CORROSION BEHAVIOUR OF AZ31 ALLOY IN AN ALKALINE ENVIRONMENT OF 0.1 M NACL IN THE PRESENCE OF LIGNITIC HUMIC ACID

Abstract

Magnesium alloys are characterized by high corrosion rates. This undesirable phenomenon can be slowed down by corrosion inhibitors. Particularly environmentally friendly molecules are in the spotlight. A possible candidate for a green inhibitor may be humic acid isolated from lignite. In this work, the corrosion behavior of AZ31 was investigated in 0.1 M NaCl with and without humic acid at pH 9. Surface analysis was performed using a scanning electron microscope (SEM) with an energy dispersive X-ray spectroscope (EDS) and Fourier--transform infrared (FTIR) spectroscopy. Corrosion behavior was investigated using potentiodynamic polarization (PDP) measurements. The results showed that lignitic humic acid accelerates corrosion in 0.1 M NaCl at pH 9 and this effect was concentration dependent.Magnesium alloys are characterized by high corrosion rates. This undesirable phenomenon can be slowed down by corrosion inhibitors. Particularly environmentally friendly molecules are in the spotlight. A possible candidate for a green inhibitor may be humic acid isolated from lignite. In this work, the corrosion behavior of AZ31 was investigated in 0.1 M NaCl with and without humic acid at pH 9. Surface analysis was performed using a scanning electron microscope (SEM) with an energy dispersive X-ray spectroscope (EDS) and Fourier--transform infrared (FTIR) spectroscopy. Corrosion behavior was investigated using potentiodynamic polarization (PDP) measurements. The results showed that lignitic humic acid accelerates corrosion in 0.1 M NaCl at pH 9 and this effect was concentration dependent.