| abstract |
Solid, shaped and fired refractory articles, such as fibers and microspheres, of titanium dioxide are made by shaping, gelling, and firing titania sols. Said fibers can be made by extruding in air a viscous aqueous titania sol, and heating and firing the resulting green fiber to remove water, decompose and volatilize undesired constituents, and form a refractory fiber of polycrystalline titanium dioxide, which is useful, for example, to form refractory fabrics or as reinforcement for composites. Said microspheres can be made by dispersing droplets of an aqueous titania sol in an organic dehydrating liquid, separating the resulting green microspheres from the dehydrating liquid, and heating and firing the green microspheres to form solid refractory microspheres of polycrystalline titanium dioxide, which are useful, for example, in reflective signs or traffic marking surfaces. Said fired fibers and microspheres are preferably transparent to visible light with the titanium dioxide content thereof in its anatase form. |