Ceramic composite membranes based on Bi3Ru3O11 – Bi1,6Er0,4O3 for obtaining of oxygen

2021 ◽  
Vol 6 ◽  
pp. 22-28
Author(s):  
P. E. Dergacheva ◽  
◽  
I. V. Kulbakin ◽  
S. V. Fedorov ◽  
A. S. Lysenkov ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Ceramic Composite ◽  
Oxygen Permeability ◽  
Total Porosity ◽  
Composite Membranes ◽  
Ceramic Composites ◽  
Argon Atmosphere ◽  
Pure Oxygen ◽  
Total Conductivity ◽  
Temperature Dependence Of Conductivity

Using hot uniaxial pressing in an argon atmosphere with a stress of 35 MPa and with a holding at 800 °C for 1 hour, ceramic composites of Bi3Ru3O11 – 50, 65 wt % Bi1,6Er0,4O3 were obtained. It was found that phase composition of the composites does not change during gas chromatographic testing at 800 °C and well corresponds to the specified one. Microstructure of the obtained composites was tested and the formation of dense composites with a total porosity of less than 1% and with a uniform distribution of the Bi3Ru3O11 and Bi1,6Er0,4O3 components in bulk of material was demonstrated. Transport properties (total conductivity, oxygen fluxes and selectivity of separating oxygen over nitrogen) of the obtained composites at 600 – 800 °C had been investigated. Thus, at 800 °C the electrical conductivity of Bi3Ru3O11 – 50, 65 wt % Bi1,6Er0,4O3 was about 200 and 50 Ohm–1∙cm–1, respectively, while the metallic nature of their temperature dependence of conductivity is correlated to that for the Bi3Ru3O11. The value of oxygen permeability for the obtained ceramic composites of about 7∙10–9 mol·cm–1·s–1 at 800 °C, which is compared to other membrane materials based on bismuth oxide, demonstrated the potential of their further use in the tasks for obtaining of pure oxygen from air.

scholarly journals MICROSTRUCTURAL, PHYSICAL AND MECHANICAL ANALYSIS OF RHA PORE MODIFIED POROUS ALUMINA WITH ALUMINUM AS REINFORCEMENT

2019 ◽  
Vol 9 (1) ◽  
pp. 29-43
Author(s):  
Mohamad Aznan Mohamad Najib ◽  
Azmah Hanim Mohamed Ariff ◽  
Suraya Mohamad Tahir ◽  
Azizan As’arry ◽  
Norkhairunnisa Mazlan
Keyword(s):  
Ceramic Composite ◽  
Positive Impact ◽  
Sucrose Solution ◽  
Agricultural Waste ◽  
Porous Ceramic ◽  
Total Porosity ◽  
Linear Shrinkage ◽  
Ceramic Composites ◽  
Total Density ◽  
Failure Strength

Porous ceramics are being used in many industrial applications and processes that require extreme environment exposure due to its chemical inertness to corrosive medium and its ability to withstand high temperatures. Tailoring the porosity through pore modifier is one of the method available to ensure that the strength of ceramic is homogeneous. In order to improve the strength of the porous ceramic, the addition of aluminium powders was explored in this research. With the addition of agricultural waste source pore modifier and aluminium as reinforcement, the microstructure, linear shrinkage, porosity (open, closed and total), density, hardness and failure strength of this ceramic composite were examined. The ceramic composites were fabricated through powder metallurgy processing routes. Alumina, Al2O3 with the respective amounts of 0 to 10 wt.% (intervals of 10 wt.%) of RHA and 0 to 10 wt.% (intervals of 2 wt.%) of aluminum, Al, were mixed homogeneously with 12 wt.% of sucrose solution. The mixtures were compacted and heat-treated for 1 h at each of the soaking temperatures of 200°C, 600°C and 1000°C followed by full sintering at 1550°C for 2 h in a furnace. The results have shown that open and total porosity increases with increasing amounts of RHA and aluminum. Meanwhile, the linear shrinkage, close porosity, density, hardness and failure strength was reduced. In this research, the strength was expected to increase with the addition of aluminum. However, due to the increasing percentage of the total porosity with the increased addition of aluminum, the samples behave inversely. Phase transformations to mullite (3Al2O3. 2SiO2) were seen in this research with the addition of RHA. This phase formation helps to increase the overall strength of the ceramic composites, showing that 10 wt% addition of RHA have a positive impact, not only as a medium to modify the pore formation, but it also has a positive effect on the strength property of the ceramic composite.

