Preparation and characterization of magnesium aluminate (MgAl2O4) spinel ceramic foams via direct foam-gelcasting

Qiao, Jian; Wen, Yubin

doi:10.1016/j.ceramint.2019.09.020

Cited by 30 publications

(14 citation statements)

References 31 publications

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“…(1) By adding 10% Sws, the bulk density of the sample after burning is 1.257 g/cm 3 , the closed porosity is 16.31%, the compression strength is 18 MPa, and the thermal conductivity is 0.466 W/mK (1050°C). (2) When the addition amount of the walnut shell powder treated by the silica sol is 20%, the bulk density of the material after burning decreases to 1.029 g/cm 3 , and the thermal conductivity is 0.382 W/mK (1050°C). (3) rough SEM analysis, when using the silica solimpregnating walnut shell powder as the pore former, the surface structure of the walnut shell powder is effectively improved.…”

Section: Discussionmentioning

confidence: 99%

“…Magnesia insulation materials have gained considerable attention and have been extensively applied in steel, cement, glass, and ceramic, owing to low thermal conductivity, high refractoriness, high porosity, and high thermal shock resistance [1][2][3][4][5]. At present, the preparation methods of insulation materials mainly include the direct foaming method [6], burn-out method [7], and sol-gel method [8].…”

Section: Introductionmentioning

confidence: 99%

“…Du et al developed a high-porosity silicon nitride ceramic by the direct foaming method. Its porosity reached 92%-97%, but its compression strength was only 0.85-5.38 MPa [9]; Zou et al added nanometer aluminium oxide and zirconium oxide to prepare a nanoaperture magnesium oxide aggregate with a bulk density of 3.37 g/ cm 3 and a closed porosity of 4.3% [10]; Wu et al used magnesia lightweight aggregate to produce insulation materials, and the apparent porosity of the sample was 27.8% after sintering, and the compression strength was 68.4 MPa [11]; Obada et al prepared a ceramic membrane with enlarged pore by using ceramic clay and foaming agent PHDPE and found that the porosity reached 62% and the compression strength did not exceed 18 MPa [12]. e pore structure and the distribution in the material will directly affect the performance of the material.…”

Section: Introductionmentioning

confidence: 99%

“…Wei et al prepared porous alumina ceramics by impregnating rice husks with the zirconia sol. Compared with the sample prepared without any impregnated rice husk, the internal pore shape of the sample has changed significantly, and its intensity has been significantly improved [15]; Yang et al added the zirconia sol as an inorganic bond to prepare the mullite fiber ceramics, whose bulk density is 0.45-0.66 g/cm 3 and compression strength is 0.62-3.34 MPa [16]; Muto et al prepared an aluminium oxide thermal insulation material by using the hydrogel as the binding agent based on the house-of-cards structure as a template, and its thermal conductivity is 0.94 W/m K (1600°C), while the compression strength is 1.7 MPa [17].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Preparation of Magnesia Insulation Materials by Calcination of Walnut Shell Powder by Silica Sol Impregnation

Kang

Han

et al. 2021

Advances in Materials Science and Engineering

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In this paper, magnesia porous aggregate was prepared by the foaming method with potassium oleate as the foaming agent. Secondly, the walnut shell powder was impregnated with the silica sol as the pore forming agent, and then, a new magnesia insulation material was prepared by 1300°C sintering. By changing the amount of the walnut shell powder added, the mechanical properties and thermal properties of the materials after sintering were studied. The results show that the sample with 10% walnut shell powder impregnated without the silica sol has a compression strength of 12 MPa. A sample with 10% walnut shell powder treated with the silica sol has a compression strength of 18 MPa. With the increase in the amount of the walnut shell powder added after impregnation, the bulk density, compression strength, and thermal conductivity of the sample all showed a decreasing trend, and the apparent porosity showed an increasing trend. When the additive amount is 20%, the bulk density of the sample is 1.029 g/cm3, and the thermal conductivity is 0.382 W/m K (1050°C).

