AC vs. DC Electrophoretic Deposition of Hydroxyapatite on Titanium

TL;DR

This study compares AC and DC electrophoretic deposition methods for applying hydroxyapatite coatings on titanium, demonstrating that AC-EPD produces denser, more uniform coatings suitable for biomedical implants.

Contribution

It introduces a novel application of AC-EPD in non-aqueous medium to achieve superior hydroxyapatite coatings on titanium.

Findings

AC-EPD yields denser, more uniform coatings than DC-EPD.

Surface crack density is lower in AC-EPD coatings.

Coating thickness can be controlled by voltage and time.

Abstract

The bio-inertness of titanium and its alloys attracts their use as bone implants. However a bioactive coating is usually necessary for improving the bone bonding of such implants. In this study, electrophoretic deposition(EPD) of hydroxyapatite (HA) powder on titanium plate was performed using butanol as solvent under direct current (DC) and alternating current (AC) fields. The zeta potential of the suspensions was measured to understand their stability and the charge on the particles. Coating thickness was varied by adjusting the voltage and time of deposition. Surface morphology and cross section thickness were studied using scanning electron microscopy and image analysis software. Surface crack density was calculated from the micrographs. The results showed that the samples of similar thickness have higher grain density when coated using AC as compared to DC EPD. This facile but novel test proves the capability of AC-EPD to attain denser and uniform HA coatings from non-aqueous medium.