Electrochemical Corrosion Behavior of Ti-6Al-4V Alloy Using Akermanite As a Bioceramic Coating

Abstract

In recent years, ceramic material Akermanite (Ca2­Mg­Si2O7) by the ability to connective and link with the hard tissue of the body, In the recovery, treatment and orthopedics of bone and implants coated body has been considered. The purpose of this research was manufacture, preparation and evaluation and characterized of Akermanite nanoparticles and applied this coating on titanium alloy substrate (Ti-6Al-4V) with sol-gel method. Akermanite nanoparticles were prepared by sol-gel method and its structure was determined by X-ray diffraction test. To study the morphology and particle size of Akermanite, transmission electron microscopy (TEM) was used. The morphology and microstructure surface of coating were evaluated by scanning electron microscopy (SEM). Bioactivity of coating was evaluated in body simulation solutions (SBF). Polarization and electrochemical impedance electrochemical test in two different physiological solution was performed in order to compare the corrosion behavior of coated and uncoated titanium samples. Transmission electron microscopy was confirmed powder sizes below 100­nm. According to the Tofel and Linear polarization tests, in the presence of coating in physiological solution compared to Ringer's solution, corrosion current density decreased and corrosion potential shifted to the more noble values and corrosion resistance of the alloy increased. Based on the results obtained by the impedance test, in the presence of Akermanite coating in physiological solution, charge transfer resistance increased and double-layer capacity decreased, which shows improvement in corrosion resistance. According to the corrosion tests, Akermanite coating created on the surface of titanium alloy, has created higher corrosion resistance in physiological solution, compared to Ringer's solution. According to the results of bioactivity test and scanning electron microscopy (SEM), hydroxyapatite is formed on the surface of alloy. The results showed that Akermanite bioceramic coating applied by the sol-gel method, reduced the release of metal ions and improve the biocompatibility of metal implants and also, promote their potential ability to the growth of bone and connective with it.