Compositional design of low carbon sulphuric acid dewpoint corrosion resistant steel and corresponding anticorrosive mechanism

Abstract

The optimal contents of C, S, Cu and Sb in a new low alloy steel for the purpose of improving the sulphuric acid dewpoint corrosion resistance were investigated by weight loss and potentiodynamic polarisation in 50 wt-%H 2 SO 4 at 70uC. The optimal elemental contents of C, S, Cu and Sb in the low carbon sulphuric acid dewpoint corrosion resistant steel (SADPS) are 0?09, 0?016, 0?3 and 0?09 respectively. The corrosive products of Fe 2 (SO 4 ) 3 and FeSO 4 were found on the surface of plain low carbon steel while corrosive products of (Cu,Fe)SO 4 , FeSbO 4 , FeSb 2 O 4 , CuSbO 4 and CuO were found on the surface of SADPS. Potentiodynamic polarisation test also revealed that the higher corrosion resistance of SADPS was due to inhibition of the cathodic reaction due to surface enrichment by the alloying elements.

Corrosion behaviour of experimental copper–antimony–molybdenum carbon steels in industrial and marine atmospheres and in a sulphuric acid aqueous solution

“…Antimony and aluminium were identified in all corrosion product layers. Wu et al [21] also found corrosive products containing antimony, such as FeSbO 4 , FeSb 2 O 4 , CuSbO 4 , on the surface of a low carbon SADPS. They also found (Cu,Fe)SO 4 and CuO [21] on the steel surface.…”

“…Le et al [23] reported that the addition of 0.10 wt-% antimony in copper-bearing steel stimulated the development of high corrosion, inhibiting copper-containing compounds which further inhibited the anodic and cathodic reactions. The effect of antimony seems to be contributing to enhance the protective characteristic of the rust layer, catalysing the formation of copper compounds or producing antimony oxides [21,23].…”

“…Literature on the effect of antimony on corrosion resistance of low alloyed steels is scarce. Sb-containing steels were developed specifically for acid corrosion resistance and work by increasing the overpotential for hydrogen evolution [21]. Wu et al [21] developed a new low alloyed steel, a low carbon sulphuric acid dewpoint corrosion resistant steel (SADPS), for the purpose of improving the sulphuric acid dewpoint corrosion resistance.…”

“…Sb-containing steels were developed specifically for acid corrosion resistance and work by increasing the overpotential for hydrogen evolution [21]. Wu et al [21] developed a new low alloyed steel, a low carbon sulphuric acid dewpoint corrosion resistant steel (SADPS), for the purpose of improving the sulphuric acid dewpoint corrosion resistance. Potentiodynamic polarisation test in 50 wt-% H 2 SO 4 at 70°C revealed that the higher corrosion resistance of SADPS was due to inhibition of the cathodic reaction due to surface enrichment by the alloying elements [21].…”

“…Wu et al [21] developed a new low alloyed steel, a low carbon sulphuric acid dewpoint corrosion resistant steel (SADPS), for the purpose of improving the sulphuric acid dewpoint corrosion resistance. Potentiodynamic polarisation test in 50 wt-% H 2 SO 4 at 70°C revealed that the higher corrosion resistance of SADPS was due to inhibition of the cathodic reaction due to surface enrichment by the alloying elements [21]. Cornet et al [22] studied the effect of the addition of antimony or tin to austenite nickel-chromium-based alloys on intergranular hydrogen embrittlement.…”