Alkoxide route for preparing hydroxyapatite and its coatings

Area of Science:

• Materials Science
• Inorganic Chemistry
• Biomaterials Engineering

Background:

• Hydroxyapatite (HAP) is a key biomaterial with applications in bone regeneration and dental implants.
• Developing efficient and controllable synthesis methods for HAP is crucial for its widespread use.
• Precursor chemistry significantly influences the properties and morphology of synthesized HAP.

Purpose of the Study:

• To investigate the preparation of hydroxyapatite (HAP) using novel precursor solutions.
• To explore the role of acetic acid in stabilizing precursor mixtures.
• To develop HAP coatings on alumina substrates via dip-coating.

Main Methods:

• Nuclear Magnetic Resonance (NMR), X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) were used for characterization.
• Stable precursor solutions of phosphorus (P2O5) and calcium (Ca glycoxide) were prepared in alcoholic solvents with acetic acid.
• Dip-coating method was employed to create HAP coatings on alumina substrates.

Main Results:

• Stable mixed solutions of P2O5 and Ca glycoxide precursors were achieved using acetic acid.
• An amorphous powder precursor was formed at ~150°C, which transformed into HAP upon calcination at 500°C.
• HAP coatings on alumina exhibited rough surfaces and an adhesion strength of approximately 10 MPa, with morphology dependent on preparation chemistry.

Conclusions:

• The study successfully demonstrated a method for preparing hydroxyapatite using stable precursor solutions.
• The dip-coating technique enabled the formation of HAP coatings with good adhesion strength.
• Control over precursor chemistry offers a pathway to tailor the morphology and properties of HAP coatings.