Microstructure and mechanical property of synthesized hydroxyapatite prepared by colloidal process

Area of Science:

• Materials Science
• Ceramic Engineering
• Biomaterials

Background:

• Hydroxyapatite (HAp) is a key biomaterial with applications in bone regeneration and dental implants.
• Controlling the microstructure and mechanical properties of HAp ceramics is essential for their performance.
• Colloidal processing offers a route to achieve dense and homogeneous ceramic bodies.

Purpose of the Study:

• To investigate the effect of polycarboxylic acid ammonium dispersant concentration on the properties of synthesized hydroxyapatite (HAp).
• To optimize the colloidal processing of HAp for improved microstructure and mechanical strength.
• To evaluate the thermal stability of the HAp microstructure.

Main Methods:

• Synthesized hydroxyapatite (HAp) powder using a colloidal process.
• Prepared HAp slurries with varying concentrations of polycarboxylic acid ammonium dispersant.
• Characterized slurry viscosity, green and sintered HAp microstructure, and mechanical properties (bending strength).
• Annealed sintered HAp samples at temperatures ranging from 1200 to 1400 °C.

Main Results:

• The quantity of dispersant significantly influenced HAp slurry viscosity, microstructure, and mechanical properties.
• A uniform microstructure was achieved in both green and sintered HAp using 2 wt% dispersant, effectively preventing powder agglomeration.
• Homogeneous microstructures were maintained even after annealing at high temperatures (1200–1400 °C).
• Maximum bending strength of 88.5 MPa was recorded at an optimal dispersant concentration.

Conclusions:

• Polycarboxylic acid ammonium dispersant plays a critical role in controlling the colloidal processing of HAp.
• Optimized dispersant concentration leads to enhanced microstructural homogeneity and superior mechanical properties in HAp ceramics.
• The developed colloidal process is suitable for producing high-performance HAp for advanced applications.