Microcrystalline transition metal oxide spinel articles
AssigneeMinnesota Mining and Manufacturing Company
InventorsDavid R. Kaar, Harold G. Sowman
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Abstract
Homogeneous, nonporous ceramic fibers containing at least one magnetically-unaligned, microcrystaline transition metal oxide spinel phase. The ceramic fibers may be used in polymeric, ceramic and metallic composites. Said ceramic spinel is produced by dispersing soluble inorganic and transition metal compounds in an aqueous mixture, concentrating to produce a viscous concentrate, shaping into the desired article, gelling the shaped article, and heating to produce the transition metal spinel article. Beads, bubbles, flakes, microspheres, films and granules may be made as well as fibers.
Claims17
A ceramic fiber consisting essentially of at least one magnetically-unaligned, microcrystalline, transition metal oxide spinel phase, said fiber being homogeneous and non-porous and having a surfce area of less than 1 m.sup.2 /g.
A ceramic fiber consisting essentially of at least one magnetically-unaligned, microcrystalline, transition metal oxide spinel pahse and at least one inorganic oxide selected from the group consisting of alumina, boria, phosphorus oxide, beryllia, zirconia, titania, silica, and other metal oxide which will not interfere with the formation or integrity of the spinel, said fiber being homogeneous and non-porous and having a surface area of less than 1 m.sup.2 /g.
A process for making a refractory spinel shaped article comprising the steps:
- a. providing an aqueous mixture containing soluble inorganic and transition metal salts, oxides, sols, dispersible colloids, or mixtures thereof,
- b. concentrating said mixture to a viscous concentrate,
- c. shaping the resulting viscous concentrate into a desired formed article,
- d. dehydratively gelling the formed article to provide a green non-refractory shaped article, and
- e. heating and firing the green shaped article in a temperature range of 820.degree. to 1000.degree. C. to provide said refractory spinel article;
- said refractory shaped article being a ceramic bead, bubble, flake, microsphere, film, granule, or continuous fiber consisting essentially of at least one microcrystalline transition metal oxide spinel phase, and said article being homogenous and non-porous.
A continuous fiber prepared according to the process of claim 15 and having a surface area of less than 1 m.sup.2 /g
A composite article comprising a polymeric, metallic, or ceramic component and at least one ceramic fiber component, said fiber consisting essentially of at least one magnetically-unaligned, microcrystalline, transition metal oxide spinel phase, said fiber being homogeneous and non-porous and having a surface area of less than 1 m.sup.2 /g.
A composite article comprising a polymeric, metallic, or ceramic component and at least one ceramic fiber component, said fiber consisting essentially of at least one magnetically-unaligned, microcrystalline, transistion metal oxide spinel phase, and at least one inorganic oxide selected from the group consisting of alumina, boria, phosphorus oxide, beryllia, zirconia, titania, silica, and other metal oxide which will not interfere with the formation or integrity of the spinel, said fiber being homogenous and non-porous and having a surface area of less than 1 m.sup.2 /g.
Dependencies are inferred from the claim text.