Modelling of Electrical Conductivity of n-p Ceramic Composite Using Equivalent Circuits

1995 ◽  
Vol 411 ◽  
Author(s):  
Gyeong Man Choi ◽  
Seok Taek Jun
Keyword(s):  
Electrical Conductivity ◽  
Grain Size ◽  
Ceramic Composite ◽  
Composition Dependence ◽  
Equivalent Circuits ◽  
Total Conductivity ◽  
Fractional Change ◽  
Total Electrical Conductivity ◽  
Type Semiconductor ◽  
P Type

ABSTRACTComposition dependence of electrical conductivity of ceramic composite was analyzed using a ZnO(n-type semiconductor)-CuO(p-type semiconductor) composite as a model. The contributions from grain and grain boundaries to the total conductivity of the composite were determined. New equivalent circuits were proposed which represented the distribution and connection of n and p grains and the total electrical conductivity was analyzed using the proposed circuits. Dominant equivalent circuit changed with composition and the total conductivity was determined by the exponential fractional change of two equivalent circuits. Effect of grain size on the grain boundary and total conductivity were also examined.

Composition Dependence of The Electrical Conductivity of n-p Ceramic Composite

1994 ◽  
Vol 357 ◽  
Author(s):  
Seok-Taek Jun ◽  
Gyeong-Man Choi
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Grain Boundaries ◽  
Ceramic Composite ◽  
Composition Dependence ◽  
Volume Fraction ◽  
Ceramic Composites ◽  
Equivalent Circuits ◽  
Total Resistance ◽  
Impedance Response

AbstractElectrical properties of ZnO-CuO ceramic composites with varying composition were investigated. The electrical conductivity increased with increasing CuO volume fraction between 1 mol% to 95 mol%. Impedance response showed three semicircles, indicating three resistive elements contributing to the total resistance of the composite. A new model based on the equivalent circuits was developed to explain the contribution of grain boundaries to the resistance of the composite. The change of electrical conductivity was explained by the probability change of two equivalent circuits.

scholarly journals Simultaneous PAN Carbonization and Ceramic Sintering for Fabricating Carbon Fiber-Ceramic Composite Heaters

2019 ◽  
Vol 9 (22) ◽  
pp. 4945 ◽  
Author(s):  
Daiqi Li ◽  
Bin Tang ◽  
Xi Lu ◽  
Quanxiang Li ◽  
Wu Chen ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Thermal Performance ◽  
Ceramic Composite ◽  
Ceramic Composites ◽  
Indoor Climate ◽  
Climate Control ◽  
Ceramic Tiles ◽  
Ceramic Sintering ◽  
Physical Features ◽  
Pan Fibers

In this study, a single firing was used to convert stabilized polyacrylonitrile (PAN) fibers and ceramic forming materials (kaolin, feldspar, and quartz) into carbon fiber/ceramic composites. For the first time, PAN carbonization and ceramic sintering were achieved simultaneously in one thermal cycle and the microscopic morphologies and physical features of the obtained carbon fiber/ceramic composites were characterized in detail. The obtained carbon fiber/ceramic composite showed comparable flexural strength as commercial ceramic tiles. Meanwhile, the composite showed exceptional electro-thermal performance based on the electro-thermal performance of the carbonized PAN fibers, which could reach 108 ℃ after 15 s, 204 ℃ after 90 s, and 292 ℃ after 450 s at 5 V (2.6 A), thereby making the ceramic composite a good candidate as an indoor climate control heater, defogger device, kettle, and other heating element.

scholarly journals New Synthetic Methods of Novel Nanoporous Polycondensates and Excellent Oxygen Permselectivity of Their Composite Membranes

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 859
Author(s):  
Yu Zang ◽  
Toshiki Aoki ◽  
Masahiro Teraguchi ◽  
Takashi Kaneko ◽  
Hongge Jia ◽  
...  
Keyword(s):  
Contact Angle ◽  
Upper Bound ◽  
Oxygen Permeability ◽  
Membrane Surface ◽  
Composite Membranes ◽  
Synthetic Methods ◽  
Preparation Methods ◽  
First Time

Two kinds of novel nanoporous polycondensates (sc(Rf)) have been synthesized by two new preparation methods consisting of polycondensation and highly selective photocyclicaromataization of 1/3 helical cis-cis polyphenylacetylenes with polymerizable groups. By the original methods, new well-defined sheet polymers having nanopores or nanospaces have been synthesized for the first time. Their composite membranes, containing small amounts (1.0 wt%) of sc(Rf), had ultrahigh oxygen permeability (Po2 > 1000 barrer), and their plots were beyond the Robeson’s upper bound line in the graph of oxygen permselectivity (α = Po2/PN2) versus Po2. Both α and Po2 values were enhanced by adding only small amounts (1.0 wt%) of sc(Rf). One of the sc(Rf)s synthesized on the base membrane surface showed the best performance, i.e., Po2 = 5300 barrer and α = 2.5. The membrane surface was effectively covered by sc(Rf), judging from the contact angle values. It is thought that nanopores and nanospaces created in and between sc(Rf) molecules played an important role for the enhancement of both α and Po2/PN2.

