Surface characteristics of ZrO2-containing oxide layer in titanium by plasma electrolytic oxidation in K4P2O7 electrolyte

A study investigated the surface characteristics of ZrO2-containing oxide layer in titanium processed by plasma electrolytic oxidation (PEO) method. The present coating was performed at AC current density of 200 mA/cm2 in a K4P2O7 electrolyte with ZrO2 powder in order to incorporate ZrO2 particles into titanium oxide layer. Microstructural observation showed that the ZrO2 particles were homogeneously dispersed as well as the surface roughness increased after PEO coatings using the electrolyte with ZrO2 powder. Irrespective of the use of ZrO2 powder, however, the size and fraction of the micro pores found in the oxide layer remained constant when compared to the result of PEO process without ZrO2 powder. Regarding the biomimetic apatite formation, the ZrO2 particles incorporated were of great importance in triggering the occurrence and growth of biomimetic apatite onto titanium oxide surface in a simulated body fluid solution. This fact was due to high surface roughness of the titanium oxide as well as inherent activation of the ZrO2 particles to form biomimetic apatite.

► Incorporation of ZrO2 particles into oxide layer was successfully achieved via plasma electrolytic oxidation.
► Surface roughness of oxide layer increased with an aid of ZrO2 incorporation.
► Capability of oxide layer having ZrO2 particles to form biomimetic apatite was improved.