Properties and Structure of Micro Porous Mullite-Corundum Refractory with High Strength

2010 ◽  
Vol 105-106 ◽  
pp. 23-26
Author(s):  
Juan Wu ◽  
Dao Yuan Yang ◽  
Kai Zhu ◽  
Rui Zhang
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Raw Materials ◽  
High Strength ◽  
Casting Process ◽  
Solid Content ◽  
Apparent Porosity ◽  
Corundum Refractory ◽  
Low Viscosity

Mullite- corundum ceramic was fabricated using bauxite and silica fume as raw materials by gel-casting process. The fluidity of the slurry, as well as strength, apparent porosity, pore size distribution, phase composition and microstructure of sintered specimen were studied. The results showed that: the slurry had low viscosity, good fluidity for casting if pH=9, dispersant 0.33wt% and solid content 60vol%; the strength of material came up to 165MPa even if the apparent porosity was about 30%; the samples were characterized by mullite 70%, corundum 22%, rutile 3%, glass phase only 5%, the size of majority grains was about 2μm, and most crystals with high melting point bonded directly; the average aperture was 264nm, the pore size distribution were divided into 2~30nm, 45~60nm and 1500~4000nm three regions. The distribution probability of nano- aperture was the largest, the volume of micron -aperture was the maximum, but all pores were less than 4μm in diameter, which suggested that the materials had micro porous characteristics. The microcrystalline, crystals combined directly and micro porous structure leaded to high strength of the refractory materials together.

Influence of Hipping Pressure on the Strength and the Porosity of Porous Copper

1991 ◽  
Vol 251 ◽  
Author(s):  
Atsushi Takata ◽  
K. Ishizaki ◽  
Y. Kondo ◽  
T. Shioura
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Young’S Modulus ◽  
Open Porosity ◽  
Structural Parameters ◽  
High Strength ◽  
Porous Copper ◽  
Different Temperatures ◽  
Hip Process

ABSTRACTOpen porous copper metals, which have high strength, high open porosity and well controlled pore size distribution, were produced by a hot isostatic press (HIP) process. They were sintered at different temperatures from 973 to 1273K under various HIPping pressures up to 200MPa. Pore size distribution and Young's modulus of the sintered samples were analyzed. The HIPped products have greater strength and higher open porosity than those of the normally sintered ones. The internal structural parameters such as pore size distribution were controlled by changing the HIPping pressure.

scholarly journals Conducting Membranes and Coatings made from Redispersable Nanoscaled Crystalline SnO2:Sb Particles

1998 ◽  
Vol 520 ◽  
Author(s):  
C. Goebbert ◽  
M. A. Aegerter ◽  
D. Burgard ◽  
R. Nass ◽  
H. Schmidt
Keyword(s):  
Thermal Treatment ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Sol Gel ◽  
Total Porosity ◽  
Solid Content ◽  
Visible Range ◽  
Inorganic Membranes ◽  
Separation Processes

ABSTRACTInorganic membranes prepared by the sol gel method are promising candidates for use as filters in separation processes. Conducting supported membranes and coatings have been produced from redispersable nanoscaled crystalline Sb-doped SnO2 powders with a Sb content up to 5 mole % (with respect to Sn). The crystalline particles are monosized (≅4 nm) and fully redispersable in aqueous solution at pH ≥ 8 with a solid content up to 70 wt. %. By thermal treatment at different temperatures and times, the pore size diameter of the material can be adjusted from 4 to 20 nm with a very narrow pore size distribution (∼ ±1 nm) and a total porosity of 63 %, practically independent of the sintering parameters. Uniaxial pressed substrates present similar characteristics with however larger pore size distribution (±5 nm) and 80 % total porosity. Their resistance decreases with sintering temperature and time down to 4 Ω (800 °C 8 h). Fully dispersed aqueous solutions of the powder (25 wt. %) were used to prepare transparent conducting coatings on glass or ceramics by spin-coating. After thermal treatment (1 hour at 550 °C) single layers 200 nm thick exhibited a typical specific electrical resistance ρ = 2.5·10−2 ωcm with transmission in the visible range measured against air of 90%.

