Kinetic model for alpha-tricalcium phosphate hydrolysis

Date

2002-08-01

Author

Durucan, Caner

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A mechanistic model for the kinetics of hydrolysis of alpha-tricalcium phosphate (alpha-Ca-3(PO4)(2) or alpha-TCP) to hydroxyapatite (Ca10-x(HPO4)(x)(PO4)(6-x)(OH)(2-x) or HAp) has been developed. The model is based on experimental hydrolysis rate data obtained using isothermal calorimetry. Analysis of the kinetic data according to the general kinetics models in terms of the fractional degree of reaction and time suggests the hydrolysis to be controlled by different rate-limiting mechanisms as reaction proceeds. Initially, the hydrolysis kinetics depend on the surface area of the anhydrous alpha-TCP. Subsequently, they change to a dependence on the rate of HAp product formation controlled by a nucleation and growth mechanism. The model predicts that HAp nuclei form at essentially one time and growth occurs in two dimensions, leading to a platelike morphology. The change in the reaction mechanism occurs at a fractional degree of hydrolysis, which does not change significantly with temperature in the range of 37degrees-56degreesC.

Subject Keywords

Materials Chemistry, Ceramics and Composites

URI

https://hdl.handle.net/11511/35458

Journal

JOURNAL OF THE AMERICAN CERAMIC SOCIETY

DOI

https://doi.org/10.1111/j.1151-2916.2002.tb00397.x

Collections

Department of Metallurgical and Materials Engineering, Article

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Citation Formats

C. Durucan, “Kinetic model for alpha-tricalcium phosphate hydrolysis,” JOURNAL OF THE AMERICAN CERAMIC SOCIETY, pp. 2013–2018, 2002, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/35458.