Thermal conductivity of porous Alumina-20 wt% zirconia ceramic composites

Rezaee, Samaneh; Ranjbar, Khalil

doi:10.1016/j.ceramint.2020.03.224

Cited by 21 publications

(13 citation statements)

References 43 publications

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“…Rezaee et al 22 prepared porous alumina‐20 wt% zirconia ceramic composites with corn starch as the pore‐forming agent that exhibited total porosities, compressive strengths, and hardness values within the ranges of 9.5%–65%, 290‐60 MPa, and 1050‐77 HV, respectively. Macroporous Al 2 O 3 ceramics having total porosities, pore sizes, and diametrical compressive strengths within the ranges of 67%–76.7%, 200‐800 µm, and 5.9‐2.01 MPa, respectively, were developed by Prabhakaran et al 23 who utilized wheat powder as both gelling and pore‐forming agents.…”

Section: Introductionmentioning

confidence: 99%

Tailored pore structures and mechanical properties of porous alumina ceramics prepared with corn cob pore‐forming agent

Dele‐Afolabi

Hanim

Ojo-Kupoluyi

et al. 2020

Int J Applied Ceramic Tech

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In this work, the effects of porosity and different particle sizes of pore-forming agent on the mechanical properties of porous alumina ceramics have been reported. Different grades of porous alumina ceramics were developed using corn cob (CC) of different weight contents (5, 10, 15, and 20 wt%) and particle sizes (<63 µm, 63-125 µm and 125-250 µm) as the pore-forming agent. Experimental results showed that total porosity and pore cavity size of the porous alumina ceramics increased with rising addition of CC pore former. Total porosity increased with increasing particle size of CC with the Al 2 O 3-<63 CC 5 sample exhibiting the lowest total porosity of 41.3 vol% while the highest total porosity of 68.1 vol% was exhibited by the Al 2 O 3-125-250 CC 20. The particle size effect of CC on the mechanical properties revealed that diametral tensile strength and hardness of the porous alumina ceramics deteriorated with increasing particle size of CC pore former. The Al 2 O 3-<63 CC 5 sample exhibited the highest diametral tensile strength and hardness of 25.1 MPa and 768.2 HV, respectively, while Al 2 O 3-125-250 CC 20 exhibited the lowest values of 1.1 MPa and 35.9 HV. Overall, porous alumina ceramics with the smallest pore sizes under each particle size category exhibited superior mechanical properties in their respective categories.

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Section: Introductionmentioning

confidence: 99%

Tailored pore structures and mechanical properties of porous alumina ceramics prepared with corn cob pore‐forming agent

Dele‐Afolabi

Hanim

Ojo-Kupoluyi

et al. 2020

Int J Applied Ceramic Tech

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“…The highest strength was 3.82 MPa in Si01, and the compressive strength decreased with increasing amount of Si sludge, such that the compressive strength for the Si10 sample was 2.11 MPa. The mechanical properties of porous ceramics are predominantly influenced by the microstructural characteristics such as pore size distribution, shape, and openclosed pore ratio [21,22,32,33]. In this study, it was found that the bulk density decreased, the porosity increased, and the compressive strength decreased due to the formation of macropores with increasing amount of Si sludge substitution.…”

Section: Resultsmentioning

confidence: 74%

“…Hence, they are used in gas filters, catalyst supports, insulators, absorbers, and lightweight construction structures, because of their excellent thermal properties and lightweight porous structure [18]. For porous ceramics used as thermal insulating materials, ongoing research is focused on controlling the shape and size of the pores and enhancing the porosity to obtain high thermal insulation and excellent strength [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Thermal properties of porous ceramics manufactured by direct foaming using silicon sludge and silica fume

