Research on the Alkali Corrosion Resistance Mechanism of Ni-Cr-Cu Alloy Cast Iron

In allusion to facility corrosion problem in caustic soda industry five types of ni-Cr-cu alloy cast irons were developed. The corrosion rates of ni-Cr-cu alloy cast irons in hot concentrated alkali solution were measured by using self-made dynamic corrosion experiment equipment; the microstructures and surface corrosion morphology of alloy cast irons were observed by means of the optical microscope and SEM; the composition was analyzed using XES. Corrosion resistance mechanism were discussed detailedly. the experimental results showed that ni-Cr-cu cast iron was uniform corrosion macroscopically in the dense caustic soda at high temperature and there was ni, cu enrichment microcosmically. The Ni and Cu enriched in the matrix , which increase in local electrode voltage of the matrix,are advantageous to the improvement of caustic corrosion resistances of that zone. The higher Ni content,the better alkali corrosion resistance performance with high temperature.