scholarly journals Co-extrusion of zirconia core-shell rods with controlled porosity in the core

2018 ◽  
Vol 12 (3) ◽  
pp. 230-239
Author(s):  
Jaroslav Kastyl ◽  
Vaclav Pouchly ◽  
Martin Trunec
Keyword(s):  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Core Shell ◽  
Rheological Analysis ◽  
Binder Removal ◽  
The Core ◽  
Porous Core ◽  
Controlled Porosity ◽  
Dense Shell ◽  
Shell Geometry

A method for manufacturing bi-layered zirconia rods of core-shell geometry with a porous core and a dense shell has been developed. Core-shell rods were successfully prepared by thermoplastic co-extrusion of assembled feed rods composed of core and shell zirconia feedstocks. Rheological analysis and adjustment of the feedstock viscosities enabled co-extrusion of regular core-shell rods of uniform shell thickness. Tapioca starch was used as a pore-forming agent in the core feedstock. Binder removal and high temperature treatment had to be modified in order to safely remove the starch particles. Sintering analysis revealed constrained sintering of porous cores in the core-shell rods due to the rigid dense shell, which resulted in an increased porosity in the core. Defect-free core-shell rods with a core porosity of up to 40% and different thicknesses of the dense shell were prepared.

Fabrication of Porous SiC Sheets with Controlled Porosity from Waste Clutch Boards

2009 ◽  
Vol 1220 ◽  
Author(s):  
Yuya Domi ◽  
Shiro Shimada
Keyword(s):  
Diatomaceous Earth ◽  
Pore Diameter ◽  
Automatic Transmission ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Carbon Powder ◽  
Excess Carbon ◽  
Phenol Resin ◽  
Controlled Porosity ◽  
Porous Sic

AbstractWhen clutch boards are fabricated as friction sheets in automatic transmission of motorcars, their useless fragments are disposed of. In this study, an effective reuse of their waste clutch boards will be proposed. Clutch boards are composed of diatomaceous earth, carbon powder/fiber and phenol resin. Excess carbon in carbonized clutch boards was reacted with SiO formed from Si and SiO2 at 1500 °C in Ar to produce porous SiC sheets (79% porosity). High temperature treatment at 1700-1900 °C in vacuum made it possible to control the pore size of SiC sheets, having a main pore diameter range of 10 to 20 μm.SiC sheets with porosity (79% to <60%) were also fabricated by heating carbonized/impregnated sheets with phenol resin in SiO gas at 1500 °C. SiC sheets obtained by the repeated cycle of impregnation/decomposition of resin heating at 1700 °C gave a tensile strength of 19 MPa.When Aluminum-tri-sec-butoxide (ASB) solution was impregnated into SiC sheets oxidized at 1000-1200 °C in air and heated at 1400-1500 °C in Ar, SiC-mullite composite sheets with porosity (77%) were produced.

scholarly journals Novel Organically Modified Core-Shell Clay for Epoxy Composites—“SOBM Filler 1”

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Nnamdi Chibuike Iheaturu ◽  
Innocent Chimezie Madufor
Keyword(s):  
Weight Percent ◽  
Temperature Treatment ◽  
Epoxy Composites ◽  
High Temperature Treatment ◽  
Core Shell ◽  
Drilling Mud ◽  
Modified Clay ◽  
Hydrophilic Nature ◽  
Organically Modified ◽  
Ft Ir

Preparation of a novel organically modified clay from spent oil base drilling mud (SOBM) that could serve as core-shell clay filler for polymers is herein reported. Due to the hydrophilic nature of clay, its compatibility with polymer matrix was made possible through modification of the surface of the core clay sample with 3-aminopropyltriethoxysilane (3-APTES) compound prior to its use. Fourier transform infrared (FT-IR) spectroscopy was used to characterize clay surface modification. Electron dispersive X-ray diffraction (EDX) and scanning electron microscopy (SEM) were used to expose filler chemical composition and morphology, while electrophoresis measurement was used to examine level of filler dispersion. Results show an agglomerated core clay powder after high temperature treatment, while EDX analysis shows that the organically modified clay is composed of chemical inhomogeneities, wherein elemental compositions in weight percent vary from one point to the other in a probe of two points. Micrographs of the 3-APTES coupled SOBM core-shell clay filler clearly show cloudy appearance, while FT-IR indicates 25% and 5% increases in fundamental vibrations band at 1014 cm−1 and 1435 cm−1, respectively. Furthermore, 3-APTES coupled core-shell clay was used to prepare epoxy composites and tested for mechanical properties.

