| 摘要 |
Inorganic oxides in the form of fibres of rectangular cross-section having a length/thickness ratio of at least 500:1 and a width/thickness ratio between 1:1 and 10:1 are prepared by spreading a colloidal dispersion of a lyophobic sol. on a smooth polished surface in the form of a 5-50 micron film, drying the wet film at 20 DEG -220 DEG C., whereby on drying fibres are formed, and thereafter firing the fibres at about 950 DEG C. to seal the capillaries therein. The inorganic oxide sol. has a pH of 1-10.1 and contains between 2 and 25% of oxide, the disperse phase being finer than 0,2 microns. Examples refer to the use of silica sols., with and without boric oxide, sols. of synthetic boron mica made by adding boric acid to a pH of 6, and a zirconia sol. containing minor amounts of thoria, alumina, zirconium acetate and oxychloride and calcium chloride.
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