Synthesis and Characterization of Porous ZrO2-Y2O3-TiO2 Ceramics Prepared by Coprecipitation

2012 ◽  
Vol 727-728 ◽  
pp. 1387-1392 ◽  
Author(s):  
Luan M. Medeiros ◽  
Fernando S. Silva ◽  
Juliana Marchi ◽  
Walter Kenji Yoshito ◽  
Dolores Ribeiro Ricci Lazar ◽  
...  
Keyword(s):  
Ceramic Composite ◽  
High Strength ◽  
Ceramic Composites ◽  
Rice Starch ◽  
X Ray Diffraction ◽  
Zirconia Ceramics ◽  
Pore Former ◽  
X Ray ◽  
Cold Pressed

Zirconium dioxide (zirconia) ceramics are known by its high strength and toughness and titanium dioxide (titania) ceramics has outstanding surface properties. The ceramic composite formed between the two oxides are expected to have advantages of both ceramics, especially when its surface area is increased by pores. In this work, ceramic composites of ZrO2-Y2O3-TiO2were synthesized by coprecipitation and rice starch was added as pore former in 10, 20 and 30 wt%. Powders were cold pressed as cylindrical pellets and sintered at 1500 °C for 01 hour and ceramics were characterized by techniques as Archimedes method for density measurements, X-ray diffraction and scanning electron microscopy. Results showed that pores are inhomogeneously distributed through ceramic bodies.

Numerical Studies on Microwave Heating of Thermoplastic-Ceramic Composites Supported on Ceramic Plates

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Tanmay Basak ◽  
Sankaran Durairaj
Keyword(s):  
Ceramic Composite ◽  
Ceramic Composites ◽  
Thermal Runaway ◽  
Ceramic Plate ◽  
Uniform Heating ◽  
Processing Rate ◽  
Numerical Studies ◽  
Element Simulation ◽  
Al2o3 Composite ◽  
Alumina Composite

A detailed theoretical analysis has been carried out to study efficient microwave assisted heating of thermoplastic (Nylon 66) slabs via polymer-ceramic-polymer composite attached with ceramic plate at one side. The ceramic layer or plate is chosen as Al2O3 or SiC. The detailed spatial distributions of power and temperature are obtained via finite element simulation. It is found that uniform heating with enhanced processing rate may occur with specific thickness of Al2O3 composite, whereas SiC composite leads to enhanced processing rate with higher thermal runaway for thick Nylon samples attached with Al2O3 plate. SiC composite is effective due to enhanced processing rate, whereas Al2O3 is not effective due to reduced processing rate for thin samples attached with Al2O3 plate. For samples attached with SiC plate, thermal runaway is reduced by SiC composite, whereas that is not reduced by Alumina composite. Current study recommends efficient heating methodologies for thermoplastic substances with ceramic composite to achieve a higher processing rate with uniform temperature distribution.

scholarly journals Preparation of Apatite-Wollastonite-Phlogopite glass-ceramic composites by powder sintering method

2013 ◽  
Vol 45 (3) ◽  
pp. 331-339
Author(s):  
A. Faeghi-Nia
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Glass Ceramic ◽  
Ceramic Composite ◽  
Ceramic Composites ◽  
Powder Sintering ◽  
Powdered Glass ◽  
Activation Energy Of Sintering ◽  
Sintering Method ◽  
Glass Ceramic Composite

An Apatite-Wollastonite-Phlogopite glass-ceramic composite, was developed by sintering and crystallization of the powdered glass. The non-isothermal and isothermal sintering kinetics were studied for this glass-ceramic. Hot-stage microscopy (HSM) measurements demonstrated that it is possible to sinter and crystallize this glass-ceramic with 80% relative density. The activation energy of sintering was analyzed using previously reported model of sintering and it was obtained Q=193.83 KjmolK-1. Also it was shown that the microstructure of sample is a function of particle size distribution.

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