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Preparation of Magnesia Insulation Materials by Calcination of Walnut Shell Powder by Silica Sol Impregnation

Kang

Han

et al. 2021

Advances in Materials Science and Engineering

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“…Foams are characterized by a three-dimensional array of empty polygons; the most attractive type for catalysis applications are the open-cell foams, in which the cells are communicating. Among the preparation methods for ceramic foams [15], the "polymeric sponge method" [16,17] and the "bubble generation method" [18,19] are the most used, however the latter is suitable to prepare only small closed-cell foams. The preparation methods of metallic foams can be classified depending on the state of the metal to be used, liquid or solid.…”

Section: The Structuresmentioning

confidence: 99%

Recent Advances in Structured Catalysts Preparation and Use in Water-Gas Shift Reaction

et al. 2019

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The water-gas shift reaction plays a key role in hydrogen production processes from fossil sources and renewable biomass feedstock and can be considered as the first purification process of syngas. The water gas shift process is normally carried out in two adiabatic stages, of high and low temperature with an intersystem cooling. The two stages use two different catalytic systems, which present some critical issues, thus making extremely attractive the designing and implementing of new configurations. Innovative and highly active catalytic formulations along with more efficient reactor systems could provide the basis for the design of a single-stage process, resulting in a noticeable process intensification. In the last decades, much attention has been paid to the use of structured catalysts, which have numerous advantages, related to both fluid dynamics and heat transfer phenomena. Numerous papers have been published in which the competitive performances of structured catalysts have been shown with respect to conventional catalytic systems. In this brief review, we provide an overview of the most recent developments in the preparation of structured catalysts and use in the water gas shift reaction.

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Ultra‐lightweight 3D woven spacer integrated composites with stabilization of dielectric and robust mechanical properties at room and elevated temperatures

Zheng

Zhang

et al. 2022

Polymer Composites

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Polymer matrix composites with lightweight, low dielectric constant (ε) and dielectric loss tangent (tan δ), high‐temperature resistance, and excellent mechanical properties are urgently needed in the fields of aviation, aerospace, transportation, and wireless communication services. In this work, 3D woven spacer Kevlar/polyimide composites (3DKPC) with excellent dielectric properties and robust mechanical properties were designed and obtained by combining 3D weaving technology and thermal imidization process. Results show that the volume density of the prepared composites is as low as 0.24 g·cm−3, but its compressive strength can be up to 6.24 MPa. The dielectric constant and loss tangent of 3DKPC at room temperature are extremely low, with the value of ~1.32 and 6.9 × 10−3, respectively. Moreover, the compressive strength retention rate is more than 96% and the dielectric constant can be consistently lower than 1.36 when the temperature increases from 25 to 300°C, demonstrating the outstanding mechanical and dielectric stability of 3DKPC. In addition, as an application example of resulting composites, a microstrip antenna with 3DKPC as the substrate material was designed, followed by the simulation of its electromagnetic properties via High Frequency Structural Simulator. The results display that the gain of the microstrip antenna is 6.2 dB, which is superior to those of many other reported microstrip antennas, indicating that the 3DKPC proposed here has great application potential in aerospace, wireless communication, and other fields.

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Preparation and characterization of magnesium aluminate (MgAl2O4) spinel ceramic foams via direct foam-gelcasting

Cited by 30 publications

References 31 publications

Preparation of Magnesia Insulation Materials by Calcination of Walnut Shell Powder by Silica Sol Impregnation

Preparation of Magnesia Insulation Materials by Calcination of Walnut Shell Powder by Silica Sol Impregnation

Recent Advances in Structured Catalysts Preparation and Use in Water-Gas Shift Reaction

Ultra‐lightweight 3D woven spacer integrated composites with stabilization of dielectric and robust mechanical properties at room and elevated temperatures

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