Corrosion Behavior of 45 Steel in Molten Nitrate Salts with 3wt% Impurities at 773.15K

In this paper, the corrosion behavior of 45 steel in molten HitecXL salt (1# salt) and HitecXL salt with 3wt%MgCl2 (2# salt) at 773.15K is studied by gravimetric methods. The cross section characteristics, the elements distribution features and corrosion products of the samples after corrosion are analyzed by SEM, XRD and EDS. The results show that the corrosion kinetics curves of 45 steel for 84 h in 1# and 2# salt all obey the linear law. The cross section morphology show that the corrosion layer depths of the samples are about 10μm and 25μ, respectively. Cl^- react with O₂ dissolved in the molten salts to form Cl₂.then, Cl₂ can react with Fe or the oxides of Fe to form FeCl₃, which make 45 steel have bigger corrosion rate in 1# salt. The corrosion mechanisms of 45 steel in two kinds of salt are the loss of Fe.