Enhanced fatigue resistance and lattice dynamics induced by the strong local strain in Fe-doped KTa1-xNbxO3 single crystal

2021 ◽  
Author(s):  
Xiaolin Huang ◽  
Peng Tan ◽  
Yu Wang ◽  
Yao Zhang ◽  
Xiangda Meng ◽  
...  
Keyword(s):  
Single Crystal ◽  
Fatigue Resistance ◽  
Lattice Dynamics ◽  
Piezoelectric Materials ◽  
Local Strain ◽  
Lead Free ◽  
Fatigue Properties ◽  
Practical Applications ◽  
Local Structures ◽  
The Impact

Improvement of durability is greatly important for the practical applications of lead-free-doped piezoelectric materials. However, the promotional mechanism of anti-fatigue properties and the impact on local structures from ion dopants...

The Characteristic of the La3Ga5SiO14 Single Crystal Grown by Vertical Bridgman Method in Ar Atmosphere

2006 ◽  
Vol 510-511 ◽  
pp. 842-845 ◽  
Author(s):  
Noriko Bamba ◽  
Kentaro Kato ◽  
Toshinori Taishi ◽  
Takayuki Hayashi ◽  
Keigo Hoshikawa ◽  
...  
Keyword(s):  
Melting Point ◽  
Single Crystal ◽  
Single Crystals ◽  
Room Temperature ◽  
Color Change ◽  
Piezoelectric Materials ◽  
Lead Free ◽  
Piezoelectric Constant ◽  
Interstitial Oxygen ◽  
Vertical Bridgman

Langasite (La3Ga5SiO14: denoted by LGS) single crystal is one of the lead free piezoelectric materials with high piezoelectricity that is maintained up to its melting point (1470°C). Although LGS single crystals have usually been grown by Czochralski (CZ) method in oxygen contained atmosphere to prevent evaporation of Ga, they were grown by the vertical Bridgman (VB) method in Ar atmosphere without oxygen, and their properties were evaluated in this work. Transparent and colorless LGS single crystals were successfully obtained without Ga evaporation by the VB method in Ar atmosphere, and their resistivity at room temperature was much higher than that grown by conventional CZ method. Piezoelectric constant d11 of the crystal grown by the VB method was 6 x 10-12 C/N, which was close to that of the crystal grown by CZ method. The colorless transparent LGS single crystal turned to orange and its resistivity decreased by annealing in air. Since an orange-colored transparent LGS single crystal has been grown by conventional CZ method, this indicates that color change and the resistivity decrease of LGS crystal is caused by extra interstitial oxygen atoms in the crystal.

scholarly journals Preparation and Characterization of Lead-Free Piezoelectric Ceramics

2011 ◽  
Vol 492 ◽  
pp. 189-193
Author(s):  
Qiang Chen ◽  
Jin Xu Li ◽  
Li Hui Zhang ◽  
Yang Bai ◽  
Yan Jing Su ◽  
...  
Keyword(s):  
Piezoelectric Coefficient ◽  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Piezoelectric Materials ◽  
Piezoelectric Ceramics ◽  
Lead Free ◽  
Practical Applications ◽  
Structure Density ◽  
Traditional Ceramics

(K,Na)NbO3-based piezoelectric ceramics are promising candidates for practical applications of lead-free piezoelectric materials due to their excellent piezoelectric properties. In this paper, lead-free piezoelectric ceramics (K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3(KNL-NTS)were successfully fabricated by traditional ceramics processing. The effects of sintering temperature on the structure, density and electrical properties of KNL-NTS ceramics were investigated. Crystal phases of both calcined powders and KNL-NTS ceramics have orthorhombic structure similar to that of KNbO3 ceramics. The piezoelectric coefficient first increases and then decreases with sintering temperature in the 1100-1180 °C range. KNL-NTS ceramics sintered at 1160 °C shows the maximum piezoelectric coefficient of about 199 pC·N-1and the maximum remnant polarization of 18.75 μC·cm-2, with the corresponding 10.95 kV·cm-1coercive field and 4.74 g/cm3density.

scholarly journals Anisotropy Factors and Electromechanical Coupling in Lead-Free 1–3-Type Composites

2019 ◽  
Author(s):  
Chris Bowen
Keyword(s):  
Single Crystal ◽  
Polymer Matrix ◽  
Electromechanical Coupling ◽  
Volume Fraction ◽  
Piezoelectric Materials ◽  
Lead Free ◽  
Aspect Ratios ◽  
Polymer Component ◽  
Coupling Factors

The effective electromechanical properties andanisotropy factors of novel lead-free 1–3-type compositesare studied to demonstrate their large piezoelectricanisotropy and considerable level of electromechanicalcoupling. The composites studied contain two single-crystal components and a polymer component. The firstpiezo-active component is a domain-engineered [001]-poled single crystal based on ferroelectric alkali niobates-tantalates, and this component is in the form of a system oflong rods that are parallel to the poling axis OX3. Thesecond single-crystal component is a system of spheroidalpiezoelectric Li2B4O7 inclusions aligned in a continuousand relatively large polymer matrix. The single-crystalrods are surrounded by a single crystal / polymer matrix,and the connectivity of the composite is 1–0–3. It is shownthat the conditions d * /| d * | 3 5, which indicates a large 33 31degree of anisotropy of the piezoelectric coefficients, and k* /|k* |35and k*/|k*|35,whichindicatealargeanisotropyof the electromechanical coupling factors, can be achievedsimultaneously in specific ranges of the component volumefractions and inclusion aspect ratios. Moreover, in thesame volume-fraction and aspect-ratio ranges, largeelectromechanical coupling factors (k* » k* » 0.8–0.9) are 33 talso achieved. In this context, the important role of the elastic properties of the continuous anisotropic matrix is discussed. The properties and anisotropy factors of the lead-free 1–3-type composites are compared to similar parameters of conventional lead-containing piezoelectric materials, and the advantages of the composite system studied are described.

