Cerium citrate as ecologically friendly corrosion inhibitor for AA7075 alloy

Abstract

The corrosion behaviour of high-strength AA7075 aluminium alloy in NaCl solution, without and in the presence of environmentally friendly corrosion inhibitors (Ce-chloride and Ce-citrate) in low concentrations (<0.5 mM), was analysed. The degree of precipitation of the solid solution of AA7075 alloy was determined by measuring the electrical conductivity, while the surface morphology and appearance of intermetallic compounds before and after corrosion testing were analysed by SEM/EDS method. The general corrosion resistance of the tested alloy in NaCl solution and the degree of the inhibitory effect of the corrosion inhibitors were determined on the basis of electrochemical impedance spectroscopy and polarization measurements, while resistance to pit formation on the bases of E pit . AA7075 alloy showed high resistance to general corrosion in the presence of both tested inhibitors, while resistance to pit formation was significantly higher in the presence of Ce-citrate (concentration 0.5 mM). Also, Ce-citrate present in NaCl solution at lower concentrations provides satisfactory resistance of AA7075 alloy to general and pitting corrosion. A mechanism of protective action of Ce-citrate inhibitor has been proposed.

Analysis of inhibitory properties of Ce‐citrate as a green corrosion inhibitor of low alloy steel in neutral chloride solution

“…The authors of this paper recently analyzed the inhibitory properties of Ce‐citrate in neutral NaCl solution on aluminum alloy AA7075. [ 34 ] Ce‐citrate has shown very effective corrosion inhibitory properties on this aluminum alloy. However, due to the presence of oxide passive film (Al 2 O 3 ) and intermetallic inclusions of different compositions, and so on, the corrosion and electrochemical behavior of the aluminum alloys differ significantly from the behavior of the steel.…”

Analysis of the Ce(III) chloride, Ce(III) nitrate, and Ce(III) propionate as corrosion inhibitor of the aluminum alloys in NaCl solution

“…[22][23][24][25] Also, the various cerium salts were tested, and it was found that Ce acetate has the best protective ability on the 7xxx series aluminum alloy. [24] Other cerium salts were also tested, such as citrates, [26] phosphates, [27] sulfates, [24,28,29] perchlorates, [24] and nitrates. [28,30,31] The Ce acetate inhibitory effect of the 7xxx series aluminum alloy has recently been investigated in detail.…”

Inhibitory effect of cysteine and lanthanides on AA7075‐T6 in neutral NaCl solution

“…In the following period, various inorganic cerium salts were tested to improve the inhibitory effect of cerium, such as nitrates, [9][10][11] perchlorates, [12] and sulfates. [12,13] Also organic cerium salts, such as diphenyl phosphate, [14] formate, [15] acetate, [13,[15][16][17] citrate, [18] and propionate [15] were analyzed.…”