scholarly journals Scanning probe microscopic study of P(VDF-TrFE) based ferroelectric nanocomposites

2021 ◽  
Vol 7 (1) ◽  
pp. 11-16
Author(s):  
Yuliia S. Terekhova ◽  
Dmitry A. Kiselev ◽  
Alexander V. Solnyshkin
Keyword(s):  
Ceramic Powder ◽  
Refraction Index ◽  
Scanning Probe ◽  
Field Frequency ◽  
Light Refraction ◽  
The Matrix ◽  
Local Polarization ◽  
Homogeneous Structures ◽  
Homogeneous Composition ◽  
Titanate Lead

Ceramic and polymer based nanocomponents combine the properties of their constituents, e.g. flexibility, elasticity, polymer reprocessability, hardness typical of glass, wear resistance and high light refraction index. This helps improving many properties of the materials in comparison with the source components. Since recently researchers have been manifesting interest to the properties of complex composite compounds. This is primarily caused by the unique properties of their structures as compared with conventional materials having homogeneous composition. Secondly, this interest is caused by the fact that these compounds may prove to be much cheaper than homogeneous structures provided the physical properties of the composite in a preset range of parameters (temperature, applied field frequency etc.) are identical to those of the respective homogeneous materials. For example, polyvinyl idenfluoride (PVDF) type ferroelectric polymers and copolymers on its basis have found wide application for functional elements of various electromechanic devices in advanced electronics due to their relatively good piezoelectric and pyroelectric properties. The strong random polarization and the formation of polar non-centrosymmetric crystals provide for the high piezoelectric and pyroelectric activity in these crystals. Scanning probe microscopy has been used for study of ferroelectric nanocomposites having different compositions. The matrix specimen for study of local polarization switching at a nanoscale level was vinyl idenfluoride and trifluoroethylene P(VDF-TrFE) copolymer possessing sufficiently high crystallinity. The composite fillers were barium titanate BaTiO3 and deuterized triglycinsulfate DTGS ferroelectric powders and zirconate-titanate lead barium BPZT ceramic powder. We show these materials to show good promise for use in memory cells.

Fundamental Issues in the Sintering of Ceramic Particulate Composites

1991 ◽  
Vol 249 ◽  
Author(s):  
Mohamed N. Rahaman
Keyword(s):  
Ceramic Powder ◽  
Particulate Composites ◽  
Full Density ◽  
Volume Percent ◽  
Ceramic Particulate ◽  
Two Factors ◽  
The Matrix ◽  
Coated Inclusion ◽  
The Subject ◽  
Main Factors

ABSTRACTThe sintering rate of a ceramic powder matrix can be reduced significantly by the presence of rigid inclusions. The factors that lead to this reduced sinterability have been the subject of much debate in the last 5–10 years. Recent work indicate that the reduction in the matrix sinterability is a processing-related problem. The main factors that control the sinterability of ceramic particulate composites include the packing of the matrix immediately surrounding the inclusions and interactions between the inclusions which constrain the matrix. A processing method which avoids the difficulties associated with these two factors is outlined. The method involves the synthesis of coated inclusion particles. Composites containing up to 40 volume percent inclusions can be freely sintered in the solid state to full density.

Enhancing the Nonlinear Optical Properties of Lithium Tetraborate Glass Using Rare Earth Elements and Silver Nanoparticles

NANO ◽  
2020 ◽  
Vol 15 (05) ◽  
pp. 2050064
Author(s):  
M. A. Vallejo ◽  
S. Romero-Servin ◽  
Moisés I. Casillas Alvarez ◽  
Janet A. Elias Angel ◽  
C. Gomez-Solis ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Optical Properties ◽  
Nonlinear Optical ◽  
Emission Spectra ◽  
Refraction Index ◽  
Lithium Tetraborate ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Matrix ◽  
Index Value

In recent years, nonlinear optics field is in constant growth, particularly on the characterization and study of optical properties of glass compounds. In this sense, the plasmonic effect caused by silver nanoparticles (SNP) on the nonlinear optical (NLO) properties of different materials was studied. Furthermore, we report the experimental absorption spectra, the emission spectra, Z-scan measurements in both closed and open apertures and scanning transmission electron microscopy (STEM) to show the morphology of the matrices and the nucleation of SNP. Moreover, some NLO parameters were calculated, such as the NL refraction index and NL coefficient absorption of lithium tetraborate (Li2B4O7) glass activated with rare earths (Dy3+ and Yb3+), as well as study of the effect of different concentrations of SNP. From the results obtained, it has been ascertained that the plasmon resonance caused by the presence of SNP enhances the NL refraction index value, as well as most of its linear optical properties in the matrix of Li2B4O7.