scholarly journals Single Crystal Growth and Physical Properties of Pyroxene CoGeO3

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 378
Author(s):  
Li Zhao ◽  
Zhiwei Hu ◽  
Hanjie Guo ◽  
Christoph Geibel ◽  
Hong-Ji Lin ◽  
...  
Keyword(s):  
High Pressure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Crystal Growth ◽  
Physical Properties ◽  
Single Crystal ◽  
Single Crystals ◽  
Magnetic Moments ◽  
Single Crystal Growth ◽  
The Impact

We report on the synthesis and physical properties of cm-sized CoGeO3 single crystals grown in a high pressure mirror furnace at pressures of 80 bar. Direction dependent magnetic susceptibility measurements on our single crystals reveal highly anisotropic magnetic properties that we attribute to the impact of strong single ion anisotropy appearing in this system with TN∼33.5 K. Furthermore, we observe effective magnetic moments that are exceeding the spin only values of the Co ions, which reveals the presence of sizable orbital moments in CoGeO3.

scholarly journals Dark Self-Healing-Mediated Negative Photoconductivity of a Lead-Free Cs3Bi2Cl9 Perovskite Single Crystal

2021 ◽  
pp. 2286-2292
Author(s):  
Naveen Kumar Tailor ◽  
Partha Maity ◽  
Makhsud I. Saidaminov ◽  
Narayan Pradhan ◽  
Soumitra Satapathi
Keyword(s):  
Single Crystal ◽  
Lead Free ◽  
Self Healing ◽  
Negative Photoconductivity

Geometry Design and Contact Ratio Analysis for Circular Arc Parallel-Axis Helical Gears

2016 ◽  
Author(s):  
Z. Chen ◽  
B. Lei ◽  
Q. Zhao
Keyword(s):  
Rolling Process ◽  
Helical Gear ◽  
Space Curve ◽  
Impact Factors ◽  
Contact Ratio ◽  
Circular Arc ◽  
Practical Applications ◽  
Geometry Design ◽  
Gear Mechanism ◽  
The Impact

Based on space curve meshing theory, in this paper, we present a novel geometric design of a circular arc helical gear mechanism for parallel transmission with convex-concave circular arc profiles. The parameter equations describing the contact curves for both the driving gear and the driven gear were deduced from the space curve meshing equations, and parameter equations for calculating the convex-concave circular arc profiles were established both for internal meshing and external meshing. Furthermore, a formula for the contact ratio was deduced, and the impact factors influencing the contact ratio are discussed. Using the deduced equations, several numerical examples were considered to validate the contact ratio equation. The circular arc helical gear mechanism investigated in this study showed a high gear transmission performance when considering practical applications, such as a pure rolling process, a high contact ratio, and a large comprehensive strength.

Mechanical Properties of Equal-Channel Angular Extrusion-Processed Al-20Zn Alloy

2012 ◽  
Vol 445 ◽  
pp. 195-200
Author(s):  
Murat Aydin ◽  
Yakup Heyal
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Equal Channel Angular Extrusion ◽  
Considerable Change ◽  
Fatigue Properties ◽  
Dendritic Microstructure ◽  
Two Phase ◽  
Angular Extrusion ◽  
Alloy Increase ◽  
The Impact

The mechanical properties mainly tensile properties, impact toughness and high-cycle fatigue properties, of two-phase Al-20Zn alloy subjected to severe plastic deformation (SPD) via equal-channel angular extrusion (ECAE) using route A up to 2 passes were studied. The ECAE almost completely eliminated as-cast dendritic microstructure including casting defects such as micro porosities. A refined microstructure consisting of elongated micro constituents, α and α+η eutectic phases, formed after ECAE via route A. As a result of this microstructural change, mechanical properties mainly the impact toughness and fatigue performance of the as-cast Al-20Zn alloy increased significantly through the ECAE. The rates of increase in fatigue endurance limit are approximately 74 % after one pass and 89 % after two passes while the increase in impact toughness is 122 %. Also the yield and tensile strengths of the alloy increase with ECAE. However, no considerable change occurred in hardness and percentage elongation of the alloy. It was also observed that the ECAE changed the nature of the fatigue fracture characteristics of the as-cast Al-20Zn alloy.

Local strain evaluation of single crystal Si pillar by micro Raman spectroscopy and photoluminescence

2008 ◽  
Vol 517 (1) ◽  
pp. 31-33 ◽  
Author(s):  
Dong Wang ◽  
Hiroshi Nakashima ◽  
Masanori Tanaka ◽  
Taizoh Sadoh ◽  
Masanobu Miyao ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Single Crystal ◽  
Local Strain ◽  
Micro Raman Spectroscopy
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