Corrosion and Protection of Ni-based Alloy Heating Tube

The corrosion performance of Ni-based alloy Incoloy800 and Incoloy840 was studied by oxalic acid etch test, potentiodynamic polarization test, galvanic corrosion experiment and SEM. The influence of processing on the corrosion resistance of these two alloys was also discussed. The results showed that alloy Incoloy800 and the heating tube made of it had better intergranular corrosion resistance compared with Incoloy840 and the tube made of it. Pitting potential of Incoloy840 decreased significantly and Incoloy800 almost showed little change in pitting potential after processing. The galvanic current density of Incoloy800 heating tube/Mg was higher than that of Incoloy840 heating tube/Mg, indicating that Incoloy800 accelerated the corrosion rate of Mg anode more remarkably.