Biocompatibility of CaSiO3 /High-Density Polyethylene Composites Prepared by Hot-Pressing

2006 ◽  
Vol 309-311 ◽  
pp. 1161-1164 ◽  
Author(s):  
Miho Tanuma ◽  
Yoshikazu Kameshima ◽  
Akira Nakajima ◽  
Kiyoshi Okada ◽  
Shigeo Asai ◽  
...  
Keyword(s):  
Hot Pressing ◽  
High Density Polyethylene ◽  
Ceramic Powder ◽  
High Density ◽  
Apatite Formation ◽  
Composite Surface ◽  
Ceramic Particles ◽  
Fast Bone ◽  
The Matrix

We have reported that CaSiO3 ceramics show very fast bone-like apatite formation in simulated body fluid (SBF). However, CaSiO3 ceramics have disadvantages in their mechanical properties and shapability. It is therefore more effective to develop composites of CaSiO3 particles dispersed in a matrix of polymer or metal. Such composites are usually prepared by homogeneously blending the ceramic powder with the matrix component. This method is, however, ineffective for the preparation of biocompatible polymers or metals because only the surfaces containing accidentally-exposed ceramic particles play a role in generating apatite in SBF. It is therefore necessary to add a large volume of ceramic powder and also to abrade the surface to expose more of the ceramic particles. In this study, CaSiO3/high-density polyethylene (HDPE) composites were prepared by hot-pressing to introduce surface CaSiO3 particles and their biocompatibilities were evaluated under in vitro conditions using SBF. CaSiO3 powders were spread on a HDPE plate and hot-pressed at 140oC and 4.9-14.7 MPa for 2 min. The composite sample (about 10×10×1 mm3 in size) was immersed in 30ml SBF (sample/solution ratio of 2.5 g/l) at 36.5oC. After 14 days soaking, the apatite product particles covered most of the composite surface and formed apatite layers. Bone-like apatite particles were formed only on the surface regions containing exposed CaSiO3 particles but no apatite was formed on the CaSiO3 particles buried in the HDPE matrix. The results show that this surface deposition method is very effective in developing biocompatibility in the composites using very small amounts of CaSiO3 powder (about <1 %v) compared with results reported for hydroxyapatite and AW glass-ceramic powders (requiring about 40 %v). It is also found that the inhomogeneous state of the CaSiO3 particles in the surface of the present composites strongly influences their biocompatibility. It will be necessary to improve the homogeneity of CaSiO3 dispersion in the surface of the composites to achieve a more uniform surface apatite layer.

The Effect of Titanium Addition on Microstructure and Properties of Laves Phase Cr2Nb Alloy Synthesized by Hot Pressing

2011 ◽  
Vol 328-330 ◽  
pp. 1102-1108 ◽  
Author(s):  
Xuan Xiao ◽  
Shi Qiang Lu ◽  
Xian Juan Dong ◽  
Ming Gang Huang ◽  
Jun Wei Liu
Keyword(s):  
Fracture Toughness ◽  
Mechanical Alloying ◽  
Hot Pressing ◽  
Laves Phase ◽  
Nominal Composition ◽  
Second Phase ◽  
Titanium Addition ◽  
Fine Grain ◽  
The Matrix ◽  
Homogeneous Composition

The composite materials with a nominal composition of Cr2Nb-24wt.%Ti were fabricated by mechanical alloying followed by hot pressing. The microstructures and properties were investigated on the composites contained with Laves phase prepared through 20 hours mechanical alloying of chromium, niobium and titanium elemental powders and hot pressing at 1250°C for half an hour. The results indicate that the near full-dense Laves phase Cr2(Nb,Ti) based alloy with homogeneous composition and microstructure is obtained by mechanical alloying and hot pressing techniques. The dispersed soft second phase Nb solid solutions with the fine grain size less than 1μm are distributed uniformly on the matrix. The sample has a relative density of 99%, fracture toughness of 5.32MPa•m1/2 and compress strength of 2080MPa. Due to the effect of fine-grain and alloying addition, the toughening of the Cr2(Nb,Ti) based alloy has been fully realized.

scholarly journals Исследования проводящих и сегнетоэлектрических свойств BZT-пленок

2020 ◽  
Vol 90 (12) ◽  
pp. 2159
Author(s):  
Е.В. Гущина ◽  
Б.Р. Бородин ◽  
В.А. Шаров ◽  
В.В. Осипов ◽  
С.И. Павлов ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Scanning Probe Microscopy ◽  
Coercive Field ◽  
Scanning Probe ◽  
Residual Polarization ◽  
Probe Microscopy ◽  
Local Polarization

The local polarization processes in thin BaTi1-xZrxO3 films were investigated by contact conducting scanning probe microscopy and piezoresponse microscopy. A relationship between the direction of the created domains and the magnitude of the flowing currents is established. The value of the residual polarization is found, and the hysteresis loop is measured using scanning probe microscopy as well as the values ​​of the piezomodule dzz and the value of the coercive field Ec for these films are determined.

