scholarly journals Experimental Investigation on Flowability and Compaction Behavior of Spray Granulated Submicron Alumina Granules

ISRN Ceramics ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Abhisek Choudhary ◽  
Pandu Ramavath ◽  
Papiya Biswas ◽  
Nukala Ravi ◽  
Roy Johnson
Keyword(s):  
Relative Density ◽  
Surface Area ◽  
Flow Behavior ◽  
Compaction Pressure ◽  
High Surface ◽  
High Surface Area ◽  
Solid Loading ◽  
Alumina Powder ◽  
Flow Measurements ◽  
Spray Dried

Aqueous slurry with various solid loadings (up to 40 wt%) of alumina powder (D50 = 300 nm) with suitable rheological properties were spray dried into granules. Solid loading and feed rate of the slurry are found to have a prominent effect on the shape and size distribution of granules. Powder flow measurements exhibited a cohesive index of 28.45 signifying an extremely cohesive flow due to high surface area and irregular morphology. Finer sizes though it offers high geometrical surface area it leads to more surface contacts and hence, high interparticle friction. Spherical morphology achieved through optimum spray drying parameters significantly reduced the cohesive index to 6.45 indicating free flow behavior. Compaction studies of the spray-dried granules and corresponding plot of relative density versus compaction pressure revealed an agglomerate strength of 500 MPa followed by a plateau-like behavior reaching a maximum in the relative density of 59%-60% of the theoretical values.

Porous Al2O3/Al catalyst supports fabricated by an Al(OH)3/Al mixture and the effect of agglomerates

2005 ◽  
Vol 20 (3) ◽  
pp. 672-679 ◽  
Author(s):  
Zhen-Yan Deng ◽  
Yoshihisa Tanaka ◽  
Yoshio Sakka ◽  
Yutaka Kagawa
Keyword(s):  
Surface Area ◽  
Compaction Pressure ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Supports ◽  
Al Content ◽  
Starting Mixture ◽  
Mechanical And Electrical Properties ◽  
Uniform Microstructure ◽  
Compact Density

Porous Al2O3/Al catalyst supports were fabricated using a mixture of Al(OH)3 and Al powders, followed by pressureless sintering at a temperature of 600 °C in vacuum. Different pressures were used to prepare green compacts. High compaction pressure led to a high surface area and good mechanical and electrical properties for the sintered specimens. However, when the Al content in the sintered specimen exceeded a definite value, high compaction pressure decreased the surface area abruptly. Scanning electron microscopy observations revealed that agglomeration in the starting mixture has a significant effect on the microstructure of the sintered specimens. High compaction pressure greatly eliminated the agglomerates and led to a uniform microstructure for the sintered specimens. However, when the Al content in the starting mixture was too high, Al particles in the compacts prepared by the high pressure were largely sintered due to the high compact density so that most of the pores were closed. The present study indicates that a suitable compaction pressure is critical to obtaining superior Al2O3/Al supports.

scholarly journals Melt Infiltration Processing of Foams Using Glass-Forming Alloys

2002 ◽  
Vol 754 ◽  
Author(s):  
C. San Marchi ◽  
A. Brothers ◽  
D. C. Dunand
Keyword(s):  
Thermal Conductivity ◽  
Metallic Glass ◽  
Relative Density ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Glass Forming ◽  
Melt Infiltration ◽  
First Time ◽  
Infiltration Techniques

ABSTRACTProcessing of foams from bulk metallic glass (BMG) alloys, using melt infiltration techniques, is reported for the first time. Foaming methods based on infiltration of two types of pattern materials are described: investment of a continuous refractory yielding very low relative density structures (5% dense relative to the BMG), and investment of a discontinuous refractory pellet bed yielding higher relative density (50–60% dense relative to the BMG). Both methods are capable of producing foam structures; however high surface area and diminished thermal conductivity, especially in lower density structures, make vitrification of the alloy difficult.

