Comparative erosion–corrosion and electrochemical studies of Ni austenitic cast iron in acidic slurry medium

Abstract

Laboratory experiments were conducted on the erosion–corrosion resistance of four groups of austenitic cast iron with different nickel contents under different acidic slurry conditions. The experiments involved measuring weight loss, examining corrosion morphology as well as X-ray diffraction analysis and electrochemical techniques. While the results showed little erosion–corrosion in a base sand particles environment, erosion–corrosion increased progressively with additions of HCl solution. With the presence of H⁺, intergranular corrosion and pitting attacks were centred at the boundaries of graphite flakes and alloy carbides. The electrochemical tests showed that the enrichment of nickel and copper in low Ni austenite cast iron can increase the corrosion potential to some extent. As a result, the low Ni cast iron in which Ni content is 8·36 wt-%, and Mn content is 6·57 wt-% exhibited better corrosion resistance than other low Ni cast irons and demonstrated comparable performance with high Ni austenite cast iron.