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High strength polycrystalline ceramic spheres

  • US 20040224155A1
  • Filed: 02/06/2004
  • Published: 11/11/2004
  • Est. Priority Date: 02/06/2003
  • Status: Active Grant
First Claim
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1. A method for making hollow spheres of alumina or aluminate comprising:

  • a) coating polymeric beads with an aqueous solution of an alumoxane;

    b) drying the beads so as to form an alumoxane coating on the beads;

    c) heating the beads to a first temperature, wherein the first temperature is sufficient to convert the alumoxane coating to an amorphous alumina or aluminate coating and is not sufficient to decompose the polymeric beads;

    d) dissolving the polymeric bead in a solvent;

    e) removing the dissolved polymer from the amorphous alumina or aluminate coating; and

    f) 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.

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