Transparent alumina film from ultrafine alumina sol

Properties of boehmite and Al2O3 thin films prepared from boehmite nanofibres

“…Alumina is an important technical ceramic in industry and the films [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] have many applications. For example, the transparent thin films can be applied to not only opto-and photo-electronic fields [1][2][3][4] but also coatings for modifying the surface properties of the glasses, 5,6 plastics, 7 etc.…”

“…Alumina is an important technical ceramic in industry and the films [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] have many applications. For example, the transparent thin films can be applied to not only opto-and photo-electronic fields [1][2][3][4] but also coatings for modifying the surface properties of the glasses, 5,6 plastics, 7 etc. On the other hand, porous films are expected to be useful for the ultrafiltration of gas, 1,11 and aqueous 9,10 or non-aqueous solvents, 11 as inorganic films including alumina have generally high thermal and chemical stability, pressure resistance and long life time compared with traditional organic polymer films, and can also be employed as the substrate for osteoblast culture.…”

Aqueous Precursors

“…After being washed with water, the precipitate was peptized with acetic acid and then heated. The sol obtained consisted of particles less than 10 nm in diameter, and the alumina film prepared from the sol was transparent up to 1000 C (Kurokawa et al 1986). A use of the fine alumina powder itself to make an aqueous sol was also investigated using hydrochloric acid to stabilize the sol (Rohrsetzer et al 1998).…”

Fabrication of transparent self-supporting alumina films by homogeneous precipitation process

“…From this view point, Kurokawa et al has proposed a method for producing alumina films by using aluminum salts. 20) In the method, aluminum hydroxide is precipitated with the addition of base to an aluminum salt aqueous solution, then it is peptized with acid to produce alumina sol, and finally the alumina sol is converted to an alumina film with gelation that takes place with drying. Though this method works well on the film fabrication, the peptization is performed by refluxing the aluminum hydroxide precipitate at ca.…”

“…According to the previous work using aluminum hydroxide precipitate prepared by adding ammonia aqueous solution as a precipitator to aluminum salt aqueous solution, 20) the precipitate becomes transparent by performing peptization at 80°C. With the respect to the present work, the precipitate became also a transparent sol by peptizing at 80°C.…”