The effect of sago as binder in the fabrication of alumina foam through the polymeric sponge replication technique

Jamaludin, Abdul Rashid; Kasim, Shah Rizal; Ismail, Ahmad Kamal; Abdullah, M. Z.; Ahmad, Zainal Arifin

doi:10.1016/j.jeurceramsoc.2014.12.005

Cited by 29 publications

(27 citation statements)

References 35 publications

(29 reference statements)

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“…Figure B corresponds to the XRD diagram of the as sintered disks, prepared with a CG content of 50 wt%. The corundum crystalline structure is well identified, justifying the later use of 3.96 g/cm 3 as the density ρ s of the solid phase constituting the final alumina product, when calculating the overall porosity P .…”

Section: Resultsmentioning

confidence: 80%

“…According to the model developed by Gibson and Ashby, abbreviated with GA in the following, the relation between the compressive strength of a porous material (σ) and its relative density

(\frac{ρ_{a}}{ρ_{s}} = 1 - P)

, with P being the total porosity, is given by the equation:

\frac{σ}{σ_{f}} = c {()(, \frac{ρ_{a}}{ρ_{s}})}^{n}

where σ f is the modulus of rupture of the solid skeleton of which the porous material is made, c a dimensionless geometric constant and the exponent n equals 1.5 for an open‐cell structure, and ranges from 1 to 1.5 for closed‐cell structure. A linear fitting, of the present data, with respect to Equation , using a double log plot, yields; n = 3.407, and c = 0.629, with R 2 = 0.992, where a value of 400 MPa was taken for the flexural strength, σ f , of the alumina composing the solid phase of the porous samples . The obtained value of n is outside the [1‐1.5] range: it is closer to the 1.5 exponent (characteristic for open porous structures) than the 1 exponent (the minimum extremity of the range [1‐1.5] of exponents expected by the GA model for closed porous structures).…”

Section: Resultsmentioning

confidence: 99%

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The preparation and characterization of porous alumina ceramics using an eco‐friendly pore‐forming agent

Alzukaimi

Jabrah

2018

Int J Applied Ceramic Tech

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This work presents the preparation of porous alumina ceramics through the sacrificial phase method, using an eco-friendly material, namely waste coffee grounds, as a pore-forming agent. The effects of coffee grounds content in the green ceramic bodies on the linear and volumetric shrinkage, as well as the total and open porosity of the sintered product, were evaluated. The influence of the resulting porosity on mechanical properties of the prepared porous alumina was determined using Brazilian disk compression test for the determination of the indirect tensile strength of the prepared samples. Microstructure and pores morphology were characterized by scanning electron microscopy. Porosities in the range 35-54 vol % were achieved, by varying the coffee grounds content from 0 to 50 wt% in the green bodies. The indirect tensile strength of the final obtained porous alumina ceramic decreased accordingly from 57.4 MPa to 17.7 MPa. K E Y W O R D S alumina, Brazilian test, green body, porous ceramics, sacrificial phase | INTRODUCTIONPorous ceramics possess interesting features that cannot be achieved by their metallic or polymeric counterparts, such as high thermal and chemical stability, high thermal insulation, and mechanical resistance. 1-3 These unique properties, along with the high surface area, low density, high permeability, high specific strength, low specific heat, and low thermal conductivity (which are associated with the presence of pores, and therefore cannot be offered by the dense state), in addition to biocompatibility; make them typical for applications such as high-temperature insulation, gas combustion burners, catalyst carriers, filters for molten metals and hot corrosive gases, bone scaffolds, bioreactors, electrodes in fuel cells, chemical sensors, metal and polymer matrix composites, water filtration as well as lightweight building materials. [2][3][4] There exists a number of methods for the fabrication of these materials, such as partial sintering, replication technique (using natural and artificial templates), sacrificial fugitives (sacrificial phase or space holder technique), direct foaming, paste extrusion of ceramic powders, rapid prototyping techniques, sintering of hollow spheres, gel casting, connected rods and fibers, bonding techniques, sol-gel and starch consolidation. 2,[5][6][7][8][9][10] In the sacrificial phase technique, a mixture consisting of the ceramic powder, or its precursors, and a fugitive material, acting as a pore-forming agent (PFA), is prepared, and a green body is formed. To obtain a porous structure, the PFA, depending on its nature, is removed by several methods, including thermal methods such as pyrolysis, evaporation, and sublimation, or chemical methods such as washing by water and leaching by acids. 3,8,11 Then, the resulting product is sintered to obtain a porous ceramic. Many types of synthetic and natural materials, employed by the sacrificial phase technique and used as fugitives or pore formers (porogen agents, space-holders, or PFAs), are reported in the...