Transformation of alumina-supported Pt-Au alloyed nanoparticles into core-shell Pt@Au structures during high-temperature treatment

2020 ◽  
Vol 22 (5) ◽  
Author(s):  
Aleksey A. Vedyagin ◽  
Yury V. Shubin ◽  
Pavel E. Plyusnin ◽  
Vladimir O. Stoyanovskii ◽  
Roman M. Kenzhin
Keyword(s):  
High Temperature ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Core Shell

scholarly journals A core–shell cathode substrate for developing high-loading, high-performance lithium–sulfur batteries

2018 ◽  
Vol 6 (48) ◽  
pp. 24841-24847 ◽  
Author(s):  
Ran Yu ◽  
Sheng-Heng Chung ◽  
Chun-Hua Chen ◽  
Arumugam Manthiram
Keyword(s):  
High Performance ◽  
Active Material ◽  
Three Dimensional ◽  
High Loading ◽  
Core Shell ◽  
Porous Core ◽  
Lithium Sulfur Batteries ◽  
Cathode Substrate ◽  
Dense Shell ◽  
Lithium Sulfur

The internal porous core and external dense shell of the three-dimensional cathode substrate, respectively, accommodate and encapsulate a large amount of active material.

Magnetic Properties of Fe3O4/CoFe2O4 Composite Nanoparticles with Core/Shell Architecture

2020 ◽  
Vol 65 (10) ◽  
pp. 904
Author(s):  
V. O. Zamorskyi ◽  
Ya. M. Lytvynenko ◽  
A. M. Pogorily ◽  
A. I. Tovstolytkin ◽  
S. O. Solopan ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Spinel Ferrite ◽  
Composite Nanoparticles ◽  
Core Shell ◽  
Cofe2o4 Nanoparticles ◽  
Core Diameter ◽  
The Core ◽  
Shell Particles ◽  
Interface Parameters ◽  
Shell Composite

Magnetic properties of the sets of Fe3O4(core)/CoFe2O4(shell) composite nanoparticles with a core diameter of about 6.3 nm and various shell thicknesses (0, 1.0, and 2.5 nm), as well as the mixtures of Fe3O4 and CoFe2O4 nanoparticles taken in the ratios corresponding to the core/shell material contents in the former case, have been studied. The results of magnetic research showed that the coating of magnetic nanoparticles with a shell gives rise to the appearance of two simultaneous effects: the modification of the core/shell interface parameters and the parameter change in both the nanoparticle’s core and shell themselves. As a result, the core/shell particles acquire new characteristics that are inherent neither to Fe3O4 nor to CoFe2O4. The obtained results open the way to the optimization and adaptation of the parameters of the core/shell spinel-ferrite-based nanoparticles for their application in various technological and biomedical domains.

Preparation of Porous Core/Shell Structure Fe$lt;inf$gt;2$lt;/inf$gt;O$lt;inf$gt;3$lt;/inf$gt;/Al Nanothermite Membrane by Template Method

2015 ◽  
Vol 30 (6) ◽  
pp. 610 ◽  
Author(s):  
ZHENG Guo-Qiang ◽  
ZHANG Wen-Chao ◽  
XU Xing ◽  
SHEN Rui-Qi ◽  
DENG Ji-Ping ◽  
...  
Keyword(s):  
Shell Structure ◽  
Template Method ◽  
Core Shell ◽  
Porous Core ◽  
Core Shell Structure
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