Fabrication of Porous Alumina Sintered Bodies by a Gelate-Freezing Method

Abstract

Ⱥɳ‫ك‬ՏệᗕǺȗȚএઃමȪɳɧɒᠭệΧǽΰ⓯ ᨀᅻ౯ɿ⚱ᨚӸᆒଉ ɿ୮‫ۑ‬ϱȖଉ ɿ≐ᗂӡᆒଉ গРগકগકрకકᮾ᳣ᲇ᮪ᑿ‫ׅ‬༔కકଗფࢫ567-0047 গРಊ⇹ቆలῡ᳇ɾˎ 8-1 ଉ গРগક᧳Ꮱᲇકᮾ᳣ཀࢫ567-0047 গРಊ⇹ቆలῡ᳇ɾˎ 8-1Porous alumina sintered bodies were fabricated by a new gelate-freezing method. The fabricated porous alumina sintered bodies possess highly continuous open pores, and a wide range of pore size 20-200 mm and porosity 30-70ಚ. Inside the alumina only a few micro voids were observed. Pore size and porosity were able to be controlled by the alumina and water content in the slurry, and by the cooling temperature and direction.

Fabrication and properties of ultra highly porous silicon carbide by the gelation–freezing method

“…The plastic mold was then immersed into ethanol baths at various temperatures of −70, −40, −30, −20 and −10 • C. The gels were frozen in a manner similar to that previously reported. [1][2][3] The sublimation of ice crystals in the frozen gel was carried out under vacuum in a freeze drier at 10-35 • C for 24 h (Tokyo Rikakikai Co., Ltd., Model FDU-2100, Tokyo, Japan). Green bodies with φ70 mm and 10 mm thick were obtained, according to the shape of mold.…”

“…[1][2][3] In the GF method, raw powder is firstly dispersed into water with a gelation agent. After gelation, the wet gel is immersed into cold ethanol, and ice crystals are formed, which results in the subsequent formation of pores.…”

The Effect of Polyvinyl Alcohol on the Microstructure and Permeability of Freeze‐Cast Alumina

“…The frozen material is then sublimed, resulting in oriented pore channels within the ceramic 9–11 . Freeze‐casting is a flexible processing method and has also been accomplished using nonaqueous slips 12 and gelled slips 13 . This technique is capable of producing pore volume fractions as high as 95 vol% 14 and pore sizes ranging from 5 μm to above 100 μm 11 .…”

Synthesis and mechanical properties of porous alumina from anisotropic alumina particles

“…Several methods for the fabrication of porous alumina ceramics have been studied for a variety of applications. [1][2][3][4][5] Recently, to enable energy savings, porous alumina ceramics have been proposed for use as high temperature insulators, for instance, as a porous clinker in steel refractories. Such refractories are able to easily maintain a high temperature in the furnace, which leads to lowered energy cost of making steel.…”