Preparation and characterization of magnesium/carbonate co-substituted hydroxyapatites

Iain Ronald Gibson, W. Bonfield

Research output: Contribution to journalArticle

121 Citations (Scopus)

Abstract

A new synthesis/processing method has been devised to produce magnesium/carbonate co-substituted hydroxyapatite ceramics that do not decompose to tricalcium phosphate (TCP) on sintering. Using this method, a series of magnesium/carbonate co-substituted hydroxyapatite (Mg/CO3-HA) compositions, containing between 0 and 0.35 wt % Mg and approximately 0.9 wt % CO3 were prepared. Sintering the Mg/CO3-HA compositions in a CO2/H2O atmosphere yields a single crystalline phase that appears to be identical to stoichiometric HA. In contrast, when the compositions were prepared in the absence of carbonate and were sintered in air, the phase composition was a biphasic mixture of HA and TCP e.g. for 0.25 wt % Mg substitution the phase composition was approximately 60%HA/40% TCP. Clearly, both the synthesis route and the processing (i.e. sintering) route are of importance in the production of a single-phase Mg/CO3-HA ceramic. Fourier transform infrared (FTIR) spectroscopy has indicated that the Mg/CO3-HA ceramics still contained carbonate groups after sintering at 1200 degreesC. Chemical analysis by X-ray fluorescence spectroscopy (XRF) and C-H-N analysis has shown that the cation/anion molar ratio (i.e. [Ca+Mg]/[P+C/2]) of the different compositions were 1.68(+/-0.01), which is equivalent to the Ca/P molar ratio of stoichiometric HA. Although the magnesium/carbonate co-substitution had a positive effect in preventing phase decomposition during sintering, it appeared to have a negative effect on the densification of the MgCO3-HA ceramics, compared to stoichiometric HA. (C) 2002 Kluwer Academic Publishers.

Original languageEnglish
Pages (from-to)685-693
Number of pages8
JournalJournal of Materials Science: Materials in Medicine
Volume13
Issue number7
DOIs
Publication statusPublished - 2002

Keywords

  • CALCIUM-PHOSPHATE MATERIALS
  • CARBONATED APATITE
  • MAGNESIUM-IONS
  • TOOTH ENAMEL
  • BONE
  • BEHAVIOR
  • POWDERS
  • IMPLANTS
  • MG

Cite this

Preparation and characterization of magnesium/carbonate co-substituted hydroxyapatites. / Gibson, Iain Ronald; Bonfield, W.

In: Journal of Materials Science: Materials in Medicine, Vol. 13, No. 7, 2002, p. 685-693.

Research output: Contribution to journalArticle

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abstract = "A new synthesis/processing method has been devised to produce magnesium/carbonate co-substituted hydroxyapatite ceramics that do not decompose to tricalcium phosphate (TCP) on sintering. Using this method, a series of magnesium/carbonate co-substituted hydroxyapatite (Mg/CO3-HA) compositions, containing between 0 and 0.35 wt {\%} Mg and approximately 0.9 wt {\%} CO3 were prepared. Sintering the Mg/CO3-HA compositions in a CO2/H2O atmosphere yields a single crystalline phase that appears to be identical to stoichiometric HA. In contrast, when the compositions were prepared in the absence of carbonate and were sintered in air, the phase composition was a biphasic mixture of HA and TCP e.g. for 0.25 wt {\%} Mg substitution the phase composition was approximately 60{\%}HA/40{\%} TCP. Clearly, both the synthesis route and the processing (i.e. sintering) route are of importance in the production of a single-phase Mg/CO3-HA ceramic. Fourier transform infrared (FTIR) spectroscopy has indicated that the Mg/CO3-HA ceramics still contained carbonate groups after sintering at 1200 degreesC. Chemical analysis by X-ray fluorescence spectroscopy (XRF) and C-H-N analysis has shown that the cation/anion molar ratio (i.e. [Ca+Mg]/[P+C/2]) of the different compositions were 1.68(+/-0.01), which is equivalent to the Ca/P molar ratio of stoichiometric HA. Although the magnesium/carbonate co-substitution had a positive effect in preventing phase decomposition during sintering, it appeared to have a negative effect on the densification of the MgCO3-HA ceramics, compared to stoichiometric HA. (C) 2002 Kluwer Academic Publishers.",
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AU - Bonfield, W.