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Section: Resultsmentioning

confidence: 80%

“…According to the model developed by Gibson and Ashby, abbreviated with GA in the following, the relation between the compressive strength of a porous material (σ) and its relative density

(\frac{ρ_{a}}{ρ_{s}} = 1 - P)

, with P being the total porosity, is given by the equation:

\frac{σ}{σ_{f}} = c {()(, \frac{ρ_{a}}{ρ_{s}})}^{n}

Section: Resultsmentioning

confidence: 99%

The preparation and characterization of porous alumina ceramics using an eco‐friendly pore‐forming agent

Alzukaimi

Jabrah

2018

Int J Applied Ceramic Tech

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“…Another processing route to manufacture open‐cell foams is the sponge replication technique, which is widely applied in the fabricating of open‐celled ceramic foams . The sponge replication technique was established by Schwartzwalder et al This technique is widely applied in the fabrication of ceramic foams, and it allows to obtain high porosity.…”

Section: Introductionmentioning

confidence: 99%

Open‐Cell Aluminum Foams by the Sponge Replication Technique: A Starting Powder Particle Study

2020

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Open-cell aluminum foams are manufactured by a sponge replication technique, and the effect of aluminum particles with different shapes and particle sizes on foam properties is studied. It is found that aluminum powder with spheroidal particles leads to aluminum foams with a lower strut porosity, a lower amount of alumina, and a higher compressive strength compared with foams manufactured from flaky, irregularly shaped aluminum powder. This effect is explained with the lower surface area of the first mentioned type of powder.

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“…Devido às suas inúmeras aplicações, estudos têm sido desenvolvidos para incrementar as técnicas de processamento dessas cerâmicas porosas, tais como: inclusão de fase orgânica [10,11]; método da réplica da esponja polimérica [12,13]; método do gelcasting associado à aeração [14,15]; entre outras [16,17]. Dentre os métodos, o gelcasting promove a formação de um reticulado tridimensional, a partir da reação de copolimerização que, quando associado à aeração, possibilita a obtenção de uma estrutura com paredes densas, sem defeitos e ao mesmo tempo com elevada porosidade [14,15,18].…”

Section: Introductionunclassified

Análise comparativa entre diferentes ensaios porosimétricos em alumina macroporosa

et al. 2018

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RESUMOCerâmicas macroporosas de alumina (Al 2 O 3 ) são estudadas devido às suas diversas aplicações como biomateriais para implantes ósseos, ânodos para célula combustível de óxido sólido, entre outras. Nesse sentido, a distribuição, tamanho e interconexão dos poros podem determinar características físicas e mecânicas dessas cerâmicas. Assim sendo, o objetivo desse trabalho foi analisar e comparar diferentes métodos de caracterizações porosimétricas em amostras macroporosas de Al 2 O 3 . Para isso, os métodos analisados foram intrusão de mercúrio (PIM), método de Arquimedes (MA), análise de micrografias (AM) e ressonância magnética nuclear com pulsos de radiofrequência Carr-Purcell-Meiboom-Gill ( 1 H-RMN -CPMG). Amostras macroporosas de Al 2 O 3 foram obtidas pelo método de gelcasting modificado pela incorporação de esferas de polietileno, em diferentes quantidades. Os resultados foram tratados matematicamente e correlacionados pelo coeficiente de Pearson. As principais vantagens do MA foram a rapidez e a simplicidade na obtenção da porosidade aparente. No entanto, curvas de distribuição de tamanho de poros não são obtidas por esse método. As distribuições dos tamanhos dos poros obtidas por 1 H-RMN -CPMG foram semelhantes às do PIM. Essa semelhança é evidenciada pelo alto coeficiente de Pearson entre os dois métodos (r >0,962). As análises da forma e homogeneidade dos poros, bem como a porosidade aparente, foram melhores determinadas por AM. Porém, quando comparada com o método PIM, divergências quanto à distribuição de tamanho de poros foram observadas. Isso é evidenciado pelo baixo coeficiente de Pearson (r <0,048). Pode-se assim concluir que métodos não convencionais na determinação da porosidade ( 1 H-RMN -CPMG e AM) podem ser utilizados alternativamente aos convencionais (PIM e MA) na caracterização de materiais macroporosos.Palavras-chave: porosimetria, ressonância magnética, intrusão de mercúrio, análise de micrografias. ABSTRACTMacroporous ceramics of Al 2 O 3 are being studied due their diverse applications (biomaterials, anode for solid oxide fuel cells, etc.). The pore distribution, size and interconnection are important parameters that can determine physical and mechanical characteristics of these materials. The aim of this study was analyze and compare different methods of porosimetry. For this, we used the mercury intrusion porosimetry (PIM), Archimedes method (MA), micrographic analysis (AM) and nuclear magnetic resonance with CPMG radiofrequency pulses ( 1 H-RMN -CPMG). Samples of macroporous Al 2 O 3 were obtained by the gelcasting method modified by incorporation of polyethylene spheres at different amounts. The results of these porosimetry methods were treated mathematically, and then the Pearson correlation between the pore size distributions were analyzed. The main advantage of the MA was the simplicity to obtain the apparent porosity, although this method did not provide the pore size distribution. The pore size distribution obtained by 1 H-RMN -CPMG was similar to those obtained by PIM. T...

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The effect of sago as binder in the fabrication of alumina foam through the polymeric sponge replication technique

Cited by 29 publications

References 35 publications

The preparation and characterization of porous alumina ceramics using an eco‐friendly pore‐forming agent

The preparation and characterization of porous alumina ceramics using an eco‐friendly pore‐forming agent

Open‐Cell Aluminum Foams by the Sponge Replication Technique: A Starting Powder Particle Study

Análise comparativa entre diferentes ensaios porosimétricos em alumina macroporosa

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