Galvanic Corrosion in 3.5 wt. % NaCl Solutions of Magnesium alloy AZ31 Coupled with Ni After Different Bonding Periods of Time

Journal Article

Alhazaa, Abdulaziz . 2015

• Publication Online URL: Galvanic Corrosion in 3.5 wt. % NaCl Solutions of Magnesium alloy AZ31 Coupled with Ni After Different Bonding Periods of Time
• Magazine \ Newspaper: INTERNATIONAL JOURNAL OF ELECTROCHEMICAL SCIENCE
• Issue Number: 7
• Volume Number: 10
• Pages: 5420-5433

Publication Abstract

The magnesium alloy AZ31(96Mg-3Al-1Zn alloy) was coupled with nickel using transient liquid phase bonding method at 520 o C for different periods of time varied from 5 min to 40 min. The corrosion behavior of the Mg alloy AZ31 without and with Ni coupled within it in 3.5 wt.% sodium chloride solution was reported using cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS). The study was complemented by scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysess. CPP experiments indicated that bonding the Mg alloy AZ31 with Ni increases its corrosion through increasing the values of corrosion current density (j Corr) and corrosion rate (R Corr) as well as decreasing their polarization resistance (Rp). Elongating the bonding time from 5 min up to 40 min led to further increases in the corrosion of AZ31. The EIS measurements showed that bonding the magnesium alloy with Ni and the increase of bonding time decreases the diameter of the obtained semicircle obtained by Nyquist plots, decreases the values of the impedance of the interface and the maximum degree of phase angle obtained by Bode plots. SEM/EDX investigations confirmed that bonding the Mg alloy with Ni increases the dissolution of the alloy via galvanic corrosion, which was found to increase with increasing the time of bonding.