Patent ID: 8074472

Claim:
A method of forming alumina-zirconia beads, comprising the steps of: (a) forming a slip comprised of about 50% to about 70% by weight water and about 30% to about 50% by weight of a mixture of metal oxides, said mixture comprised of: about 20% to about 40% by weight of alumina (Al 2 O 3 ), about 9% to about 12% by weight ceria, and about 51% to about 68% of monoclinic zirconia; (b) milling said slip; (c) adding manganese oxide (MnO) to said slip in a concentration of about 0.1% to about 1% by weight, based upon the final weight of said mixture of metal oxides; (d) adding an ammonia-containing binding agent to said slip at a concentration of about 1.1% by weight; (e) forming beads by dropping said slip into a calcium chloride (CaCl 2 ) solution wherein drops of said slip gel into beads in said calcium chloride (CaCl 2 ) solution; (f) washing said beads to remove said calcium chloride therefrom, said beads being washed until the calcium content of said beads (on a calcium oxide basis) is between about 0.01% and about 0.8% by weight to said weight of said mixture of said metal oxides; (g) drying said beads; and (h) firing said beads at a temperature between about 1,320° C. and about 1,400° C. for about 2 hours to about 8 hours.