Optimizing calcium phosphates by the control of pH and temperature via wet precipitation

Youngjae Kim, Seon Yong Lee, Yul Roh, Jinhyeok Lee, Juyeun Kim, Yongwoo Lee, Junseok Bang, Young Jae Lee

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


A series of calcium phosphates synthesized through a wet precipitation route of hydroxylapatite (HAP) was investigated over a wide range of temperature and pH (25-80 °C, and pH 6.5-10.0) using a combination of microscopic and spectroscopic analyses. XRD and FTIR show that monetite and brushite are formed as a single phase at non-ideal conditions of HAP, respectively. From TGA results, it is found that brushite is converted to monetite at a range 175-200 °C when heated at the heating rate, 10 °C/min. This phase transformation is also observed when brushite is aged at pH 8.5 and 60 °C for 24 hr in solution. Morphology of brushite is sensitive to pH variation. At pH 6.5, tabular and platy crystals of brushite are observed whereas needle-like ones are predominant at pH 8.5. For HAP formed at pH 10.0, their shapes tend toward needle-like particles as temperature increases. HAP particles at pH 8.5 are very similar in morphology to HAP at pH 10.0, but their lengths are two or three times as great as those at pH 10.0. These observations demonstrate that desired phase and properties of calcium phosphates can be controlled by pH, temperature, and aging time through a wet precipitation method.

Original languageEnglish
Pages (from-to)10008-10016
Number of pages9
JournalJournal of Nanoscience and Nanotechnology
Issue number12
Publication statusPublished - 2015 Dec 1


  • Brushite
  • Hydroxylapatite (HAP)
  • Monetite
  • Temperature
  • pH

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • Biomedical Engineering
  • General Materials Science
  • Condensed Matter Physics


Dive into the research topics of 'Optimizing calcium phosphates by the control of pH and temperature via wet precipitation'. Together they form a unique fingerprint.

Cite this