| abstract |
PURPOSE: To provide thin silica flakes useful as a protective film for an article or a substrate for chromatography having excellent performance which is obtd. by subjecting hydrated alkali silicate particles to heating and post treating and have a uniform thickness and extremely small thickness. n CONSTITUTION: These thin silica flakes have respective substantially uniform thickness and the average thickness thereof is larger than 0 and ≤3.0 μm. The thin silica flakes are formed by the following method. Namely, (a) the hydrated alkali silicate particles are heated (adequately 475 to 525°C) and while the average thickness thereof is decreased larger than 0 and smaller than 3 μm, the particles are expanded to hollow microspheres having an average diameter of at least twice the initial average diameter, (b) these hallow microspheres are destroyed to form splinters, (c) these splinters are neutralized, washed and dried to form the hydrated thin silica flakes. (d) The hydrated thin silica flakes are fired (adequately 500 to 900°C) after the stage (c), by which the refractory thin silica flakes are formed. n COPYRIGHT: (C)1990,JPO |