High strength polycrystalline ceramic spheres
AssigneeWilliam Marsh Rice University
InventorsAndrew R. Barron, Kimberly A. DeFriend
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Abstract
A method for making hollow spheres of alumina or aluminate comprises: coating polymeric beads with an aqueous solution of an alumoxane, drying the beads so as to form an alumoxane coating on the beads; heating the beads to a first temperature that is sufficient to convert the alumoxane coating to an amorphous alumina or aluminate coating and is not sufficient to decompose the polymeric beads; dissolving the polymeric bead in a solvent; removing the dissolved polymer from the amorphous alumina or aluminate coating; and heating the amorphous alumina or aluminate coating to a second temperature that is sufficient to form a hollow ceramic sphere of desired porosity and strength. The hollow spheres can be used as proppants or can be incorporated in porous membranes.
Claims17
A method comprising propping open fractures in a subterranean formation with hollow, porous spheres of alumina or aluminate wherein the void volume is approximately 90% of the sphere volume and wherein the spheres have a hardness of at least 750 kg/mm2 on the Vickers hardness scale.
A wellbore fracture proppant comprising hollow, porous spheres of alumina or aluminate wherein the void volume is approximately 90% of the sphere volume and wherein the spheres have a hardness of at least 750 kg/mm2 on the Vickers hardness scale.
Dependencies are inferred from the claim text.