Extreme Room Temperature Compression and Bending in Ferroelectric Oxide Pillars

2021 ◽  
Author(s):  
Ying Liu ◽  
Xiangyuan Cui ◽  
Ranming Niu ◽  
Shujun Zhang ◽  
Xiaozhou Liao ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Ceramic Materials ◽  
Perovskite Oxide ◽  
High Concentration ◽  
Bending Tests ◽  
Ionic Bonds ◽  
Order Of Magnitude ◽  
Mn Doped

Abstract Plastic deformation in ceramic materials is normally only observed in nanometre-sized samples. However, we have observed unprecedented levels of plasticity (>50% plastic strain) and excellent elasticity (6% elastic strain) in perovskite oxide Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT), under compression along <100>pc pillars up to 2.1 μm in diameter. The extent of this deformation is much higher than has previously been reported for ceramic materials, and the sample size at which plasticity is observed is almost an order of magnitude larger. Bending tests also revealed over 8% flexural strain. Plastic deformation occurred by slip along {110} <110>. Calculations indicate that the resulting strain gradients will give rise to extreme flexoelectric polarization. First principles models predict that a high concentration of oxygen vacancies (Vo) weaken the covalent/ionic bonds, giving rise to the unexpected plasticity. Mechanical testing on Vo-rich Mn-doped PIN-PMN-PT confirmed this prediction. These findings will facilitate the design of plastic ceramic materials and the development of flexoelectric-based nano-electromechanical systems.

scholarly journals Nanoscale stacking fault–assisted room temperature plasticity in flash-sintered TiO2

2019 ◽  
Vol 5 (9) ◽  
pp. eaaw5519 ◽  
Author(s):  
Jin Li ◽  
Jaehun Cho ◽  
Jie Ding ◽  
Harry Charalambous ◽  
Sichuang Xue ◽  
...  
Keyword(s):  
Room Temperature ◽  
Oxygen Vacancies ◽  
Crack Formation ◽  
High Stress ◽  
Ceramic Materials ◽  
Sintering Process ◽  
Flash Sintering ◽  
Structural Applications ◽  
Deformation Behaviors

Ceramic materials have been widely used for structural applications. However, most ceramics have rather limited plasticity at low temperatures and fracture well before the onset of plastic yielding. The brittle nature of ceramics arises from the lack of dislocation activity and the need for high stress to nucleate dislocations. Here, we have investigated the deformability of TiO2 prepared by a flash-sintering technique. Our in situ studies show that the flash-sintered TiO2 can be compressed to ~10% strain under room temperature without noticeable crack formation. The room temperature plasticity in flash-sintered TiO2 is attributed to the formation of nanoscale stacking faults and nanotwins, which may be assisted by the high-density preexisting defects and oxygen vacancies introduced by the flash-sintering process. Distinct deformation behaviors have been observed in flash-sintered TiO2 deformed at different testing temperatures, ranging from room temperature to 600°C. Potential mechanisms that may render ductile ceramic materials are discussed.

On the “Ceramic Constrained by Metal” Composite Materials

2013 ◽  
Vol 833 ◽  
pp. 266-270
Author(s):  
Chuan Sun ◽  
Yun Kai Li ◽  
Hu Wang ◽  
Ming Ming Wan ◽  
Yun Fei Wang ◽  
...  
Keyword(s):  
Brittle Failure ◽  
Room Temperature ◽  
Bending Strength ◽  
Ceramic Materials ◽  
Metal Composite ◽  
Bending Tests ◽  
Lateral Confinement ◽  
Application Range ◽  
Three Point Bending ◽  
Metal Composite Materials

Ceramics are widely used in every field of contemporary industrial because of its many excellent properties. However, its mechanical property is great brittleness and small toughness for the characteristics of internal chemical bond, which restricts its application range to a large extent. Therefore, how to improve mechanical properties of ceramic materials has been attracted a great attention in the relevant area. For ceramics using at room temperature, a method which can avoid brittle failure by metal confinement outside of ceramics is given. And the feasibility of this method is discussed. Three point bending tests were conduct on ZrO2 ceramics with and without lateral confinement separately. Base on the much of experimental conclusion, the bending strength of ceramic with lateral confinement was improved largely.

Ultrasound-assisted synthesis of a feathery-shaped BiOCl with abundant oxygen vacancies and efficient visible-light photoactivity

2018 ◽  
Vol 42 (24) ◽  
pp. 19571-19577 ◽  
Author(s):  
Jingyu Sun ◽  
Haiming Xu ◽  
Dongya Li ◽  
Zhongwei Zou ◽  
Qiyuan Wu ◽  
...  
Keyword(s):  
Visible Light ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
High Concentration ◽  
Ultrasound Method ◽  
Ultrasound Assisted

A feathery-shaped form of BiOCl (BOC-M) with a high concentration of oxygen vacancies was successfully synthesized using the ultrasound method at room temperature with maltitol as a surfactant.

