scholarly journals Microstructure and Electrical Property of Ex-Situ and In-Situ Copper Titanium Carbide Nanocomposites

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 735
Author(s):  
Nguyen Hoang Viet ◽  
Nguyen Thi Hoang Oanh

In this study, ex-situ Cu-TiC nanocomposites of 1, 3 and 5 vol. % TiC and in-situ Cu-TiH2-C nanocomposites (corresponding to 5 vol. % TiC) were prepared using ball milling and spark plasma sintering methods. Powder mixtures were milled for 4 h at 400 rpm. As-milled Cu-TiC composite powders were consolidated under an applied pressure of 70 MPa. The phase composition, and microstructure of the composite samples were characterized by X-ray diffraction, and scanning electron microscope and transmission electron microscope techniques, respectively. With the increasing TiC content from 1 to 5 vol. %, the hardness of the ex-situ composites when sintered at 600 °C changed between 161.4 and 178.5 HV and the electrical conductivity decreased from 52.1 to 47.6% IACS. In-situ Cu-TiH2-C nanocomposite sintered at 950 °C had higher hardness and electrical conductivity than ex-situ Cu-TiC composite due to having a homogenous distribution of nano reinforcement particles and dense structure.

2021 ◽  
Vol 10 (3) ◽  
pp. 578-586
Author(s):  
Lin-Kun Shi ◽  
Xiaobing Zhou ◽  
Jian-Qing Dai ◽  
Ke Chen ◽  
Zhengren Huang ◽  
...  

AbstractA nano-laminated Y3Si2C2 ceramic material was successfully synthesized via an in situ reaction between YH2 and SiC using spark plasma sintering technology. A MAX phase-like ternary layered structure of Y3Si2C2 was observed at the atomic-scale by high resolution transmission electron microscopy. The lattice parameters calculated from both X-ray diffraction and selected area electron diffraction patterns are in good agreement with the reported theoretical results. The nano-laminated fracture of kink boundaries, delamination, and slipping were observed at the tip of the Vickers indents. The elastic modulus and Vickers hardness of Y3Si2C2 ceramics (with 5.5 wt% Y2O3) sintered at 1500 °C were 156 and 6.4 GPa, respectively. The corresponding values of thermal and electrical conductivity were 13.7 W·m-1·K-1 and 6.3×105 S·m-1, respectively.


2020 ◽  
Author(s):  
Lin-Kun Shi ◽  
Xiaobing Zhou ◽  
Jian-Qing Dai ◽  
Ke Chen ◽  
Zhengren Huang ◽  
...  

Abstract A new nano-laminated Y3Si2C2 ceramic material, for the first time, was successfully synthesized via in situ reaction between YH2 and SiC by spark plasma sintering. A MAX phase-like ternary layered structure of Y3Si2C2 was observed at the atomic-scale by high resolution transmission electron microscopy. The lattice parameters calculated from both X-ray diffraction and selected area electron diffraction patterns are in good agreement with the reported theoretical results. The nano-laminated fracture of kink boundaries, delamination, and slipping was observed at the tip of the Vickers indent. The values of elastic modulus and Vickers hardness of the Y3Si2C2 ceramics sintered at 1500 °C were 156 and 6.4 GPa, respectively. The corresponding values of thermal and electrical conductivity were 13.7 W m-1 k-1 and 6.3 × 105 S m-1, respectively.


2013 ◽  
Vol 745-746 ◽  
pp. 551-554 ◽  
Author(s):  
Ming Hui Wang ◽  
Hua Jian Li ◽  
Wan Jiang

TiB2/TiN nanocomposites were in-situ fabricated by spark plasma sintering (SPS) technique using Ti and BN powders as starting materials. The phase constituents and microstructures of the samples were analyzed by X-ray diffraction (XRD) techniques, scanning electron microscopy (SEM) and transmission electron microscope (TEM), respectively. The results showed that the average grain size of TiB2 and TiN was 1m and 300nm respectively. Furthermore, high resolution TEM analysis indicated that the as-prepared TiB2/TiN nanocomposites had very clean grain boundaries, and no amorphous phase or oxide layer was observed.


