scholarly journals Strengthening of Nanocrystalline Al with Al3Zr Core-Shell Structure

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1144
Author(s):  
Dora Janovszky
Keyword(s):  
Mechanical Properties ◽  
Shell Structure ◽  
Hot Pressing ◽  
Room Temperature ◽  
High Energy ◽  
Core Shell ◽  
Mixed Powder ◽  
Reinforcing Particles ◽  
Core Shell Structure ◽  
Nanocrystalline Phases

High-density Al-based composites reinforced with ten-wt.% recycled nanocrystalline CuZrAgAl particles have been fabricated by mechanical milling, cold- and hot-pressing. The microstructures, phase transformations, and mechanical properties of the mixed powder and sintered samples were investigated. After milling in a ball mill for 30 h, the microhardness of the mixed powder increases to 301 ± 31 HV0.01 and 222 ± 10 HV0.01 without and with ethanol milling, respectively. On account of the interdiffusion, the melting temperature of mixed powder reduces to 574 ± 5.0 °C and 627.5 ± 6.5 °C after 30 h milling. The study showed that the reinforcing particles are homogeneously distributed in the sintered nanocrystalline Al-based composites. During the hot-pressing, a shell zone forms at the interface of reinforcing particles during hot pressing after high energy milling with a minimum of ten hours milling time. This shell zone consists of Al3Zr (D023) phase. The coarsening resistant core-shell structure and grain refinement greatly improve mechanical properties. The compression strength at room temperature varies between 650 and 800 MPa at room temperature and is 380 MPa at 400 °C for the composite containing ten-wt.% of the Cu-Zr-based amorphous-nanocrystalline phases. The Brinell hardness of the sintered composite is 329 HB.

scholarly journals Rational synthesis of silicon into polyimide-derived hollow electrospun carbon nanofibers for enhanced lithium storage

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 491-499 ◽  
Author(s):  
Fan Wang ◽  
Shouzhi Zhang ◽  
Jiawei Zhang ◽  
Manshu Han ◽  
Guoxiang Pan ◽  
...  
Keyword(s):  
Shell Structure ◽  
Carbon Nanofiber ◽  
Lithium Ion ◽  
High Energy ◽  
High Energy Density ◽  
Superior Performance ◽  
Core Shell ◽  
Discharge Process ◽  
Energy Devices ◽  
Core Shell Structure

AbstractFlexible energy devices with high energy density and long cycle life are considered to be promising applications in portable electronics. In this study, silicon/carbon nanofiber (Si@CNF) core–shell electrode has been prepared by the coaxial electrospinning method. The precursors of polyimide (PI) were for the first time used to form the core–shell structure of Si@CNF, which depicts outstanding flexibility and mechanical strength. The effect of doping concentrations of silicon (Si) nanoparticles embedded in the fiber is investigated as a binder-free anode for lithium-ion batteries. A 15 wt% doped composite electrode demonstrates superior performance, with an initial reversible capacity of 621 mA h g−1 at the current density of 100 mA g−1 and a high capacity retention up to 200 cycles. The excellent cycling performance is mainly due to the carbonized PI core–shell structure, which not only can compensate for the insulation property of Si but also has the ability to buffer the volume expansion during the repeated charge–discharge process.

Design of PP/EPDM/NBR TPVs with tunable mechanical properties via regulating the core-shell structure

2020 ◽  
Vol 90 ◽  
pp. 106767
Author(s):  
Tao Peng ◽  
Fei Lv ◽  
Zhou Gong ◽  
Liming Cao ◽  
Xuesong Yan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shell Structure ◽  
Core Shell ◽  
The Core ◽  
Core Shell Structure ◽  
Tunable Mechanical Properties

A core–shell structure of cobalt sulfide//G-ink towards high energy density in asymmetric hybrid supercapacitors

2020 ◽  
Vol 4 (9) ◽  
pp. 4848-4858
Author(s):  
Venkata Thulasivarma Chebrolu ◽  
Balamuralitharan Balakrishnan ◽  
Aravindha Raja Selvaraj ◽  
Hee-Je Kim
Keyword(s):  
Energy Density ◽  
Shell Structure ◽  
High Energy ◽  
High Energy Density ◽  
Cobalt Sulfide ◽  
Core Shell ◽  
Hybrid Supercapacitors ◽  
Promising Strategy ◽  
Asymmetric Hybrid ◽  
Core Shell Structure

New atom substitution in transition metals is a promising strategy for improving the performance of supercapacitors (SCs).

A mesoporous Ni3N/NiO composite with a core–shell structure for room temperature, selective and sensitive NO2 gas sensing

RSC Advances ◽  
2016 ◽  
Vol 6 (49) ◽  
pp. 42917-42922 ◽  
Author(s):  
Mingming Zou ◽  
Hu Meng ◽  
Fengdong Qu ◽  
Liang Feng ◽  
Minghui Yang
Keyword(s):  
Shell Structure ◽  
Room Temperature ◽  
Gas Sensing ◽  
Core Shell ◽  
Template Free ◽  
Core Shell Structure

Mesoporous Ni3N/NiO composites with core–shell structure were synthesized by a template free method, demonstrate a significant improvements both in sensitivity and in selectivity for NO2 gas sensing at room temperature.