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N2 - A new synthesis/processing method has been devised to produce magnesium/carbonate co-substituted hydroxyapatite ceramics that do not decompose to tricalcium phosphate (TCP) on sintering. Using this method, a series of magnesium/carbonate co-substituted hydroxyapatite (Mg/CO3-HA) compositions, containing between 0 and 0.35 wt % Mg and approximately 0.9 wt % CO3 were prepared. Sintering the Mg/CO3-HA compositions in a CO2/H2O atmosphere yields a single crystalline phase that appears to be identical to stoichiometric HA. In contrast, when the compositions were prepared in the absence of carbonate and were sintered in air, the phase composition was a biphasic mixture of HA and TCP e.g. for 0.25 wt % Mg substitution the phase composition was approximately 60%HA/40% TCP. Clearly, both the synthesis route and the processing (i.e. sintering) route are of importance in the production of a single-phase Mg/CO3-HA ceramic. Fourier transform infrared (FTIR) spectroscopy has indicated that the Mg/CO3-HA ceramics still contained carbonate groups after sintering at 1200 degreesC. Chemical analysis by X-ray fluorescence spectroscopy (XRF) and C-H-N analysis has shown that the cation/anion molar ratio (i.e. [Ca+Mg]/[P+C/2]) of the different compositions were 1.68(+/-0.01), which is equivalent to the Ca/P molar ratio of stoichiometric HA. Although the magnesium/carbonate co-substitution had a positive effect in preventing phase decomposition during sintering, it appeared to have a negative effect on the densification of the MgCO3-HA ceramics, compared to stoichiometric HA. (C) 2002 Kluwer Academic Publishers.

AB - A new synthesis/processing method has been devised to produce magnesium/carbonate co-substituted hydroxyapatite ceramics that do not decompose to tricalcium phosphate (TCP) on sintering. Using this method, a series of magnesium/carbonate co-substituted hydroxyapatite (Mg/CO3-HA) compositions, containing between 0 and 0.35 wt % Mg and approximately 0.9 wt % CO3 were prepared. Sintering the Mg/CO3-HA compositions in a CO2/H2O atmosphere yields a single crystalline phase that appears to be identical to stoichiometric HA. In contrast, when the compositions were prepared in the absence of carbonate and were sintered in air, the phase composition was a biphasic mixture of HA and TCP e.g. for 0.25 wt % Mg substitution the phase composition was approximately 60%HA/40% TCP. Clearly, both the synthesis route and the processing (i.e. sintering) route are of importance in the production of a single-phase Mg/CO3-HA ceramic. Fourier transform infrared (FTIR) spectroscopy has indicated that the Mg/CO3-HA ceramics still contained carbonate groups after sintering at 1200 degreesC. Chemical analysis by X-ray fluorescence spectroscopy (XRF) and C-H-N analysis has shown that the cation/anion molar ratio (i.e. [Ca+Mg]/[P+C/2]) of the different compositions were 1.68(+/-0.01), which is equivalent to the Ca/P molar ratio of stoichiometric HA. Although the magnesium/carbonate co-substitution had a positive effect in preventing phase decomposition during sintering, it appeared to have a negative effect on the densification of the MgCO3-HA ceramics, compared to stoichiometric HA. (C) 2002 Kluwer Academic Publishers.

KW - CALCIUM-PHOSPHATE MATERIALS

KW - CARBONATED APATITE

KW - MAGNESIUM-IONS

KW - TOOTH ENAMEL

KW - BONE

KW - BEHAVIOR

KW - POWDERS

KW - IMPLANTS

KW - MG

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DO - 10.1023/A:1015793927364

M3 - Article

VL - 13

SP - 685

EP - 693

JO - Journal of Materials Science: Materials in Medicine

JF - Journal of Materials Science: Materials in Medicine

SN - 0957-4530

IS - 7

ER -