Microstructure and Deposition Relations in Alumina Particle Strengthened Ni-W Matrix Composites

2012 ◽  
Vol 186 ◽  
pp. 234-238 ◽  
Author(s):  
Paulina Indyka ◽  
Ewa Beltowska-Lehman ◽  
Magdalena Bieda ◽  
Jerzy Morgiel ◽  
Leszek Tarkowski
Keyword(s):  
Composite Coatings ◽  
Metallic Matrix ◽  
Electrolyte Solutions ◽  
Ultrasonic Field ◽  
Matrix Composites ◽  
Field Frequency ◽  
Plating Bath ◽  
Electron Microscopies ◽  
The Matrix ◽  
Average Size

The nanostructured Ni-W/Al2O3 composite coatings were prepared by electrodeposition technique on ferritic steel substrates from aqueous electrolyte solutions containing ultrafine alumina particles in suspension. The effects of plating parameters like current density, inert particle concentration in plating bath and ultrasonic field frequency on the incorporation of α-Al2O3 particles (TM-DAR Taimicron) into an Ni-W matrix were investigated. The MMC coatings microstructure, phase and chemical composition were studied by means of scanning (E-SEM FEI XL-30) and transmission (TECNAI G2 SuperTWIN) electron microscopies, as well as XRD measurements (Bruker D8 Discover). SEM and TEM observations of composite cross-section microstructure showed that the presence of ultrasounds considerably reduces the particles agglomeration and enables a uniform distribution of particles in the Ni-W matrix. The electron diffraction pattern analysis revealed that the composite metallic matrix consists of an α-Ni(W) solid solution. The matrix was characterized by quasifibrous, nanocrystalline grains of an average size about 10 nm.

scholarly journals Polarization reversal by tip of scanning probe microscope in SBN

2016 ◽  
Vol 1 (1) ◽  
pp. 115 ◽  
Author(s):  
E.A. Neradovskaya ◽  
M.M. Neradovskiy ◽  
V.V. Fedorovyh ◽  
A.P. Turygin ◽  
V.Ya. Shur ◽  
...  
Keyword(s):  
Opposite Sign ◽  
Scanning Probe Microscope ◽  
Scanning Probe ◽  
Polarization Reversal ◽  
Practical Applications ◽  
Domain State ◽  
Initial Domain ◽  
Circular Domains ◽  
Probe Microscope ◽  
Local Polarization

<p>We present the results of experimental study of the influence of initial domain state on the shape and size of isolated domains created by the conductive tip of scanning probe microscope during local polarization reversal in relaxor ferroelectric strontium barium niobate doped with nickel and cerium. The domain radius was found to increase with increasing voltage and time and depend on the initial polarization direction. Circular domains of the opposite sign were found to appear due to polarization backswitching. The obtained results can be used for practical applications of domain and domain wall engineering in ferroelectrics.</p>

Crystalloid Inclusions in Hepatocyte Mitochondria and Their Similarity to Cytoplasmic Crystalloids

1974 ◽  
Vol 32 ◽  
pp. 198-199
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo
Keyword(s):  
Liver Disease ◽  
Alcoholic Liver Disease ◽  
Special Interest ◽  
Structural Variations ◽  
Mitochondrial Alterations ◽  
The Matrix ◽  
Crystalloid Inclusions ◽  
Liver Biopsies

Mitochondrial alterations were studied in 25 liver biopsies from patients with alcoholic liver disease. Of special interest were the morphologic resemblance of certain fine structural variations in mitochondria and crystalloid inclusions. Four types of alterations within mitochondria were found that seemed to relate to cytoplasmic crystalloids.Type 1 alteration consisted of localized groups of cristae, usually oriented in the long direction of the organelle (Fig. 1A). In this plane they appeared serrated at the periphery with blind endings in the matrix. Other sections revealed a system of equally-spaced diagonal lines lengthwise in the mitochondrion with cristae protruding from both ends (Fig. 1B). Profiles of this inclusion were not unlike tangential cuts of a crystalloid structure frequently seen in enlarged mitochondria described below.

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