Room-Temperature Ferromagnetism in Mn-Doped CuCrO2 Nanopowders

2019 ◽  
Vol 971 ◽  
pp. 91-100
Author(s):  
Jing Jing Ji ◽  
Fang Ting Lin ◽  
Xiao Yong He ◽  
Hui Shi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Double Exchange ◽  
Hole Density ◽  
Double Exchange Interaction ◽  
Order Of Magnitude ◽  
Microstructure Morphology ◽  
A Site ◽  
Mn Doped

(Cu1-xMnx)CrO2 (0≤ x ≤6 at%) and Cu (Cr1-yMny)O2 (0≤ y ≤6 at%) nanopowders were prepared by combining solid-state reaction and ball milling. The Mn concentration dependences of microstructure, morphology and magnetic properties were investigated. It is found that all the samples have a pure 3R-CuCrO2 delafossite structure. The lattice expansion supports the Mn entrance into the Cu and Cr sublattices, respectively, in (Cu1-xMnx)CrO2 and Cu (Cr1-yMny)O2, which is further proved by X-ray photoelectron spectroscopy to some degree. A-site Mn substitution brings about paramagnetic behavior. However, room-temperature ferromagnetism is achieved in B-site Mn-doped samples, originating from the hole-mediated Cr3+–Mn3+ double-exchange interaction. The saturation magnetization of this CuMO2 delafossite (M=Cr, Mn) is about an order of magnitude higher than literature values, and gradually decreased with the Mn addition due to the combined influence of the number of the M–M pairs, the M–M distances and the hole density.

Oxidation Resistance and Bending Strength at High Temperatures of Ni/(ZrO2+Al2O3) Hybrid Materials

2018 ◽  
Vol 922 ◽  
pp. 104-109
Author(s):  
Hai Vu Pham ◽  
Makoto Nanko ◽  
Wataru Nakao
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Cross Section ◽  
High Temperatures ◽  
Room Temperature ◽  
Bending Strength ◽  
Bending Tests ◽  
Three Point Bending ◽  
Order Of Magnitude ◽  
Zone Development

Oxidation resistance and bending strength at high temperatures of 5 vol% Ni/(10 vol% ZrO2+Al2O3) were investigated in this paper. Oxidation tests were conducted at temperature ranging from 1100 to 1300oC for 1 to 24 h in air. The oxidation resistance of the composites was studied via observation of oxidized-zone development from a cross-section view after oxidation. Three-point bending tests were conducted at temperatures ranging from room temperature to 1200oC in order to estimate its performance at high temperatures. Bending strength of the composites achieved 1200 MPa at room temperature and 460 MPa at 1200oC. Dispersion of ZrO2in Ni/Al2O3composites enhanced both their room and high temperature bending strength. Nevertheless, ZrO2slightly degraded the oxidation resistance of the composites. The oxidation rate of Ni/(ZrO2+Al2O3) was one order of magnitude higher than that of Ni/Al2O3.

Defects and charge transport in Mn-doped K0.5Na0.5NbO3 ceramics

2015 ◽  
Vol 17 (37) ◽  
pp. 24403-24411 ◽  
Author(s):  
Muhammad Asif Rafiq ◽  
Alexander Tkach ◽  
Maria Elisabete Costa ◽  
Paula Maria Vilarinho
Keyword(s):  
Charge Transport ◽  
Hysteresis Loop ◽  
Grain Boundaries ◽  
High Temperatures ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Hole Transport ◽  
Mn Doping ◽  
Mn Doped ◽  
Temperature Conduction

KNN room-temperature conduction is associated with hole transport and can be suppressed by Mn-doping; a less leaky hysteresis loop is obtained. At high temperatures conduction is dominated by ionized oxygen vacancies motion. From grains and grain-boundaries resistance oxygen vacancies in KNN and Mn-doped KNN ceramics are mainly located at grain-boundaries.

Structural and Optical Investigation of Mn-Doped ZnS Nanocrystals

2005 ◽  
Vol 475-479 ◽  
pp. 1795-1798 ◽  
Author(s):  
W.Q. Peng ◽  
S.C. Qu ◽  
G.W. Cong ◽  
Z.G. Wang
Keyword(s):  
Visible Spectrum ◽  
Optical Investigation ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Zinc Blende ◽  
Order Of Magnitude ◽  
Zns Nanocrystals ◽  
Average Size ◽  
Mn Doped ◽  
Zinc Blende Structure

Using a solution-based chemical method, we have prepared ZnS nanocrystals doped with high concentration of Mn2+. The X-ray diffraction analysis confirmed a zinc blende structure. The average size was about 3 nm. Photoluminescence spectrum showed room temperature emission in the visible spectrum, which consisted of the defect-related emission and the 4 T1-6 A1 emission of Mn2+ ions. Compared with the undoped sample, the luminescence of the ZnS:Mn sample is enhanced by more than an order of magnitude, which indicated that the Mn2+ ions can efficiently boost the luminescence of ZnS nanocrystals.

