Linear Shrinkage, Strength and Porosity of Alumina-Based Ceramic Foam with Corn Starch as Pore Former

2021 ◽  
Vol 317 ◽  
pp. 75-80
Author(s):  
Nurul Farhana Abdul Rahman ◽  
Hamimah Abdul Rahman ◽  
Wan Muhammad Syahmi Wan Azhan ◽  
Nor Hamidah Yatim
Keyword(s):  
Flexural Strength ◽  
Corn Starch ◽  
Total Porosity ◽  
Linear Shrinkage ◽  
Ceramic Foam ◽  
Morphological Properties ◽  
Pore Former ◽  
Ceramic Foams ◽  
Dispersing Agent ◽  
Suitable Amount

In this study, ceramic foams were produced using starch consolidation casting method. This research focused on the preparation of alumina-based ceramic foam by using corn starch as a pore-forming agent. Preparation of alumina based ceramic foam is studied to observe the effect of the addition of corn starch on its physical, mechanical and morphological properties. The composition of the suspension used included 64–58 wt.% alumina, 55 wt.% deionised water and other materials, such as silica and polyethylene glycol (PEG), were used as additive and dispersing agent respectively. Corn starch was added at 4, 6, 8 and 10 wt.%. The samples were preheated for gelation and coagulation processes, then dried and sintered at 1250 °C for 2 h. The ceramic foam gave a linear shrinkage from 1.07% to 3.39%. The obtained flexural strength was between 0.594 and 1.996 MPa. The average total porosity ranged from 54.05% to 70.70%. This study found that the suitable amount of corn starch in alumina foam is 4 wt.% because the resulting porosity values and flexural strength are appropriate for ceramic foams.

Study on the Composite Strengthening Effect of Talc and Kyanite Addition on Corundum–Mullite Based Ceramic Foam

2011 ◽  
Vol 197-198 ◽  
pp. 429-435 ◽  
Author(s):  
Shu Jun Ji ◽  
Xue Yi Guo ◽  
Jian Xiong Dong ◽  
Peng Su
Keyword(s):  
Flexural Strength ◽  
Ceramic Foam ◽  
Shrinkage Rate ◽  
Strengthening Effect ◽  
Ceramic Foams ◽  
Impregnation Process ◽  
Foam Ceramic ◽  
Sintering Shrinkage ◽  
Original Formula

Corundum–mullite based ceramic foams were prepared by adopting foam impregnation process with raw talc and kyanite as modifiers. By comparing the sinters strength among the original formula with and without talc and kyanite added, it can be seen that when 6wt% raw talc was added, the compressive and flexural strength of the sintered foam ceramic bodies are increased by 108.9% and 33% respectively more than the original formula. Adding 4wt% ball-milled kyanite on this basis, the compressive and flexural strength were further elevated 20.1% and 29.1%, respectively, and meanwhile, the sintering shrinkage rate was dropped by 54.2%.

scholarly journals The effect of polymeric template density and solid loading on the properties of ceramic foam

2009 ◽  
Vol 41 (3) ◽  
pp. 319-327 ◽  
Author(s):  
M.A.A.M. Nor ◽  
H.M. Akil ◽  
Z.A. Ahmad
Keyword(s):  
Flexural Strength ◽  
Ceramic Foam ◽  
Solid Loading ◽  
Simple Modification ◽  
Polymeric Foam ◽  
Ceramic Foams ◽  
Replication Method ◽  
Ceramic Slurry ◽  
The Given ◽  
Polymeric Template

This paper studies the effect of various polymeric foam template densities and solid loadings on the properties of ceramic foam. The study was based on six different polymeric foam templates with densities ranging from 13.4 to 37.8 kg/m3. The templates were impregnated in ceramic slurry with solid loading ranging from 15 to 60 wt. %. Effects of polymeric foam template density and solid loading quantity were evaluated based on porosity, density and mechanical properties of resulted ceramic foam. It was found that the density, porosity and flexural strength of ceramic foam seem to be independent from the template densities when the solid loading is less than 35 wt. %. For the given solid loading, i.e < 35 wt. %, the density and flexural strength are less than 1100 kg/m3 and 6 MPa, respectively, and porosities are higher than 40 %. The polymer replication method is a versatile method for the production of ceramic foams. It will allow the production of any desired properties of ceramic foam through a simple modification route.

