The inhibitive effect of magnetic fields on mild steel corrosion in acidic media

Abstract

The inhibitive effect of applied magnetic fields on the corrosion of mild steel in 1.0M HCl and 0.5M H2SO4 acid solutions has been investigated at room temperature by using the gravimetric technique. A locally made electromagnet with variable outputs and powered by a direct current source voltage provided the magnetic fields. In a typical experiment, the applied magnetic field was applied perpendicularly onto the surface of a mild steel coupon immersed completely in a chosen acid solution for an exposure time of two hours. It was observed that the corrosion rates of mild steel determined for each case of 1.0M HCl and 0.5M H2SO4 test solutions decrease as the applied magnetic field increases. This indicates that the presence of the applied magnetic field inhibits the corrosion of the mild steel in the test solutions. Results also show that the protection efficiency of the magnetic field increases as the applied magnetic field increases. More specifically, as the magnetic field was increased from 118.2 - 764.3mG [or 0.01182 - 0.07643 mT], the protection efficiency increased from 36.34 - 62.67% for mild steel in 1.0M HCl acid solution, while for mild steel in 0.5M H2SO4 acid solution, the protection efficiency increased from 12.68 - 46.88%. It was demonstrated that the observed inhibitive effect of the magnetic fields can be attributed partly to the phenomenon of transverse magnetoresistance and partly to the effect of the magnetic fields on the mass transport properties of the constituent ions in the electrochemical system