An insight into the origin of room-temperature ferromagnetism in SnO2 and Mn-doped SnO2 quantum dots: an experimental and DFT approach

2018 ◽  
Vol 20 (9) ◽  
pp. 6500-6514 ◽  
Author(s):  
Dhamodaran Manikandan ◽  
D. W. Boukhvalov ◽  
S. Amirthapandian ◽  
I. S. Zhidkov ◽  
A. I. Kukharenko ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Room Temperature Ferromagnetism ◽  
Mn Doped ◽  
Insight Into ◽  
Multiple Configurations

Oxygen vacancies and multiple configurations of Mn (Mn2+ and Mn3+) might be the cause of the observed room-temperature ferromagnetism in SnO2 QDs.

scholarly journals Electroplating of Pure Aluminum from [HMIm][TFSI]–AlCl3 Room-Temperature Ionic Liquid

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1414
Author(s):  
Yarden Melamed ◽  
Nabasmita Maity ◽  
Louisa Meshi ◽  
Noam Eliaz
Keyword(s):  
Ionic Liquid ◽  
Deposition Rate ◽  
Room Temperature ◽  
Pure Aluminum ◽  
Nanocrystalline Structure ◽  
High Concentration ◽  
Good Surface ◽  
Industrial Sectors ◽  
Industrial Coating ◽  
Order Of Magnitude

Electrodeposition of aluminum and its alloys is of great interest in the aerospace, automobile, microelectronics, energy, recycle, and other industrial sectors, as well as for defense and, potentially, electrochemical printing applications. Here, for the first time, we report room-temperature electroplating of pure aluminum on copper and nickel substrates from an ionic liquid (IL) consisting of 1-Hexyl-3-methylimidazolium (HMIm) cation and bis(trifluoromethylsulfonyl)imide (TFSI) anion, with a high concentration of 8 mol/L AlCl3 aluminum precursor. The aluminum deposits are shown to have a homogeneous and dense nanocrystalline structure. A quasi-reversible reaction is monitored, where the current is affected by both charge transfer and mass transport. The electrocrystallization of Al on Ni is characterized by instantaneous nucleation. The deposited Al layers are dense, homogeneous, and of good surface coverage. They have a nanocrystalline, single-phase Al (FCC) structure, with a dislocation density typical of Al metal. An increase in the applied cathodic potential from −1.3 to −1.5 V vs. Pt resulted in more than one order of magnitude increase in the deposition rate (to ca. 44 μm per hour), as well as in ca. one order of magnitude finer grain size. The deposition rate is in accordance with typical industrial coating systems.

Effect of Nb and Mn Substitution on Bi0.5Na0.5TiO3 Lead-Free Piezoceramics with Enhanced Electrical Properties

2017 ◽  
Vol 863 ◽  
pp. 8-14
Author(s):  
Yu Chen Guo ◽  
Hui Qing Fan ◽  
Jing Shi
Keyword(s):  
Room Temperature ◽  
Ferroelectric Properties ◽  
Solid State Reaction Method ◽  
Perovskite Oxide ◽  
Lead Free ◽  
Conventional Solid State Reaction ◽  
Large Defect ◽  
Defect Dipole ◽  
Mn Doped

The perovskite oxide Bi0.5Na0.5MnxTi1-xO3, Bi0.5Na0.5NbxTi1-xO3, Bi0.5Na0.5 (Mn0.5Nb0.5)xTi1-xO3 and Bi0.5Na0.5TiO3 ceramics (x=0.25%) were prepared via the conventional solid state reaction method. The role of Mn as an acceptor, Nb as a donor and (Mn0.5Nb0.5) substitution at B site in BNT lead-free piezoceramics was investigated. The (Mn0.5Nb0.5) substitution led to the inhibited of reduction of Ti4+ to Ti3+ and gave rise to large defect-dipole clusters containing highly localized electrons which should be responsible for the increase of Tc and Td. The ferroelectric properties and field-induced strains were both improved by Mn-acceptor and (Mn0.5Nb0.5) co-doped. The fatigue-resistant properties of Nb doped BNT ceramics were comparable to BNT ceramics, Mn doped ceramics were found to have significantly improved fatigue-resistant properties, while almost no profound fatigue was observed in BNT-MnNb ceramics after switching over 106 cycles at room temperature.

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