Au@ZnO core–shell structure for gaseous formaldehyde sensing at room temperature

2014 ◽  
Vol 199 ◽  
pp. 314-319 ◽  
Author(s):  
Feng-Chao Chung ◽  
Zhen Zhu ◽  
Peng-Yi Luo ◽  
Ren-Jang Wu ◽  
Wei Li
Keyword(s):  
Shell Structure ◽  
Room Temperature ◽  
Core Shell ◽  
Formaldehyde Sensing ◽  
Core Shell Structure ◽  
Gaseous Formaldehyde

A BIO-INSPIRED POLYDOPAMINE APPROACH TO PREPARATION OF GOLD-COATED Fe3O4 CORE–SHELL NANOPARTICLES: SYNTHESIS, CHARACTERIZATION AND MECHANISM

NANO ◽  
2013 ◽  
Vol 08 (06) ◽  
pp. 1350061 ◽  
Author(s):  
PENG AN ◽  
FANG ZUO ◽  
XINHUA LI ◽  
YUANPENG WU ◽  
JUNHUA ZHANG ◽  
...  
Keyword(s):  
Shell Structure ◽  
Room Temperature ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Stabilizing Agent ◽  
X Ray ◽  
Transmission Electron ◽  
Core Shell Structure ◽  
Core Shell Nanoparticles

A biomimetic and facile approach for integrating Fe 3 O 4 and Au with polydopamine (PDA) was proposed to construct gold-coated Fe 3 O 4 nanoparticles ( Fe 3 O 4@ Au – PDA ) with a core–shell structure by coupling in situ reduction with a seed-mediated method in aqueous solution at room temperature. The morphology, structure and composition of the core–shell structured Fe 3 O 4@ Au – PDA nanoparticles were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectrometry (XPS). The formation process of Au shell was assessed using a UV-Vis spectrophotometer. More importantly, according to investigating changes in PDA molecules by Fourier transform infrared spectroscopy (FTIR) and in preparation process of the zeta-potential data of nanoparticles, the mechanism of core–shell structure formation was proposed. Firstly, PDA-coated Fe 3 O 4 are obtained using dopamine (DA) self-polymerization to form thin and surface-adherent PDA films onto the surface of a Fe 3 O 4 "core". Then, Au seeds are attached on the surface of PDA-coated Fe 3 O 4 via electrostatic interaction in order to serve as nucleation centers catalyzing the reduction of Au 3+ to Au 0 by the catechol groups in PDA. Accompanied by the deposition of Au , PDA films transfer from the surface of Fe 3 O 4 to that of Au as stabilizing agent. In order to confirm the reasonableness of this mechanism, two verification experiments were conducted. The presence of PDA on the surface of Fe 3 O 4@ Au – PDA nanoparticles was confirmed by the finding that glycine or ethylenediamine could be grafted onto Fe 3 O 4@ Au – PDA nanoparticles through Schiff base reaction. In addition, Fe 3 O 4@ Au – DA nanoparticles, in which DA was substituted for PDA, were prepared using the same method as that for Fe 3 O 4@ Au – PDA nanoparticles and characterized by UV-Vis, TEM and FTIR. The results validated that DA possesses multiple functions of attaching Au seeds as well as acting as both reductant and stabilizing agent, the same functions as those of PDA.

scholarly journals Preparation of CaCO3-SiO2 composite with core-shell structure and its application in silicone rubber

2015 ◽  
Vol 17 (4) ◽  
pp. 128-133 ◽  
Author(s):  
Chenglin Cui ◽  
Hao Ding ◽  
Li Cao ◽  
Daimei Chen
Keyword(s):  
Mechanical Properties ◽  
Silicone Rubber ◽  
Shell Structure ◽  
Breaking Strength ◽  
Core Shell ◽  
Elongation At Break ◽  
Chemistry Method ◽  
Core Shell Structure

Abstract A new CaCO3-SiO2 composite with core-shell structure was successfully prepared by mechano-chemistry method (MCM). SEM and FTIR indicated that SiO2 particles were homogeneously immobilized on the surface of CaCO3. The well dispersion of this CaCO3-SiO2 composite into silicone rubber can not only reduce the usage amount of SiO2, but also improve the mechanical properties of silicone rubber. By the calculation, the theoretical numbers of the SiO2 particles is about 10 times as large as that of CaCO3 particles in the CaCO3-SiO2 composite. Mixing CaCO3-SiO2 composite in silicone rubber can enhance the breaking strength of the silicone rubber about 18% as high as that when mixing the pure SiO2. And the elongation at break is about 14% less than that of adding the pure SiO2 sample.

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