Investigating TiO_(2)-HA-PCL hybrid coating as an efficient corrosion resistant barrier of ZM21 Mg alloy

摘要

Surface modification for improving corrosion resistance of Mg alloys is highly demanded for degradable orthopedic and cardiovascular devices.The research reports the design and development of TiO_(2)–HA composite and novel TiO_(2)–HA–PCL hybrid coating belonging to the unique class of inorganic organic hybrid with striking features that are explored for the first time in the corrosion resistance of Mg alloys.Sol–gel dip coating combined with non-solvent induced phase separation is used to create the hybrid coating.TiO_(2)–HA–PCL hybrid coating introduces strong hydrogen bonding between TiO_(2)–HA inorganic matrix and PCL organic layer in addition to the Vander wall electrostatic interaction of the later with the Mg substrate which in turn enhance adhesion strength to about 1.5 times of TiO_(2)–HA coating.The corrosion potentials for TiO_(2)–HA–PCL and TiO_(2)–HA were found to be-0.407 V and-1.017 V(vs Ag/Ag Cl),respectively.The current densities of TiO_(2)–HA–PCL and TiO_(2)–HA were found to be 7.31×10^(-8)A/cm^(2)and 4.03×10^(-4)A/cm^(2)respectively.The corrosion resistance of coatings was confirmed by immersion testing by weight loss,pH changes and H_(2)evolution measurements at interval of 7 days till 28 days.The present TiO_(2)–HA–PCL coating in comparison to TiO_(2)–HA coating demonstrate nearly 6%less weight loss.The outcome of the present work was compared with the similar coatings in recent past.The work done ingresses enhancing the corrosion resistance of Mg alloys,which fulfill the dreams of future degradable orthopedic and cardiovascular devices.