Son

Kang

Kim

2021

Journal of Asian Ceramic Societies

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In this study, waste silica fume was used as the raw material for manufacturing porous ceramics, and its mechanical and thermal properties required for application as thermal insulators were studied. For pore formation with direct foaming, Si sludge (0.01, 0.05, and 0.1 wt%) and NaOH aqueous solution (14 N) were used as the foaming agents. The porous ceramics sintered at 900°C showed an apparent porosity of 85.9-89.8%, and the specimen with 0.1 wt% Si sludge showed the highest apparent porosity of 89.8% and a bulk density of 0.24 g/cm 3 . Scanning electron microscopy results showed that with increasing Si sludge substitution, an open pore structure was formed because of the increase in the pore size from several tens to several hundreds of micrometers. The compressive strength decreased from 3.82 to 2.11 MPa as the amount of added Si sludge increased from 0.01 to 0.1%, respectively. The thermal conductivity was less than 1.0 W•m −1 •K −1 in the temperature range of 25-800°C, and the specimen with 0.1 wt% Si sludge showed a low thermal conductivity of 0.2-0.6 W•m −1 •K −1 . The thermal expansion coefficients were 17.1-22.4 × 10 −6 /K in the temperature range of 25-800°C.

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“…Unlike metals, due to the lack of sufficient free electrons, thermal conduction in ceramics is dominated by phonons (quantized unit of lattice vibrational energy). [31,32] The energy, frequency, and the collision probability of phonons would all increase with temperature, so the mean free path of phonons would be accordingly decreased, leading to the decrease in the thermal conductivity of AT ceramic. [32,33] During cooling stage, the cooling rate on the surface of the AT sample would be greater than that of the interior.…”

Section: Effect Of Grain Boundary Microcracks On the Mechanical Prope...mentioning

confidence: 99%

“…[31,32] The energy, frequency, and the collision probability of phonons would all increase with temperature, so the mean free path of phonons would be accordingly decreased, leading to the decrease in the thermal conductivity of AT ceramic. [32,33] During cooling stage, the cooling rate on the surface of the AT sample would be greater than that of the interior. As we all know, the lower the The density of microcracks is defined as the number of microcracks divided by the observed area [39,40] ; b) Values in parenthesis are the median microcrack width.…”

Section: Effect Of Grain Boundary Microcracks On the Mechanical Prope...mentioning

confidence: 99%

Influence of Cooling Rates on the Microstructure and Mechanical Properties of Aluminum Titanate Flexible Ceramic

et al. 2021

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Herein, aluminum titanate (Al2TiO5, AT) flexible ceramics with different cooling rates (program‐controlling cooling (10 and 20 °C min−1), air cooling (≈400 °C min−1), and water cooling (>1000 °C min−1) are fabricated by reaction sintering of Al2O3 and TiO2. The effect of cooling rates on microstructures and the mechanical properties of AT ceramics are systematically investigated. The microcrack width and density of AT ceramics with different cooling rates are statistically calculated. In addition, the effect of a microcracks structure on the mechanical properties of AT ceramics is deeply studied. Results show that the increase in cooling rate will increase the width and density of microcrack, leading to a suitable increase in flexibility and a slight decrease in strength. When AT is cooled in air, the best bending strain of 1.10% can be obtained, with a median microcrack width of 0.533 μm and a density of 6831.88 ± 374.87 N mm−2. It is hopeful that through this research, the effect of cooling rate on the mechanical properties of AT flexible ceramics can be deeply understood, and the strategy used in this research can be used in other exploration of similar material.

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Thermal conductivity of porous Alumina-20 wt% zirconia ceramic composites

Cited by 21 publications

References 43 publications

Tailored pore structures and mechanical properties of porous alumina ceramics prepared with corn cob pore‐forming agent

Tailored pore structures and mechanical properties of porous alumina ceramics prepared with corn cob pore‐forming agent

Thermal properties of porous ceramics manufactured by direct foaming using silicon sludge and silica fume

Influence of Cooling Rates on the Microstructure and Mechanical Properties of Aluminum Titanate Flexible Ceramic

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