Back to results
US 4,376,168 AGranted
Phosphate of calcium ceramics
AssigneeNGK Spark Plugs Co., Ltd.
InventorsAkio Takami, Kazuo Kondo
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeNGK Spark Plugs Co., Ltd.
InventorsAkio Takami, Kazuo Kondo
Estimating the term…
A strong and biocompatible sintered phosphate of calcium ceramics are obtained by sintering a powdery material substantially consisting of phosphate of calcium having a Ca/P ratio of 1.4-1.75, e.g. apatite group and/or tricalcium phosphate, and not exceeding 15% by weight of CaO-P.sub.2 O.sub.5 frit having a Ca/P ratio of 0.2-0.75. Y.sub.2 O.sub.3 incorporation therein improves the bending strength of the ceramics. Furthermore, a P.sub.2 O.sub.5 -metal oxide frit wherein metal oxide being one or more selected from BaO, CaO, MgO, ZnO, NaO and K.sub.2 O provides a more improved bending strength. The Y.sub.2 O.sub.3 incorporation herein still improves the strength of the sintered product.
Phosphate of calcium ceramics obtained by sintering a composition essentially consisting of 0.5-15% by weight of P.sub.2 O.sub.5 -metal oxide frit and the balance of a powdery material substantially consisting of phosphate of calcium having a Ca/P atomic ratio of 1.4-1.75, said P.sub.2 O.sub.5 -metal oxide frit essentially consisting, in mol% calculated for the frit, of 40-75% of P.sub.2 O.sub.5 and 20-55% of one or more metal oxide selected from the group consisting of BaO, CaO, MgO, ZnO, Na.sub.2 O and K.sub.2 O, provided that the sum of P.sub.2 O.sub.5 and said metal oxide is not less than 90 mol%, said ceramics having a bending strength of at least about 1000 kg/cm.sup.2.
A process for producing phosphate of calcium ceramics which comprises a step of mixing 0.5-15% by weight calculated for the ceramics of CaO-P.sub.2 O.sub.5 frit having a Ca/P atomic ratio of 0.2-0.75 and the balance of a powdery material of phosphate of calcium having a Ca/P atomic ratio of 1.4-1.75, and a step of sintering the resulting mixture, said ceramics having a bending strength of at least about 1000 kg/cm.sup.2.
Dependencies are inferred from the claim text.