Nanostructured hydroxyapatite/TiO(2) composite coating applied to commercially pure titanium by a co-sputtering...

Area of Science:

• Materials Science
• Biomaterials Engineering
• Surface Chemistry

Background:

• Hydroxyapatite (HAP) coatings enhance biocompatibility of titanium implants.
• Titanium (Ti) is widely used in orthopedic and dental applications.
• Developing stable HAP/TiO(2) composite coatings is challenging due to material decomposition during processing.

Purpose of the Study:

• To demonstrate a co-sputtering approach for coating commercially pure Ti (CP-Ti) with nanostructured HAP/TiO(2) composite.
• To investigate the effect of sputtering pressure on the formation and stability of HAP/TiO(2) composite films.
• To optimize sputtering conditions for achieving desired Ca/P ratios and HAP integrity.

Main Methods:

• Co-sputtering of HAP/TiO(2) composite onto CP-Ti.
• Controlled variation of processing (Ar) pressure during sputtering.
• Analysis of plasma spectral emission to understand radical variations.
• Characterization of film composition, including Ca/P ratio and phase stability.

Main Results:

• HAP/TiO(2) composite films were successfully obtained at a sputtering pressure of 2.67 Pa.
• HAP decomposition into CaO was observed at lower sputtering pressures (0.53 Pa).
• The Ca/P ratio was maintained at approximately 1.66 at 2.67 Pa, consistent with stoichiometric HAP.
• Plasma spectral analysis indicated Ar pressure influences hydroxyl (OH) radical concentration, vital for HAP formation.

Conclusions:

• Sputtering pressure is a critical parameter for successful HAP/TiO(2) composite coating deposition.
• A processing pressure of 2.67 Pa is optimal for preventing HAP decomposition and ensuring coating integrity.
• The presence of hydroxyl radicals, influenced by Ar pressure, is essential for HAP formation during sputtering.