Inhibition Effect of Calcium Tartrate on the Corrosion of Pure Aluminum in an Alkaline Solution

Abstract

The corrosion behavior of aluminum in 1 M potassium hydroxide (KOH) solution with and without calcium tartrate was investigated by means of weight loss measurement, open-circuit potential measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy. Experimental results showed that the corrosion of aluminum was inhibited by the addition of calcium tartrate. At high calcium tartrate concentrations, the anodic and cathodic processes were greatly inhibited. At its low concentration, the effect of the inhibitor on the former was much stronger than that on the latter. This might have been caused by the selective adsorption of the inhibitor on anodic active sites.

Potential of aqueous extract of Hibiscus sabdariffa leaves for inhibiting the corrosion of aluminum in alkaline solutions

“…The low-frequency capacitive loop indicated the growth and dissolution of the surface film [20]. As can be seen in the presence of AEHSL, the Al electrode showed EIS spectra similar to that obtained in the blank solution, only ''amplified'', indicating that the inhibition category under this condition belongs to geometric blocking [20,21]. The equivalent circuit model of the previous systems is shown in Fig.…”

“…5. A similar circuit was suggested for the corrosion behavior of the Al electrode in 1.0 M KOH with and without calcium tartrate [20]. Values of R ct , C dl and IE R % for inhibited and uninhibited systems were estimated and are listed in Table 2.…”

Influences of zinc oxide and an organic additive on the electrochemical behavior of pure aluminum in an alkaline solution

“…The high-frequency loop is caused by the charge transfer resistance in parallel with the double-layer capacitance. The inductive loop may be attributed to the adsorbed intermediate, and the low-frequency loop to the growth and dissolution of the surface film [19,20,23]. The EIS greatly changes when 0.2 M ZnO is added to the electrolyte, and includes a small high-frequency capacitive loop and a Figures 2(b) and (c) that the addition of DE changes the deposition mechanism of zinc, increases the value of the charge transfer resistance, and then improves the deposition of zinc by increasing electrochemical polarization.…”

“…Figure 2(a) gives the EIS of aluminum in 4 M KOH solution, which reflects the processes of aluminum dissolution and hydrogen evolution. This EIS consists of three parts: a high-frequency capacitive loop, a small middle-frequency inductive loop and a lowfrequency capacitive loop [19,20]. The high-frequency loop is caused by the charge transfer resistance in parallel with the double-layer capacitance.…”

“…However, in alkaline electrolytes pure aluminum self-discharges readily by corrosion, resulting in utilization of much less than 100%. With the purpose of improving the behavior of the aluminum anode, two methods are usually used: (1) alloying aluminum with other elements [13][14][15]; (2) modifying the electrolyte by adding inhibitors [15][16][17][18][19][20].…”