2017 ◽  
Vol 19 (31) ◽  
pp. 20867-20880 ◽  
Author(s):  
David C. Bock ◽  
Christopher J. Pelliccione ◽  
Wei Zhang ◽  
Janis Timoshenko ◽  
K. W. Knehr ◽  
...  

Crystal and atomic structural changes of Fe3O4upon electrochemical (de)lithiation were determined.


2020 ◽  
Vol MA2020-02 (24) ◽  
pp. 1750-1750
Author(s):  
Andrea Quintero Colmenares ◽  
Patrice Gergaud ◽  
Jean-Michel Hartmann ◽  
Vincent Delaye ◽  
Nicolas Bernier ◽  
...  

2000 ◽  
Vol 650 ◽  
Author(s):  
A. Meldrum ◽  
K. Beaty ◽  
L. A. Boatner ◽  
C. W. White

ABSTRACTIrradiation-induced amorphization of Cd2Nb2O7 pyrochlore was investigated by means of in-situ temperature-dependent ion-irradiation experiments in a transmission electron microscope, combined with ex-situ ion-implantation (at ambient temperature) and RBS/channeling analysis. The in-situ experiments were performed using Ne or Xe ions with energies of 280 and 1200 keV, respectively. For the bulk implantation experiments, the incident ion energies were 70 keV (Ne+) and 320 keV (Xe2+). The critical amorphization temperature for Cd2Nb2O7 is ∼480 K (280 keV Ne+) or ∼620 K (1200 keV Xe2+). The dose for in-situ amorphization at room temperature is 0.22 dpa for Xe2+, but is 0.65 dpa for Ne+ irradiation. Both types of experiments suggest a cascade overlap mechanism of amorphization. The results were analyzed in light of available models for the crystalline-to-amorphous transformation and were compared to previous ionirradiation experiments on other pyrochlore compositions.


1993 ◽  
Vol 313 ◽  
Author(s):  
I. Hashim ◽  
H.A. Atwater ◽  
Thomas J. Watson

ABSTRACTWe have investigated structural and magnetic properties of epitaxial Ni80Fe20 films grown on relaxed epitaxial Cu/Si (001) films. The crystallographic texture of these films was analyzed in situ by reflection high energy electron diffraction (RHEED), and ex situ by x-ray diffraction and cross-sectional transmission electron Microscopy (XTEM). In particular, RHEED intensities were recorded during epitaxial growth, and intensity profiles across Bragg rods were used to calculate the surface lattice constant, and hence, find the critical epitaxial thickness for which Ni80Fe20 grows pseudomorphically on Cu (100). XTEM analysis indicated that the epitaxial films had atomically-abrupt interfaces which was not the case for polycrystalline Cu and Ni80Fe20 film interfaces. The Magnetic properties of these epitaxial films were Measured in situ using Magneto-optic Kerr effect magnetometry and were compared with those of polycrystalline films grown on SiO2/Si. Large Hc (∼ 35 Oe) was observed for epitaxial Ni80Fe20 films less than 3.0 nm thick whereas for increasing thickness, Hc decreased approximately monotonically to a few Oersteds. Correlations were made between magnetic properties of these epitaxial films, the strain in the film and the interface roughness obtained from XTEM analysis.


2002 ◽  
Vol 756 ◽  
Author(s):  
N. Pereira ◽  
M. Balasubramanian ◽  
L. Dupont ◽  
J. McBreen ◽  
L. C. Klein ◽  
...  

ABSTRACTGermanium nitride (Ge3N4) was examined as a potential negative electrode material for Li-ion batteries. The electrochemistry of Ge3N4 versus Li showed high reversible capacity (500mAh/g) and good capacity retention during cycling. A combination of ex-situ and in-situ x-ray diffraction (XRD), ex-situ transmission electron microscopy (TEM) and ex-situ selective area electron diffraction (SAED) analyses revealed evidence supporting the conversion of a layer of Ge3N4 crystal into an amorphous Li3N+LixGe nanocomposite during the first lithiation. The nanocomposite was electrochemically active via a reversible Li-Ge alloying reaction while a core of unreacted Ge3N4 crystal remained inactive. The lithium/metal nitride conversion reaction process was kinetically hindered resulting in limited capacity. Mechanical milling was found to improve the material capacity.


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