Fabrication of Multilayer Tubular Nanoporous Ceramic Membranes via Gel-Casting Followed by Dip-Coating

2008 ◽  
Author(s):  
P. Ahmadian Namini ◽  
A. A. Babaluo ◽  
M. Akhfash Ardestani ◽  
E. Jannatduost ◽  
M. Peyravi
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Ceramic Membranes ◽  
Dip Coating ◽  
Solid Content ◽  
Porous Support ◽  
Gel Casting ◽  
Nano Alumina ◽  
Mercury Porosimeter

Multilayer tubular nanoporous ceramic membranes were successfully prepared via gel-casting followed by dip-coating. Tubular alumina porous support systems were manufactured by gel-casting method with pore size in the range of 100–600 nm. Interlayer and top-layer were fabricated with appropriate thickness, morphology and pore size distribution via dip-coating of submicron and nano alumina slurries respectively. The effects of the several parameters such as: solid content, dipping time, vacuum pressure, heating rate and number of coated layers on the structural properties of the prepared nanoporous ceramic membranes were studied to get an appropriate pore size and defect-free surface and then the optimum condition was presented. The morphology and surface quality of nanoporous ceramic membranes were investigated by optical microscopy (OM) and thickness of fabricated interlayer and top-layer were examined with scanning electron microscopy (SEM). Mercury porosimeter measurements were performed to determine the open porosity, pore size and pore size distribution (PSD) of nanoporous ceramic membranes.

Mineralogy and micromorphology of İznik ceramics

1998 ◽  
Vol 48 ◽  
pp. 181-189 ◽  
Author(s):  
S. Kapur ◽  
N. Sakarya ◽  
E. A. Fitzpatrick ◽  
M. Pagliai ◽  
G. Kelling ◽  
...  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Temperature Rise ◽  
Raw Materials ◽  
The Body ◽  
Uniform Temperature ◽  
Fibrous Minerals ◽  
Materials Used

AbstractThe study of İznik ceramics of different periods revealed that temperatures of about 800–900°C were produced during firing. Glass fragments added to the body for strengthening resulted in the formation of fibrous minerals as clusters in the pores and protruding in the glaze together with Ca and P rich minerals in the raw materials used. The pore size distribution of the pores indicates a uniform temperature rise and fall during the production of the microstructure.

scholarly journals Influences of composition of starting powders and sintering temperature on the pore size distribution of porous corundum-mullite ceramics

2005 ◽  
Vol 37 (3) ◽  
pp. 173-180 ◽  
Author(s):  
Li Shujing ◽  
Li Nan
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Sintering Temperature ◽  
Apparent Porosity ◽  
Volume Percentage ◽  
Air Atmosphere ◽  
In Situ Decomposition ◽  
Mullite Ceramics

Porous corundum-mullite ceramics were prepared by an in-situ decomposition pore-forming technique. Starting powders were mixtures of milled Al(OH)3 and microsilica and were formed into oblong samples with a length of 100mm and a square cross-section with edge size of 20mm. The samples were heated at 1300?C, 1400?C, 1500?C or 1600?C for 3h in air atmosphere, respectively. Apparent porosity was detected by Archimedes? Principle with water as a medium. Pore size distribution and the volume percentage of micropores were measured by mercury intrusion porosimetry. The results show that the pore morphology parameters in the samples depend on four factors: particle size distribution of starting powders, decomposition of Al(OH)3, the expansion caused by mullite and sintering. The optimum mode which has a higher apparent porosity up to 42.3%, well-distributed pores and more microsize pores up to 16.3% is sample No.3 and the most apposite sintering temperature of this sample is 1500?C.

scholarly journals Study of an alkali-activated binder based on tungsten mining mud and brick powder waste

