Influence of sodium alginate and chromate on aluminum corrosion in simulated HVDC cooling water

The laws for Al corrosion in acetic acid solutions containing the corrosion inhibitors sodium alginate and Na2CrO4 were studied, and the mechanisms for corrosion protection by the inhibitors were explored with electrochemical determinations of the potentiodynamic polarization curves and EIS curves. The Al corrosion inhibition rates were calculated for the two corrosion inhibitor solutions, and the mechanisms for inhibition of Al corrosion were analyzed. Characterization of the surface morphologies showed that (C6H7NaO6)x and Na2CrO4 both inhibited Al corrosion, but the performance of (C6H7NaO6)x as a diffusion inhibitor was better than that of Na2CrO4 as a surface modification inhibitor, this was because sodium alginate with hydrophobic group had certain adhesion and low electrical conductivity, which could effectively adhere to the Al surface and increase the resistance of microbattery. A comparative study of the inhibition mechanisms for different corrosion in-hibitors provided a theoretical basis for identifying better corrosion inhibitors.