Effect of Experimental Conditions on the Chemical Composition of Hydroxyapatite Synthesized by Chemical Precipitation
- PDF / 258,686 Bytes
- 7 Pages / 432 x 648 pts Page_size
- 40 Downloads / 256 Views
MRS Advances © 2018 Materials Research Society DOI: 10.1557/adv.2018.105
Effect of Experimental Conditions on the Chemical Composition of Hydroxyapatite Synthesized by Chemical Precipitation Jorge López-Cuevas, Juan C. Rendón-Angeles, José L. Rodríguez-Galicia and Carlos A. Gutiérrez-Chavarría CINVESTAV-IPN, Unidad Saltillo, Calle Industria Metalúrgica No. 1062, Parque Industrial Saltillo Ramos Arizpe, Ramos Arizpe, Coahuila, México, CP 25900
ABSTRACT Hydroxyapatite [HAp, Ca5(PO4)3(OH)] was synthesized by chemical precipitation, using H3PO4 and Ca(OH)2 as chemical precursors. The precursors were slowly mixed in suitable proportions aiming to obtain Ca/P molar ratios of 1.5, 1.67 or 2.0 in the reacting suspension. This was followed by 21.5 h of aging. Both reaction and aging stages were carried out under an atmosphere of still ambient air and under continuous stirring, either at room temperature, 60 or 90 ºC. The precipitates were characterized by ICP-AES and XRD. The results suggested that the most suitable Ca/P molar ratio for the production of pure phase HAp is Ca/P = 1.67, as long as the initial Ca(OH)2 particle size and/or the suspension pH are carefully controlled, especially when the synthesis is carried out above room temperature.
*Corresponding author; Tel. +52 844 4389600; E-mail address: [email protected]
Introduction Over the years, hydroxyapatite [HAp, Ca5(PO4)3(OH)] has become the typical model for the mineral phase constituting the structural framework of the bones of all vertebrates [1]. HAp has been synthesized since many years ago for a variety of biomedical applications in surgery and dentistry, such as bone substitutions and repair, as a filler material, for biocements, etc. Among the methods reported in the literature for the synthesis of HAp, chemical precipitation is one of the most frequently used [2,3]. It is well-known [4] that the production of highly pure compounds using this method requires a detailed knowledge of the effect of the processing variables on the chemical composition of the reaction product. If these variables are not properly controlled, the precipitates will be constituted by a mixture of different calcium phosphates rather than by pure HAp. In this work, HAp was synthesized by chemical precipitation, using H 3PO4 and Ca(OH)2 as chemical precursors [3,5,6]. This method was chosen due to its inherent simplicity and low cost. It has been pointed out [5] that the most important processing variables involved in it are: initial Ca/P molar ratio, pH of the reacting suspension, 3851
Downloaded from https://www.cambridge.org/core. Access paid by the UCSB Libraries, on 07 Mar 2018 at 21:22:01, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/adv.2018.105
reaction temperature, mixing degree, post-reaction aging conditions, and H3PO4 addition rate. It has been mentioned [5] that in order to obtain stoichiometric HAp at 60 °C, it is necessary to use a Ca/P molar ratio of 1.67, which corresponds to
Data Loading...
