title: Effect of solid/solution ratio on apatite formation from CaSiO3 ceramics in simulated body fluid.
abstract: The effect of the solid/solution (S/S) ratio on apatite formation from CaSiO3 ceramics in simulated body fluid (SBF) was investigated. CaSiO3 ceramics with a Ca/Si ratio of 0.91 were prepared by sintering CaSiO3 powder coprecipitated from ethanol solutions of Ca(NO3)2. 4H2O and Si(OC2H5)4 using NH4OH as the precipitant. These ceramics were reacted with SBF at S/S ratios of 1.0, 2.5 and 8.3 mg/ml at 36.5 degrees C for various times. Formation of apatite was observed at all the S/S ratios after soaking for 1 day. The amount and microstructure of the apatite obtained at a S/S ratio of 8.3 mg/ml, however, differed largely from the product formed at the other two S/S ratios. The apatite formed at S/S = 8.3 mg/ml was of smaller particle size, formed in smaller amount and with less preferred orientation of the (001) of apatite crystals compared with those formed at S/S = 1.0 and 2.5 mg/ml. An increase of Ca and decrease of the P components occurred in the soaked SBF at S/S = 8.3 mg/ml, the changes being much more marked than with the other two S/S ratios. These differences in the concentration changes in SBF at different S/S ratios are attributed to the difference in the apatite formation from the CaSiO3 ceramics.
authors.affiliation: Department of Metallurgy and Ceramics Science, Tokyo Institute of Technology, O-okayama, Meguro, Tokyo 152-8552, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Iimori
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Kameshima
authors.forename: Atsuo
authors.initials: A
authors.lastname: Yasumori
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Okada
mesh_terms: D001031:Apatites / Q000032:analysis / Q000737:chemistry*; D040761:Biomimetic Materials / Q000737:chemistry; D001826:Body Fluids / Q000737:chemistry*; D017610:Calcium Compounds / Q000032:analysis / Q000737:chemistry*; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry*; D003102:Colloids / Q000032:analysis / Q000737:chemistry; D003460:Crystallization / Q000379:methods*; D008422:Materials Testing; D044367:Phase Transition; D017640:Silicates / Q000032:analysis / Q000737:chemistry*; D012996:Solutions; D013499:Surface Properties
chemical_list: D001031:Apatites; D017610:Calcium Compounds; D020099:Coated Materials, Biocompatible; D003102:Colloids; D017640:Silicates; D012996:Solutions; C031293:calcium silicate