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The densification mechanism of hydroxyapatite particles during spray pyrolysis with variable carrier gas rates of flow
Author(s) -
Cho Jung Sang,
Rhee SangHoon
Publication year - 2012
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.31975
Subject(s) - materials science , nucleation , chemical engineering , supersaturation , dissolution , nitric acid , pyrolysis , volumetric flow rate , spray pyrolysis , mineralogy , nuclear chemistry , nanotechnology , chemistry , metallurgy , organic chemistry , thermodynamics , thin film , physics , engineering
The densification mechanism of hydroxyapatite particles during spray pyrolysis with varying carrier gas flow rates was investigated. A calcium phosphate solution with a Ca/P ratio of 1.67 was prepared by dissolving calcium nitrate tetrahydrate and diammonium hydrogen phosphate in deionized water followed by the addition of nitric acid. Hydroxyapatite particles were then synthesized by spray pyrolysis at 1500°C with carrier gas flow rates of 10, 30, and 50 L/min, respectively. The lower the carrier gas flow rate, the smaller and denser the as‐prepared hydroxyapatite particles. Consequently, the lower flow rates produced particles with higher sinterability at 1100°C. The results can be explained in terms of the nucleation and growth mechanism based on the degree of supersaturation of hydroxyapatite in a droplet, which was dependent on the evaporating speed of nitric acid and water. The practical implication of these results is that highly sinterable hydroxyapatite powders can be synthesized via spray pyrolysis by reducing the carrier gas flow rate in a fixed temperature environment. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 493–500, 2012.