In Situ Construction of Fluorescent and Corrosion Resistant Coating by Plasma Electrolytic Oxidation on Magnesium Alloy

In this paper, Yb3+/Er3+ codoped hydroxyapatite (HAp) nanoparticles were prepared by the hydrothermal method. And the upconversion fluorescent coating based on HAp:Yb3+/Er3+ on the magnesium alloy surface was successfully synthesized by the plasma electrolytic oxidation method. The influence of composition of HAp:Yb3+/Er3+ on the morphology, phase structure, upconversion fluorescent and corrosion resistance of the coatings were systematically investigated by scanning electron microscopy, energy-dispersive spectrometry, x-ray diffraction, upconversion fluorimeter and potentiodynamic polarization. Visible upconversion emissions are observed on the PEO@HAp:Er3+/Yb3+ coating under optical pumping at 980 nm. Compared with the original magnesium alloy, the upconversion fluorescence coatings can significantly reduce the corrosion rate of the matrix in Hank's solution. This upconversion fluorescent coating maybe provides a feasibility and promising prospect for revealing the material tissue interrelation and labeling the surface states of implanted material.