Aging effect on the phase evolution of water-based sol-gel hydroxyapatite

Area of Science:

• Materials Science
• Biomaterials Engineering
• Chemical Synthesis

Background:

• Hydroxyapatite (HAp) synthesis via sol-gel methods requires careful control of precursor solution aging.
• Aging time is critical for forming intermediate complexes necessary for apatite phase development.

Purpose of the Study:

• To systematically investigate the effect of aging time and temperature on hydroxyapatite formation using a water-based sol-gel process.
• To determine optimal aging parameters and elucidate the aging kinetics for low-temperature HAp fabrication.

Main Methods:

• Fabrication of hydroxyapatite using a water-based sol-gel process.
• Systematic study of aging effects by varying aging time and temperature.
• Monitoring solution pH to investigate aging kinetics and determine activation energy.

Main Results:

• Aging time required for apatite formation significantly decreases with increasing aging temperature.
• Long-term thermal aging was found to be detrimental to apatite formation.
• Optimal aging parameters were identified and mapped, with an apparent activation energy of 10.35 kcal/mol determined for the aging reaction.

Conclusions:

• The study successfully determined optimal aging conditions for hydroxyapatite formation via sol-gel synthesis.
• A phase evolution map provides guidance for controlling HAp phase development based on aging parameters.
• Understanding aging kinetics is key to optimizing low-temperature hydroxyapatite fabrication for biomaterial applications.