Surface Modification of Zirconia Substrate by Calcium Phosphate Particles Using Sol-Gel Method

Area of Science:

• Biomaterials Science
• Materials Engineering
• Surface Chemistry

Background:

• Zirconia is a widely used biomaterial due to its mechanical properties.
• Surface modification of zirconia is crucial for enhancing its biocompatibility and osseointegration.
• Biphasic calcium phosphates, like hydroxyapatite (HA) and tricalcium phosphate (TCP), are known for their osteoconductive properties.

Purpose of the Study:

• To develop a biphasic hydroxyapatite (HA) and tricalcium phosphate (TCP) coating on zirconia substrates.
• To investigate the effect of zirconia substrate porosity on the resulting HA/TCP coating microstructure.
• To optimize sol-gel parameters for controlled calcium phosphate deposition.

Main Methods:

• Sol-gel preparation of a calcium phosphate precursor solution.
• Spin-coating deposition of the sol onto both porous and dense zirconia substrates.
• High-temperature heat treatment (re-sintering at 1350 °C for porous, 750 °C for dense zirconia).

Main Results:

• Porous zirconia substrates yielded uniformly dispersed, isolated TCP and HA particles, with size influenced by sol viscosity.
• Dense zirconia substrates resulted in thick, nano-sized HA films but exhibited significant agglomeration and cracking.
• The microstructure of the HA/TCP coating is critically dependent on the underlying zirconia substrate's porosity.

Conclusions:

• Sol-gel method enables surface modification of zirconia with HA/TCP coatings.
• Controlling zirconia substrate porosity is key to tailoring the HA/TCP coating's microstructure.
• Further optimization is needed to mitigate agglomeration and cracking on dense zirconia surfaces for improved biomaterial applications.