
Polyimide Matrix ◽  
Ferrite Composites

Heat-resistant magnetic polymer composites were prepared by incorporating cerium-doped copper-nickel ferrite particles, having the general formula Ni1-xCuxFe1.92Ce0.08O4 (x: 0.0, 0.3, 0.6, 1.0), into a polyimide matrix. The effects of particle type and concentration on the thermal, magnetic, and electrical properties of the resulting composites were investigated. The samples were characterized by FTIR, scanning electron microscopy, X-ray diffractometry, thermogravimetric analysis, differential scanning calorimetry, vibrating sample magnetometer, and broadband dielectric spectroscopy. The composites exhibited high thermal stability, having initial decomposition temperatures between 495 and 509 °C. Saturation magnetization (Ms), magnetic remanence (Mr), and coercivity (Hc) were found in range of 2.37–10.90 emu g−1, 0.45–2.84 emu g−1, and 32–244 Oe, respectively. The study of dielectric properties revealed dielectric constant values of 3.0–4.3 and low dielectric losses of 0.016–0.197 at room temperature and a frequency of 1 Hz.

Recrystallization in Ultra-Fine Grain Structures of AA3104 Alloy Processed by ECAP and HPT

2012 ◽  
Vol 715-716 ◽  
pp. 346-353
Author(s):  
H. Paul ◽  
T. Baudin ◽  
K. Kudłacz ◽  
A. Morawiec
Keyword(s):  
High Pressure Torsion ◽  
Deformation Mode ◽  
Second Phase ◽  
Orientation Measurement ◽  
Angular Pressing ◽  
Second Phase Particles ◽  
Average Grain Size ◽  
The Matrix ◽  
Electron Microscopes ◽  
Different Strains

The objective of this study was to determine the effect of deformation mode on recrystallization behavior of severely deformed material. Commercial purity AA3104 aluminum alloy was deformed via high pressure torsion and equal channel angular pressing to different strains and then annealed to obtain the state of partial recrystallization. The microstructure and the crystallographic texture were analysed using scanning and transmission electron microscopes equipped with orientation measurement facilities. The nucleation of new grains was observed in bulk recrystallized samples and during in-situ recrystallization in the transmission microscope. Irrespective of the applied deformation mode, a large non-deformable second phase particles strongly influenced strengthening of the matrix through deformation zones around them. It is known that relatively high stored energy stimulates the nucleation of new grains during the recrystalization. In most of the observed cases, the growth of recrystallized grains occurred by the coalescence of neighboring subcells. This process usually led to nearly homogeneous equiaxed grains of similar size. The diameter of grains in the vicinity of large second phase particles was only occasionally significantly larger than the average grain size. Large grains were most often observed in places far from the particles. TEM orientation mapping from highly deformed zones around particles showed that orientations of new grains were not random and only strictly defined groups of orientations were observed.

Development of Ni/h-BN Self-Lubricating Composite Powder by High-Energy Ball Milling

2016 ◽  
Vol 869 ◽  
pp. 277-282
Author(s):  
Moisés Luiz Parucker ◽  
César Edil da Costa ◽  
Viviane Lilian Soethe
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
Solid Lubricants ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Second Phase ◽  
Average Particle ◽  
Composite Powders ◽  
The Matrix ◽  
Energy Ball

Solid lubricants have had good acceptance when used in problem areas where the conventional lubricants cannot be applied: under extreme temperatures, high charges and in chemically reactive environments. In case of materials manufactured by powder metallurgy, particles of solid lubricants powders can be easily incorporated to the matrix volume at the mixing stage. In operation, this kind of material provides a thin layer of lubricant that prevents direct contact between the surfaces. The present study aimed at incorporating particles of second phase lubricant (h-BN) into a matrix of nickel by high-energy ball milling in order to obtain a self-lubricating composite with homogeneous phase distribution of lubricant in the matrix. Mixtures with 10 vol.% of h-BN varying the milling time of 5, 10, 15 and 20 hours and their relationship ball/powder of 20:1 were performed. The effect of milling time on the morphology and microstructure of the powders was studied by X-ray diffraction, SEM and EDS. The composite powders showed reduction in average particle size with increasing milling time and the milling higher than 5 hours resulted in equiaxial particles and the formation of nickel boride.

Research of the process of synthesis and properties of the obtained metal-matrix composite powders of the Ti/tib2 system

2021 ◽  
pp. 66-73
Author(s):  
M. E. Goshkoderya ◽  
T. I. Bobkova ◽  
M. V. Staritsyn
Keyword(s):  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Metal Matrix ◽  
Composite Powders ◽  
Optimal Ratio ◽  
The Matrix ◽  
Series Of Experiments ◽  
Sprayed Coatings

The paper proposes a method for preparing composite powders of the Ti/TiB2 system, studies the properties of the obtained composite powders, and also shows a series of experiments on its microplasma spraying. The properties of the sprayed coatings were investigated. On its basis the optimal ratio of the matrix and reinforcing components was established in order to increase significantly the hardness of the sprayed coatings.

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