Bond-coating in plasma-sprayed calcium-phosphate coatings.

Area of Science:

• Biomaterials Science
• Materials Engineering
• Biomedical Engineering

Background:

• Hydroxyapatite coatings are crucial for biomedical implants, particularly on titanium substrates.
• Improving the mechanical integrity and biocompatibility of these coatings is an ongoing challenge.
• Utilizing natural sources like human teeth offers a sustainable approach to biomaterial production.

Purpose of the Study:

• To investigate the effect of a bond-coating on the mechanical properties of plasma-sprayed hydroxyapatite coatings.
• To evaluate hydroxyapatite powders derived from human enamel and dentine for coating applications.
• To assess the suitability of fluorine-rich apatites for medical device coatings.

Main Methods:

• Plasma-spraying of hydroxyapatite powders derived from human enamel and dentine onto titanium substrates.
• Application of a thin aluminum oxide/titanium dioxide (Al2O3/TiO2) bond-coating layer prior to the main hydroxyapatite coating.
• Surface preparation of titanium substrates included roughening via Al2O3 blasting.
• Mechanical property testing (e.g., bond strength) of the resulting coatings.

Main Results:

• The bond-coating significantly increased the mechanical properties of the hydroxyapatite coatings.
• For enamel-derived powder, mechanical strength increased from 6.66 MPa to 9.71 MPa with bond-coating.
• For dentine-derived powder, mechanical strength increased from 6.27 MPa to 7.84 MPa with bond-coating.
• Tooth-derived apatite powders exhibited high thermal stability, attributed to their fluorine content.

Conclusions:

• Bond-coating is an effective strategy to enhance the mechanical performance of plasma-sprayed hydroxyapatite coatings on titanium.
• Fluorine-rich apatites derived from human teeth are promising biomaterials for calcium phosphate coatings on medical devices.
• The described methods for powder production and particle shaping are cost-effective and reliable for producing high-quality plasma spray powders.