scholarly journals Synthesis of biomorphaus SiC-ceramics

2007 ◽  
Vol 61 (2) ◽  
pp. 75-78
Author(s):  
Adela Egelja ◽  
Jelena Gulicovski ◽  
Aleksandar Devecerski ◽  
Snezana Boskovic ◽  
Branko Matovic
Keyword(s):  
Photoelectron Spectroscopy ◽  
Abies Alba ◽  
Microstructural Characterization ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Sic Ceramics ◽  
Silica Source ◽  
Porous Sic ◽  
Highly Porous

The carbothermal reduction processing of partially mineralized fir (Abies alba) samples was used to obtain highly-porous SiC ceramics with cellular structure. The infiltration of TEOS (tetraetilortosilikat, Si(OC2H5)4) as a silica source, was conducted in order to carry out the mineralization process. Synthesis of the SiC was achieved with a C/SiO2 replica annealing at 1723 K in Ar atmosphere. The obtained samples were characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The experimental results revealed that the hierarchical bimorphous wood structure was preserved even after high-temperature treatment. Microstructural characterization of the ceramics revealed the presence of the P-SiC phase and traces of the a-SiC phase.

Fabrication and characterization of cordierite-bonded porous SiC ceramics

2009 ◽  
Vol 35 (2) ◽  
pp. 597-602 ◽  
Author(s):  
Shifeng Liu ◽  
Yu-Ping Zeng ◽  
Dongliang Jiang
Keyword(s):  
Sic Ceramics ◽  
Fabrication And Characterization ◽  
Porous Sic

Low Temperature Fabrication and Characterization of Porous SiC Ceramics Using Polycarbosilane as Binder

2007 ◽  
Vol 336-338 ◽  
pp. 1090-1092 ◽  
Author(s):  
Qing Song Ma ◽  
Xiao Dong Yu
Keyword(s):  
Particle Size ◽  
Low Temperature ◽  
Fracture Surface ◽  
Flexural Strength ◽  
Sic Ceramics ◽  
Fabrication And Characterization ◽  
Porous Sic

Polycarbosilane (PCS) and SiC powders, in which PCS acted as binder, were adopted as starting materials to fabricate porous SiC ceramics. During pyrolysis, PCS experienced an organicinorganic transformation and bonded SiC powders at a low temperature of 1273K. The flexural strength of porous SiC ceramics increased with increasing PCS content and shaping pressure, while the porosity decreased with increasing the PCS content, shaping pressure and particle size of SiC powders. The fracture surface of porous SiC ceramics was observed.

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.

Processing highly porous SiC ceramics using poly(ether-co-octene) and hollow microsphere templates

2011 ◽  
Vol 46 (10) ◽  
pp. 3664-3667 ◽  
Author(s):  
B. V. Manoj Kumar ◽  
Wentao Zhai ◽  
Jung-Hye Eom ◽  
Young-Wook Kim ◽  
Chul B. Park
Keyword(s):  
Hollow Microsphere ◽  
Sic Ceramics ◽  
Porous Sic ◽  
Highly Porous

scholarly journals Synthesis and characterization of (Ba, Yb) doped ceria nanopowders

2011 ◽  
Vol 5 (2) ◽  
pp. 69-72 ◽  
Author(s):  
Branko Matovic ◽  
Jelena Pantic ◽  
Jelena Lukovic ◽  
Svetlana Ilic ◽  
Nadezda Stankovic ◽  
...  
Keyword(s):  
Room Temperature ◽  
Average Diameter ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Doped Ceria ◽  
Fixed Amount ◽  
Fluorite Type ◽  
Powder Properties ◽  
The Mean

Nanometric size (Ba, Yb) doped ceria powders with fluorite-type structure were obtained by applying selfpropagating room temperature methods. Tailored composition was: Ce0.95-xBa0.05YbxO2-? with fixed amount of Ba - 0.05 and varying Yb content 'x' from 0.05 to 0.2. Powder properties such as crystallite and particle size and lattice parameters have been studied. R?ntgen diffraction analyses (XRD) were used to characterize the samples at room temperature. Also, high temperature treatment (up to 1550?C) was used to follow stability of solid solutions. The mean diameters of the nanocrystals are determined from the full width at half maxima (FWHM) of the XRD peaks. It was found that average diameter of crystallites is less than 3 nm. Williamson- Hall plots were used to separate the effect of the size and strain in the nanocrystals.

Development of ethylene glycol-based gelcasting for the preparation of highly porous SiC ceramics

2020 ◽  
Vol 46 (6) ◽  
pp. 7896-7902 ◽  
Author(s):  
Yicheng Jin ◽  
Biao Zhang ◽  
Feng Ye ◽  
Haoqian Zhang ◽  
Zhaoxin Zhong ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Sic Ceramics ◽  
Porous Sic ◽  
Highly Porous

The effect of acid activation and calcination of halloysite on the efficiency and selectivity of Pb(II), Cd(II), Zn(II) and As(V) uptake

Clay Minerals ◽  
2016 ◽  
Vol 51 (3) ◽  
pp. 385-394 ◽  
Author(s):  
Paulina Maziarz ◽  
Jakub Matusik
Keyword(s):  
Photoelectron Spectroscopy ◽  
Active Sites ◽  
Structural Changes ◽  
Selective Adsorption ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Acid Activation ◽  
Subsequent Formation ◽  
X Ray ◽  
Mineral Structure

AbstractThe present study investigated the efficiency and mechanisms of aqueous Pb(II), Cd(II), Zn(II) and As(V) adsorption on natural (H), calcined (HC), and acid-activated halloysite (HA). The XRD and FTIR measurements indicated that the aluminosilicate framework was not affected by high-temperature treatment, in contrast to acid activation, which led to structural changes mainly in the tetrahedral sheet. The sorption of cations on H sample was low, though it was most effective for As(V). The X-ray photoelectron spectroscopy results suggested that removal of As(V) might be related to its reduction to As(III) involving oxidation of Fe(II) present in the mineral structure and/or iron minerals. The calcination enhanced halloysite sorption capacity for cations, while the As(V) sorption decreased. This was due to partial dehydroxylation and the subsequent formation of additional active sites. The acid treatment induced selective adsorption of Pb(II).

scholarly journals Characterization of the Materials Synthesized by High Pressure-High Temperature Treatment of a Polymer Derived t-BC2N Ceramic

Materials ◽  
2011 ◽  
Vol 4 (12) ◽  
pp. 2061-2072 ◽  
Author(s):  
Wallace R. Matizamhuka ◽  
Iakovos Sigalas ◽  
Mathias Herrmann ◽  
Leonid Dubronvinsky ◽  
Natalia Dubrovinskaia ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
High Pressure High Temperature
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