Whitlockite ceramic
First Claim
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1. A translucent, isotropic, substantially pore-free polycrystalline ceramic consisting essentially of whitlockite containing within the crystal lattice thereof about 0.1 to 2.2 percent by weight sulfate ion and characterized by an average crystallite size in the approximate range 0.3 to 3 microns and a density greater than about 98 percent of the theoretical density of β
- -whitlockite.
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Abstract
A novel, polycrystalline whitlockite ceramic in either pore-free or porous form, processes for the preparation thereof and methods of using the same as biological implant materials are disclosed.
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Citations
21 Claims
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1. A translucent, isotropic, substantially pore-free polycrystalline ceramic consisting essentially of whitlockite containing within the crystal lattice thereof about 0.1 to 2.2 percent by weight sulfate ion and characterized by an average crystallite size in the approximate range 0.3 to 3 microns and a density greater than about 98 percent of the theoretical density of β
- -whitlockite.
- View Dependent Claims (2, 3, 4, 5, 11, 12, 13, 18, 20)
- 6. A polycrystalline foamed ceramic body consisting essentially of whitlockite containing within the crystal lattice thereof about 0.1 to 2.2 percent by weight sulfate ion and characterized by an average crystallite size in the approximate range 0.3 to 3 microns, a total pore volume in the approximate range 20 to 80 percent, said pore volume comprising a substantially uniform distribution of open pores having a pore size diameter in the approximate range 50 to 300 microns.
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17. A process for producing non-ceramic, crystalline whitlockite containing within the crystal lattice thereof about 0.1 to 2.2 percent by weight sulfate ion which comprises reacting calcium ion with phosphate ion in a molar ratio in the approximate range 1.2-1.5 to 1 in aqueous medium at a pH of about 10 to 12 to produce a gelatinous precipitate of calcium phosphate having a molar ratio of calcium to phosphorus in the approximate range 1.50-1.53 to 1, separating said gelatinous precipitate from the solution, washing said precipitate free of soluble salts with water, homogeneously suspending the washed precipitate in 1 to 3 percent (w/w) aqueous ammonium sulfate in the amount of about 10 to 20 ml. per gram of theoretically expected whitlockite ceramic, separating the precipitate from the ammonium sulfate solution, drying said precipitate and heating the dried precipitate in the approximate range 725°
- C. to 900°
C. for about 0.5 to 4 hours.
- C. to 900°
Specification