Ki Ryong Shin

Development of titanium oxide layer containing nanocrystalline zirconia particles with tetragonal structure: Structural and biological characteristics.

This study investigated the microstructural, mechanical and biological properties of oxide layers containing tetragonal zirconia (t-ZrO2) particles on pure titanium produced by plasma electrolytic oxidation (PEO) process. For this purpose, PEO processes were carried out at an AC current density of 200mA/cm(2) for 180s in potassium pyrophosphate (K4P2O7) electrolytes with and without t-ZrO2 powder. Structural investigations using transmission electron microscopy exhibited that the present nanocrystalline oxide layer evidenced the successful incorporation of a myriad of t-ZrO2 particles working as an intermediate medium to reinforce the adhesion strength between the substrate and oxide layer. Regarding biomimetic apatite formation, the t-ZrO2 particles uniformly spread were of considerable importance in triggering the nucleation and growth of biomimetic apatite on the surface of the oxide layer immersed in a simulated body fluid solution. The growth and proliferation rates of the osteoblasts (MC3T3-E1) cultured on the oxide layer with t-ZrO2 particles were higher than that without t-ZrO2 particles due to the higher roughness providing the better sites for the filopodia extension and interlocking.

Oxide Layer Modification of Mg-Al Alloy Coated by Plasma Electrolytic Oxidation Using Zirconia Particles

The paper reported the effect of zirconia incorporation on the oxide layer modification of the valve metal such as magnesium coated by plasma electrolytic oxidation (PEO). To incorporate zirconia particles into the oxide layer, PEO coatings were carried out under AC condition in electrolytes containing zirconia powder. After PEO coatings, structure observation revealed that a number of zirconia particles were distributed uniformly throughout the oxide layer while the size and distribution of pores remained unchanged as compared to the results coated by PEO without zirconia. It was found that fine zirconia particles incorporated into the oxide layers played an important role in enhancing the anti-corrosion properties of bare metal.