Selective Catalytic Reduction of NOx over Zeolite-Coated Cordierite-Based Ceramic Foams: Water Deactivation

2008 ◽  
Vol 587-588 ◽  
pp. 810-814 ◽  
Author(s):  
Susana Dias ◽  
Fernando A. Costa Oliveira ◽  
C. Henriques ◽  
F.R. Ribeiro ◽  
Carmen M. Rangel ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Early Stage ◽  
Low Pressure ◽  
Membrane Reactors ◽  
Ceramic Foam ◽  
Catalytic Distillation ◽  
Ceramic Foams ◽  
Stage Of Development

The reactors used for Selective Catalytic Reduction (SCR) of NOx require low pressure drop structured catalyst packing. Structured packings, such as ceramic foams, are gaining increasing interest for application in low pressure drop reactors, membrane reactors and catalytic distillation units. In this work, cobalt ion exchanged mordenite (Co-HMOR)-coated cordierite-based foams produced by the replication method were evaluated for catalytic reduction of NOx with methane. The addition of 0.3 wt.% Pd to 2 wt.% Co-HMOR leads to a material that can convert 50 % NOx to N2 at 450 °C in a reaction mixture containing 2000 ppm CH4, 1000 ppm NOx, 5 % O2 and balance helium, at GHSV=17000 h-1. Although in an early stage of development, an efficient coating procedure was explored and different ways of exchange of Co and Pd cations into mordenite (Si/Al=10) were studied. Additions of 2 wt.% fumed silica enhanced adhesion of the zeolite onto the ceramic foam. Pd-exchanged Co-HMOR showed to be very sensitive to steam. A 50 % decrease in NOx conversion to N2 was observed after Pd/Co-HMOR samples were exposed at 450 °C to a reaction mixture containing 2 vol% H2O. Although further research is needed to ascertain the mechanism of this deactivation behaviour, agglomeration of Pd forming PdO particles is envisaged.

Preparation of Bimodal Porous Apatite Ceramics through Slip Casting Using Fine Hydroxyapatite Powders

2006 ◽  
Vol 317-318 ◽  
pp. 723-728 ◽  
Author(s):  
Yin Zhang ◽  
Yoshiyuki Yokogawa ◽  
Tetsuya Kameyama
Keyword(s):  
Flexural Strength ◽  
Size Range ◽  
Slip Casting ◽  
Fine Powder ◽  
Total Porosity ◽  
Solid Loading ◽  
Wet Milling ◽  
Hydrogen Phosphate ◽  
Optimum Amount ◽  
Porous Hydroxyapatite

A bimodal porous hydroxyapatite (HAp) body with high flexural strength was prepared through slip casting. HAp fine powder used in this study was synthesized by wet milling, drying and heating of a mixture of calcium hydrogen phosphate di-hydrate and calcium carbonate. The synthesized HAp powder was 0.320.05 μm in size and 38.10.8m2/g in specific surface area. The slip was prepared by adding deflocculant and foaming reagent. The optimum value for the minimum viscosity in the present HAp slip with respect to its solid loading and the optimum amount of the deflocculant were studied. The total porosity of the specimens obtained from a slip of 48 wt% HAp solid loading is in the range of 49 – 61vol %, and the resultant porous HAp sintered body had large spherical pores of 300 -m with interconnecting rectangular voids. Many small pores in the size range of 2-3 -m or below were observed in the specimen obtained by heating at 1100, and 1200 . The flexural strength of the bimodal porous HAp ceramics sintered at 1200 C showed a large value of 17.6 MPa, with a porosity of 60.5vol.

