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Role of Electric Pulse Duty and Frequency on Properties of Micro-Arc Oxidized Titania Films Developed on Ti-6Al-4V
Abstract:
The present work is mainly focussed on studying the effect of electric pulse frequency and duty cycle on the structural, morphological and corrosion characteristics of micro arc oxidation (MAO) films developed for a fixed oxidation time of 2.5 min on Ti-6Al-4V biomedical implant material. For this purpose, the titania films are decisively developed under four different conditions arising from two levels of pulse duty cycle (10% and 75%) and frequencies (500 Hz and 1500 Hz). A phosphate based electrolyte system is employed for developing the titania films. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results demonstrated that though all the titania films are developed for the same oxidation time of 2.5 min, the rate of anatase to rutile phase transformation, the crystallite growth, the size and distribution of surface pores and film thickness of the titania film are strongly influenced by the electric pulse frequency and duty cycle. The potentiodynamic polarization (PDP) tests conducted under simulated body fluid (SBF) conditions (37 °C and 7.4 pH) showed that all the titania films could significantly improve the corrosion resistance of Ti-6Al-4V compared to that of the untreated alloy. Of all the titania films developed for the same oxidation time of 2.5 min, the one treated with 1500 Hz frequency and 75% duty cycle exhibited better corrosion resistance than those of the other films and the untreated Ti-6Al-4V implant material.
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Pages:
688-692
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Online since:
July 2013
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