Properties of multiple oxide‐bonded porous SiC ceramics prepared by an infiltration technique

Abstract

Multiple oxide‐bonded porous SiC ceramics were fabricated by infiltrating a porous powder compact of SiC and alumina with cordierite sol followed by sintering at 1300‐1400°C in air for 3 hours. The microstructures, phase components, mechanical properties, and air permeation behavior of the developed porous ceramics were examined and compared with materials obtained by the traditional powder processing route. The porosity, average pore diameter, and flexural strength of the ceramics varied from 33 to 37 vol%, ~12‐14 μm and ~23‐39.6 MPa, respectively, with variation in sintering temperature. The X‐ray diffraction results reveal that both the amount of cordierite and mullite as the binder increased with increase in sintering temperature. In addition, it was found that the addition of alumina in powder form effectively enhanced the strength due to formation of mullite in the bond phase in contrast to the samples prepared without alumina additive. To determine the suitability of the material in particulate filtration application, particle collection efficiency of the filter material was evaluated theoretically using single collector efficiency model.

Effects of Composite Sintering Additives: Al(OH)3+Y2O3+CaF2 on the Performance of Porous Mullite Oxide-Bonded SiC Ceramics

“…4(B), indicating this phenomenon is mainly due to the additive system rather than the sintering condition used in this study. This result indicates that such a composite sintering additive system could promote the mullite phase to preferentially grow along a specific axis, which might be in the same way as the formation of the rod-like mullite [27,28] and the mullite whisker [33,34] reported in other work. Combined with the element distribution in Fig.…”

“…Since mullite (3Al2O3•2SiO2) exhibits a similar thermal expansion coefficient to SiC [24], better mechanical properties, good oxidation/corrosion resistance and thermal stability [25,26], aluminium sources are introduced to react with the oxidation-derived SiO2 and form mullite phase. Aluminium source includes alumina [27][28][29], Kaolin [30], aluminium hydroxide [31,32], bauxite [33], fly ash [22,34] and aluminium isopropoxide [35].…”

“…Addition of MoO3 could further reduce the mullitization point to around 900 ℃. By carefully controlling the sintering condition, mullite rod or whiskers were observed with MoO3-contained additives [27,31,34] benefiting the enhancement of flexural strength of SiC ceramics.…”

Effects of SiC whisker addition on mechanical, thermal, and permeability properties of porous silica‐bonded SiC ceramics

“…Porous silicon carbide (SiC) ceramics have attracted attention not only in the academic field but also industrially due to their remarkable characteristics such as low bulk density, high melting point, high oxidation resistance, bio-inert characteristic, corrosion resistance, high chemical stability, excellent mechanical strength, high specific strength, high thermal shock resistance, tailored thermal conductivity, and controlled permeability. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] These characteristics have made porous SiC ceramics suitable candidates to perform a wide range of engineering applications including membranes for water purification and gas separation, 1,3,5,11,[16][17][18][19] ceramic carriers, 20 lightweight structural materials, 4,6,7,9 hot gas filters, 10,11,[21][22][23][24][25] catalytic supports, [26][27][28] and thermal insulators. [29][30][31][32][33][34]…”

Intrinsic microstructures of silica‐bonded porous nano‐SiC ceramics

“…Porous SiC‐based ceramics are extensively used in various industrial applications such as the purification process of air and water, bio‐implants, thermoelectric energy conversion devices, catalytic supports, and thermal insulation, owing to their excellent mechanical properties, high corrosion and oxidation resistances, and tunable thermal and electrical properties 1‐7 …”