Aerosol-assisted synthesis of mesoporous aluminosilicate microspheres: the effect of the aluminum precursor

2016 ◽  
Vol 40 (5) ◽  
pp. 4420-4427 ◽  
Author(s):  
Sonia Fiorilli ◽  
Valentina Cauda ◽  
Lucia Pontiroli ◽  
Chiara Vitale-Brovarone ◽  
Barbara Onida
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Mesoporous Aluminosilicates ◽  
Mesoporous Aluminosilicate ◽  
Aqueous Conditions ◽  
Accessible Porosity ◽  
Aluminum Precursor ◽  
Spray Dried ◽  
Aluminum Precursors

Spray-dried mesoporous aluminosilicates, with spherical morphology, high surface area and accessible porosity, have been synthesized under mild acidic aqueous conditions by using different aluminum precursors.

Synthesis of thermo-stable high surface area alumina powder from sol–gel derived boehmite

2007 ◽  
Vol 104 (1) ◽  
pp. 56-61 ◽  
Author(s):  
Seung-Moon Kim ◽  
Yun-Jo Lee ◽  
Ki-Won Jun ◽  
Jo-Yong Park ◽  
H.S. Potdar
Keyword(s):  
Surface Area ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Alumina Powder

Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

2019 ◽  
Author(s):  
Kailun Yang ◽  
Recep Kas ◽  
Wilson A. Smith
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Layer ◽  
Active Surface ◽  
Active Surface Area ◽  
High Concentration ◽  
Copper Electrodes ◽  
Surface Enhanced ◽  
Local Current

<p>This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO<sub>2</sub> electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO<sub>2</sub> electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO<sub>2</sub> electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer. </p> <p> </p>

scholarly journals Rugae-like FeP nanocrystal assembly on a carbon cloth: an exceptionally efficient and stable cathode for hydrogen evolution

Nanoscale ◽  
2015 ◽  
Vol 7 (25) ◽  
pp. 10974-10981 ◽  
Author(s):  
Xiulin Yang ◽  
Ang-Yu Lu ◽  
Yihan Zhu ◽  
Shixiong Min ◽  
Mohamed Nejib Hedhili ◽  
...  
Keyword(s):  
Gas Phase ◽  
Surface Area ◽  
Hydrogen Evolution ◽  
Hydrogen Generation ◽  
High Surface ◽  
High Surface Area ◽  
Catalytic Efficiency ◽  
Carbon Cloth ◽  
Nanocrystal Assembly

High surface area FeP nanosheets on a carbon cloth were prepared by gas phase phosphidation of electroplated FeOOH, which exhibit exceptionally high catalytic efficiency and stability for hydrogen generation.

High Surface Area NiCoP Nanostructure as Efficient Water Splitting Electrocatalyst for the Oxygen Evolution Reaction

2021 ◽  
pp. 111312
Author(s):  
Sisir Maity ◽  
Dheeraj Kumar Singh ◽  
Divya Bhutani ◽  
Suchitra Prasad ◽  
Umesh V. Waghmare ◽  
...  
Keyword(s):  
Surface Area ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
High Surface ◽  
High Surface Area

scholarly journals Fast synthesis of high surface area bio-based porous carbons for p-nitrophenol removal

MethodsX ◽  
2021 ◽  
pp. 101464
Author(s):  
Yichen Wu ◽  
Nan Zhang ◽  
Charles-François de Lannoy
Keyword(s):  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
Porous Carbons ◽  
Fast Synthesis

Synthesis of high surface area and functionalized nanoporous biocarbons and their efficiency for CO2 capture and supercapacitors

2021 ◽  
Author(s):  
Gurwinder Singh ◽  
Rohan Bahadur ◽  
Ajanya Maria Ruban ◽  
Jefrin Marykala Davidraj ◽  
Dawei Su ◽  
...  
Keyword(s):  
Energy Storage ◽  
Surface Area ◽  
Co2 Capture ◽  
Water Purification ◽  
High Surface ◽  
High Surface Area ◽  
Energy Storage And Conversion ◽  
Waste Biomass ◽  
Fabrication Technology ◽  
Significant Attention

Nanoporous biocarbons derived from waste biomass have created significant attention owing to their great potential for energy storage and conversion and water purification. However, the fabrication technology for these materials...

Sign in / Sign up

Export Citation Format

Share Document