2018 ◽  
Vol 163 ◽  
pp. 06002 ◽  
Author(s):  
Naim Sedira ◽  
João Castro-Gomes
Keyword(s):  
Compressive Strength ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Raw Materials ◽  
Weight Ratio ◽  
Alkali Activation ◽  
X Ray Diffraction ◽  
Brick Powder ◽  
Alkali Activated

Blends of Tungsten mining waste mud (TMWM) and brick waste powder (BP) with different dosages were used as precursors for the study of a new binder obtained by alkali-activation. The synthesis was obtained at 60ºC curing during the first 24 hours and at 20°C during the remaining period. A combination of sodium hydroxide (SH) and sodium silicate (SS) solutions was used with SS/SH weight ratio equal 1.5. The solid precursors/liquid activators weight ratio equal to 4. And the modules SiO2/Na2O increase with the increasing of BP dosages 5.21 and 5.59 for dosages 10% and 50%, respectively. Mineralogical characterisation of raw materials was carried out by X–ray diffraction (XRD). The effect of the dosage of BP on the compressive strength and pore size distribution of the new binder was investigated from 24 hours up to 28 days. The pore size distribution was obtained mercury intrusion porosimetry (MIP). The increase in the dosages of BP, between 10 to 50%, was followed by an increase in compressive strength, from 25 to 59 MPa, for all the tested ages. The binder matrix become more dense and compact with the gradually increase of BP dosages, as found out by MIP.

Effect of Manifold Geometry on the Physical Performance of the Hydroentangled Nonwovens

2011 ◽  
Vol 332-334 ◽  
pp. 1291-1294
Author(s):  
Xiang Qin Wang ◽  
Xiang Yu Jin ◽  
Qin Fei Ke
Keyword(s):  
High Pressure ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Physical Performance ◽  
Abrasion Resistance ◽  
Raw Materials ◽  
Simulation Data ◽  
Good Agreement

In this paper, two kinds of hydroentangled nonwovens made from the same raw materials and process but different high pressure manifolds is tested to investigate the effect of manifold geometry on the physical performance of products. The results show that the sample treated by slot type manifold has better properties, which has higher hydroentanglement intensity and better abrasion resistance, but no big difference with the pore size distribution. The results are in good agreement with our previous simulation data.

scholarly journals Determination of suitable raw materials for preparation of frost resistant brick body and its evaluation according to pore size distribution

2015 ◽  
Vol 123 (1441) ◽  
pp. 868-873
Author(s):  
Mikulas SVEDA ◽  
Matej KERESTUR ◽  
Radomir SOKOLAR ◽  
Lenka NEVRIVOVA ◽  
Stanislav UNCIK
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Raw Materials

The microstructure of functionalized poLyacrylonitrile beads for bioseparations

1990 ◽  
Vol 48 (4) ◽  
pp. 1094-1095
Author(s):  
Eduardo A. Kamenetzky ◽  
David A. Ley
Keyword(s):  
Aqueous Solution ◽  
Affinity Chromatography ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Surface Coverage ◽  
Vacuum Impregnation ◽  
Thin Sections ◽  
Selective Staining ◽  
Low Viscosity ◽  
Diamond Knife

The microstructure of polyacrylonitrile (PAN) beads for affinity chromatography bioseparations was studied by TEM of stained ultramicrotomed thin-sections. Microstructural aspects such as overall pore size distribution, the distribution of pores within the beads, and surface coverage of functionalized beads affect performance properties. Stereological methods are used to quantify the internal structure of these chromatographic supports. Details of the process for making the PAN beads are given elsewhere. TEM specimens were obtained by vacuum impregnation with a low-viscosity epoxy and sectioning with a diamond knife. The beads can be observed unstained. However, different surface functionalities can be made evident by selective staining. Amide surface coverage was studied by staining in vapor of a 0.5.% RuO4 aqueous solution for 1 h. RuO4 does not stain PAN but stains, amongst many others, polymers containing an amide moiety.

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