The Influence of Temperature and Electroforesis Deposition Green Inhibitor on Bipolar Plate AA5052 in Sulfuric Acid Medium

Abstract

Aluminum alloy 5052 (AA5052) contains Mg (2.2-2.8.8% weight), Cu (0.1% weight), Cr (0.15% weight), Zn (0.1% weight), Si and Fe (0.45% weight) compositions. This material has been widely used as a bipolar plate in Proton exchange Membrane (PEMFC) fuel cells. This material has several advantages such as: lightness, high conductivity, good tensile strength, and flexibility. PEMFC operations produce several by-products, such as water and heat. Generally, the operation of PEMFC is around 333-353 K and the environment is acidic. In this condition the bipolar plate AA5052 will easily experience rust, thus lowering the performance of the PEMFC. In this study, 0.5 g/L Arabic Gum (AG) used as a green inhibitor and coated onto the AA5052 surface through electrophoretic deposition (EPD). The corrosion test was performed in 0.5 M H2SO4 (pH 2) solution under the simulated PEMFC condition. Scanning electron microscopy (SEM) was used to analyze the morphology, and potentiodynamic polarization to determine the corrosion rate. Result shows that AG coating can reduce 60% the corrosion rate of AA5052 after immersed in 0.5 M H2SO4 for 168 h. The effect of temperature on the inhibition efficiency reached 14.4% under the same condition. AG can be used as a green inhibitor to reduce the corrosion rate of AA5052 bipolar plate.

Effect of Chitosan on the Corrosion Inhibition for Aluminium Alloy in H2SO4 Medium

“…The EPD process was performed at room temperature with AA5052 as the cathode. The EPD process was conducted for 10, 20, and 30 min with an applied voltage of 20 V. Corrosion rate tests included weight loss analysis of AA5052 coated and uncoated chitosan; these were immersed in 0.5 M H 2 SO 4 for 72, 120, and 168 h at room temperature [19][20][21][22][23].…”

“…Based on Table 4, the corrosion potential values (Ecorr) of metal AA5052 coated with the inhibitor layer were always below the corrosion potential value (Ecorr) of metal AA5052 uncoated with an inhibitor layer; chitosan is a mixed inhibitor with dominant protection in the cathodic area [19][20][21]. A decrease in the value of corrosion potential (Ecorr) at a temperature range of 298 K to 333 K indicated an increase in the anodic reaction, in which the oxidation process took place faster.…”

“…Variations in the thickness of the inhibitor layer can be caused by the length of time the potential EPD is used, the concentration of the suspension (coating) used and the electrical conductivity of the solvent used. The EPD process will usually produce a layer thickness ranging from 0.1 μm to approximately 100 μm [18][19][20].…”