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.

scholarly journals The sintering kinetics of shellfish porcelain reinforced by sepiolite nanofibres

2018 ◽  
Vol 5 (10) ◽  
pp. 180483 ◽  
Author(s):  
Li Tian ◽  
Lijuan Wang ◽  
Kailei Wang ◽  
Yuedan Zhang ◽  
Jinsheng Liang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Diffusion Mechanism ◽  
Linear Shrinkage ◽  
Liquid Phase Sintering ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Fibre Pullout ◽  
Sintering Behaviour

The work investigated the effect of sepiolite nanofibres on mechanical properties and sintering behaviour of shellfish porcelain. Samples of shellfish porcelain reinforced by sepiolite nanofibres were fired in an electric furnace at 1150, 1200 and 1250°C for a period of 80, 100, 120 and 140 min. Sintered samples were characterized by flexural strength, fracture toughness, scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results showed that 2 wt% sepiolite nanofibres could increase the flexural strength and fracture toughness of the porcelain bodies through the fibre pullout and the weak interface mechanisms. Sintering activation energies were determined according to the linear shrinkage results. It is found that the liquid-phase sintering mechanism of shellfish porcelain with sepiolite nanofibres is a diffusion mechanism. Porcelain without sepiolite is controlled by volume diffusion, and eventually, the grain boundary diffusion began to appear with the increase of sepiolite addition.

Integrated Motile Orbital Implants Based on Ceramic Foam Scaffolds: Preparation and In Vivo Study

2012 ◽  
Vol 13 ◽  
pp. 41-53
Author(s):  
Oleg Smorygo ◽  
Viktoria Krasilnikova ◽  
Yuri Vialiuha ◽  
Vitaly Goranov ◽  
Yuri Kovalenko ◽  
...  
Keyword(s):  
Pore Size ◽  
Density Ratio ◽  
Alumina Ceramic ◽  
Ceramic Foam ◽  
In Vivo Studies ◽  
Internal Space ◽  
Open Cell ◽  
Ceramic Foams ◽  
Orbital Implants

Zirconia-alumina ceramic foam scaffolds with a nanocrystalline HAP coating were used for the preparation of integrated motile orbital implants. This study demonstrated that open-cell ceramic foams with enhanced strength-to-density ratio are quite suitable as biocompatible materials for the manufacture of orbital implants for post-enucleation syndrome treatment. In-vivo studies demonstrated that the application of a nanocrystallyne (not sintered) HAP coating facilitated the formation of dense fibrous capsule around the implant as well as the fast tissue ingrowth into the implant’s internal space. Orbital implants with the optimized pore size and HAP content were implanted to the animal’s eye cavity with their fixation to the extraocular muscles, and their motility was ensured.

scholarly journals Effect of soy protein isolate on the thermal, mechanical and morphological properties of poly (ɛ-caprolactone) and corn starch blends

2009 ◽  
Vol 28 (8) ◽  
pp. 824-829 ◽  
Author(s):  
P.D.S.C. Mariani ◽  
K. Allganer ◽  
F.B. Oliveira ◽  
E.J.B.N. Cardoso ◽  
L.H. Innocentini-Mei
Keyword(s):  
Soy Protein ◽  
Corn Starch ◽  
Soy Protein Isolate ◽  
Protein Isolate ◽  
Morphological Properties ◽  
Starch Blends

Use of Ash from the Incineration of Elephant Grass (Pennisetum purpureums shaum) into Clayey Ceramic

2012 ◽  
Vol 727-728 ◽  
pp. 993-998 ◽  
Author(s):  
A.M.F.D. Silva ◽  
L.S. Lovise ◽  
Sérgio Neves Monteiro ◽  
Carlos Maurício Fontes Vieira
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Large Scale ◽  
Chemical Characterization ◽  
Physical And Mechanical Properties ◽  
Linear Shrinkage ◽  
The Other ◽  
Industrial Processes ◽  
Elephant Grass ◽  
Calcium Compounds

Ashes generated in industrial processes are usually discarded and contribute to environmental pollution. Large scale incorporation into clayey ceramic products for civil construction, such as bricks and tiles, could be a permanent solution. Based on this rationale, this works has as its objective to characterize an ash waste from the incineration of elephant grass and to evaluate its incorporation into a clay to produce red ceramic. The waste was submitted to mineralogical and chemical characterization. Compositions were prepared with incorporation of the waste in amounts of up to 20 wt.% into the clay. Specimens were prepared by extrusion and fired in a laboratory furnace at 850°C. The physical and mechanical properties evaluated were: linear shrinkage, water absorption and flexural strength. The results showed that the waste is mainly composed of quartz and calcium compounds that sensibly reduce the linear shrinkage and does not change the other properties of the ceramic.

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