| abstract |
A method of forming high strength glass fibers in a glass melter substantially free of platinum or other noble metal materials, products made there from and batch compositions suited for use in the method are disclosed. One glass composition for use in the present invention includes 50-75 weight % SiO 2 , 13-30 weight % Al 2 O 3 , 5-20 weight % MgO, 0-10 weight % CaO, 0 to 5 weight % R 2 O where R 2 O is the sum of Li 2 O, Na 2 O and K 2 O, has a higher fiberizing temperature, e.g. 2400-2900° F. (1316-1593° C.) and/or a liquidus temperature that is below the fiberizing temperature by as little as 45° F. (25° C.). Another glass composition for use in the method of the present invention is up to about 64-75 weight percent SiO 2 , 16-24 weight percent Al 2 O 3 , 8-12 weight percent MgO and 0.25-3 weight percent R 2 O, where R 2 O equals the sum of Li 2 O, Na 2 O and K 2 O, has a fiberizing temperature less than about 2650° F. (1454° C.), and a ΔT of at least 80° F. (45° C.). A forehearth for transporting molten glass from the glass melter to a forming position is disclosed. By using furnaces and/or forehearths substantially free of platinum or other noble metal materials, the cost of production of glass fibers is significantly reduced in comparison with the cost of fibers produced using a melting furnace lined with noble metal materials. High strength composite articles including the high strength glass fibers are also disclosed. |