Fabrication of ultra-high-porosity cordierite foams by the thermo-foaming of powder dispersions in molten D-glucose anhy
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Fabrication of ultra-high-porosity cordierite foams by the thermo-foaming of powder dispersions in molten D-glucose anhydrous Xin Li1, Yuanbing Li2,a), Ruofei Xiang1, Shujing Li2, Qirun Zhou1, Han Luo1 1
The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People’s Republic of China The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, People’s Republic of China; and National-provincial Joint Engineering Research Center of High Temperature Materials and Lining Technology, Wuhan University of Science and Technology, Wuhan 430081, People’s Republic of China a) Address all correspondence to this author. e-mail: [email protected] 2
Received: 4 November 2018; accepted: 4 January 2019
Cordierite foams were prepared by thermo-foaming of alumina–microsilica–talc powder dispersions in molten D-glucose anhydrous followed by reaction sintering at 1400 °C, which exhibited an interconnected cellular morphology and three-dimensional porous cell walls. The cordierite foam had a porosity of up to 96%, and its corresponding thermal conductivity was as low as 0.057 W/(mK). The foam structures showed a great promise for gas filtration and gas catalytic support. The formation of interconnected cellular morphology, the variations of cell wall thickness, and cell size were explained from the perspective of viscosity and weak points in this paper. The linear shrinkage of cordierite foams having a density of 0.102–0.226 g/cm3 was in the range of 13.0–6.9%. And the compressive strength (0.05–0.28 MPa) was determined by the large cell size (1.1–1.3 mm), ultra-high porosity (91–96%), and characteristic of cordierite.
Introduction Cordierite foam is widely used because of its unique performances, such as excellent thermal shock resistance, high melting point, high corrosion resistance, low thermal conductivity, low thermal expansion coefficient, and low dielectric constant [1, 2, 3]. During the past years, the most common route for producing reticulate cordierite foams is the replication method [4, 5, 6, 7]. This method is based on the impregnation of a polymer sponge with a ceramic suspension to produce a macroporous ceramic exhibiting the same porous morphology as polymer sponge. Direct foaming and gel casting are also reported for the preparation of cordierite foams [8, 9, 10]. Akpinar et al. reported a polymeric sponge replication method for the preparation of in situ cordierite foams [11]. The ceramic slurries containing kaolin, magnesia, and quartz mixtures were coated on a polymeric sponge and then using conventional and microwave sintering to obtain cordierite foams. Li et al. used kaolin, attapulgite, and magnesium oxide as starting materials with arabic gum added as a dispersant to prepare cordierite foam with a porosity of 87.65% by direct foaming and slip
ª Materials Research Society 2019
casting method, and the thermal conductivity was as low as 0.095 W/(mK) [12]. The difficulty in preparing high-porosi
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