Raman Imaging and Thermal Expansion of Highly Textured Pb(Mg1/3Nb2/3)O3-PbTiO3 Piezoelectric Ceramics

2004 ◽  
Vol 855 ◽  
Author(s):  
Philippe Colomban ◽  
Mai Pham-Thi
Keyword(s):  
Thermal Expansion ◽  
Dielectric Properties ◽  
Single Crystals ◽  
Short Range ◽  
Low Cost ◽  
Practical Importance ◽  
Production Method ◽  
Raman Imaging ◽  
Textured Ceramics ◽  
The Matrix

ABSTRACTPMN(PZN)-PT single crystals exhibit unique electromechanical properties when oriented and poled along the <001> direction. While expensive crystal growth techniques are advancing slowly, it is of great practical importance to develop an alternative low-cost production method based on strongly oriented or textured ceramics. We present here the thermal expansion, dielectric properties and Raman spectroscopy study of Pb(Mg1/3Nb2/3)O3-PbTiO3 solid solution ((1-x)PMN-xPT, 0.2<x <0.4, here after called PMN xPT) single crystals, random ceramics and ceramics prepared by homo-templated grain growth (HTGG) using cubic PMN-PT single crystal seeds as templates and nanoparticles as ceramic matrix. Representative medium to highly textured ceramics were sintered at 1150°C and 1200°C, respectively, and studied by Raman imaging. Raman peak centre of gravity is used to image the x-composition whereas peak intensity is correlated to the unit-cell distortion and related short-range structure. Smart Raman imaging shows that the final composition is very close to that of the matrix. We compare their thermal expansion (-150 to 300°C) and dielectric properties (R.T. to 300°C) with those of corresponding poled or non-poled single crystals and random ceramics homologues. Short-range ordering and phase diagram are discussed.

Crystal structure, thermal expansion and dielectric properties of monoclinic ethylenediammonium bis(hydrogensuccinate), H3N(CH2)2NH3(HC4H4O4)2

1994 ◽  
Vol 209 (1) ◽  
Author(s):  
J. Schreuer ◽  
T. Münch
Keyword(s):  
Crystal Structure ◽  
Thermal Expansion ◽  
Dielectric Properties ◽  
Aqueous Solutions ◽  
Single Crystals ◽  
Structure Analysis ◽  
Optical Quality ◽  
Space Group ◽  
X Ray

AbstractLarge single crystals of optical quality of monoclinic ethylenediammonium bis(hydrogensuccinate) were grown from aqueous solutions. An X-ray structure analysis yielded space group

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

STRUCTURAL TRANSFORMATION STUDIED BY THERMAL EXPANSION ON SINGLE CRYSTALS V3Si IN NORMAL AND SUPERCONDUCTING STATES

1978 ◽  
Vol 39 (C6) ◽  
pp. C6-406-C6-407 ◽  
Author(s):  
T. Fukase ◽  
T. Kobayashi ◽  
M. Isino ◽  
N. Toyota ◽  
Y. Muto
Keyword(s):  
Thermal Expansion ◽  
Single Crystals ◽  
Structural Transformation

scholarly journals Fabrication and Characterization of the Modified EV31-Based Metal Matrix Nanocomposites

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 125
Author(s):  
Seyed Kiomars Moheimani ◽  
Mehran Dadkhah ◽  
Mohammad Hossein Mosallanejad ◽  
Abdollah Saboori
Keyword(s):  
Thermal Expansion ◽  
Mechanical Strength ◽  
Metal Matrix ◽  
Coefficient Of Thermal Expansion ◽  
Structural Effect ◽  
Metal Matrix Nanocomposites ◽  
Mechanical Stirring ◽  
Specific Strength ◽  
The Matrix ◽  
Matrix Nanocomposites

Metal matrix nanocomposites (MMNCs) with high specific strength have been of interest for numerous researchers. In the current study, Mg matrix nanocomposites reinforced with AlN nanoparticles were produced using the mechanical stirring-assisted casting method. Microstructure, hardness, physical, thermal and electrical properties of the produced composites were characterized in this work. According to the microstructural evaluations, the ceramic nanoparticles were uniformly dispersed within the matrix by applying a mechanical stirring. At higher AlN contents, however, some agglomerates were observed as a consequence of a particle-pushing mechanism during the solidification. Microhardness results showed a slight improvement in the mechanical strength of the nanocomposites following the addition of AlN nanoparticles. Interestingly, nanocomposite samples were featured with higher electrical and thermal conductivities, which can be attributed to the structural effect of nanoparticles within the matrix. Moreover, thermal expansion analysis of the nanocomposites indicated that the presence of nanoparticles lowered the Coefficient of Thermal Expansion (CTE) in the case of nanocomposites. All in all, this combination of properties, including high mechanical strength, thermal and electrical conductivity, together with low CTE, make these new nanocomposites very promising materials for electro packaging applications.

scholarly journals Comparison of the Dielectric Properties of Ecoflex® with L,D-Poly(Lactic Acid) or Polycaprolactone in the Presence of SWCN or 5CB

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1719
Author(s):  
Patryk Fryń ◽  
Sebastian Lalik ◽  
Natalia Górska ◽  
Agnieszka Iwan ◽  
Monika Marzec
Keyword(s):  
Oleic Acid ◽  
Dielectric Properties ◽  
Polymer Matrix ◽  
Liquid Crystalline ◽  
Weight Ratio ◽  
Poly Lactic Acid ◽  
Relaxation Processes ◽  
The Matrix ◽  
Walled Carbon Nanotubes ◽  
Hybrid Layers

The main goal of this paper was to study the dielectric properties of hybrid binary and ternary composites based on biodegradable polymer Ecoflex®, single walled carbon nanotubes (SWCN), and liquid crystalline 4′-pentyl-4-biphenylcarbonitrile (5CB) compound. The obtained results were compared with other created analogically to Ecoflex®, hybrid layers based on biodegradable polymers such as L,D-polylactide (L,D-PLA) and polycaprolactone (PCL). Frequency domain dielectric spectroscopy (FDDS) results were analyzed taking into consideration the amount of SWCN, frequency, and temperature. For pure Ecoflex®, two relaxation processes (α and β) were identified. It was shown that the SWCN admixture (in the weight ratio 10:0.01) did not change the properties of the Ecoflex® layer, while in the case of PCL and L,D-PLA, the layers became conductive. The dielectric constant increased with an increase in the content of SWCN in the Ecoflex® matrix and the conductive behavior was not visible, even for the greatest concentration (10:0.06 weight ratio). In the case of the Ecoflex® polymer matrix, the conduction relaxation process at a frequency ca. several kilohertz appeared and became stronger with an increase in the SWCN admixture in the matrix. Addition of oleic acid to the polymer matrix had a smaller effect on the increase in the dielectric response than the addition of liquid crystal 5CB. Fourier transform infrared (FTIR) results revealed that the molecular structure and chemical character of the Ecoflex® and PCL matrixes remained unchanged upon the addition of SWCN or 5CB in a weight ratio of 10:0.01 and 10:1, respectively, while molecular interactions appeared between L,D-PLA and 5CB. Moreover, adding oleic acid to pure Ecoflex® as well as the binary and ternary hybrid layers with SWCN and/or 5CB in a weight ratio of Ecoflex®:oleic acid equal to 10:0.3 did not have an influence on the chemical bonding of these materials.

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