Investigation of the inhibition effect of the environmentally friendly inhibitor sodium alginate on magnesium alloy in sodium chloride solution

Abstract

The corrosion inhibition and adsorption behavior of sodium alginate on AZ31 magnesium alloy in 3.5 wt% sodium chloride solution is investigated. The results show that sodium alginate can effectively inhibit the corrosion of AZ31 magnesium alloy. With increasing sodium alginate concentration, the inhibition efficiency initially increases and then decreases. It reaches a maximum of 90.00% at a sodium alginate concentration of 500 ppm. The inhibition is due to adsorption of sodium alginate on the bare magnesium alloy surface, where it mixes with magnesium hydroxide to form a more continuous and compact film, which retards the corrosion of the alloy.

Tackling Mg alloy corrosion by natural polymer coatings—A review

“…Hydrogen evolution tests indicated a similar trend. Recently, Dang et al . used sodium alginate as corrosion inhibitor on top of AZ31 alloys.…”

“…Hydrogen evolution tests indicated a similar trend. Recently, Dang et al 45 used sodium alginate as corrosion inhibitor on top of AZ31 alloys. Electrochemical measurements at different concentrations showed the maximum charge transfer inhibition efficiency to be 86.62% at 500 ppm of alginate in 3.5 wt % sodium chloride solution.…”

“…Electrochemical measurements at different concentrations showed the maximum charge transfer inhibition efficiency to be 86.62% at 500 ppm of alginate in 3.5 wt % sodium chloride solution. The authors proposed that different immersion times investigated were responsible for the different corrosion protection ability of the coatings. Indeed, alginate coating did not fill all cracks and pores in the magnesium hydroxide layer, therefore efficiency values of 100% were not reached.…”

“…Considering the available information in literature, it can be stated that sodium alginate is an effective corrosion inhibitor, slowing down the degradation rate of Mg/Mg alloys. Through hydrophilic and lipophilic groups alginate adsorbs on the surface of magnesium, generating a composite film, which impedes the corrosion medium to come in direct contact with the surface . In a recent study, Gao et al .…”

In situ surface film evolution during Mg aqueous corrosion in presence of selected carboxylates

“…Corrosion of Mg and its alloys has been extensively studied in recent decades due to their potential application in numerous areas from engineering materials to bio-implants and batteries [1][2][3][4][5][6][7][8][9][10]. Particularly, numerous new inhibitors for Mg corrosion are reported regularly [11][12][13][14][15][16][17][18]. In a recent review [11] Mg inhibitors were classified by the mechanism of their action (anodic, cathodic or mixed type) and by the type of their interaction with the substrate (adsorption/precipitation type).…”