Although boronizing is known as a useful surface-improving treatment for spheroidal graphite cast iron (SG iron) , the corrosion resistance of boronized SG iron has seldom been reported. Graphite configuration, however, seems to affect on the morphology of boride layer and the corrosion resistance in SG iron. Anodic polarization measurements are performed on 0.01NHCl solution to study the effect of boronizing on the corrosion resistance of SG irons with identical chemical composition and different graphite nodule sizes or counts. The results show that : (1) Boronizing improves corrosion resisitance in SG iron, and FeB is more effective than Fe2B. (2) Increasing the graphite nodule size decreases the corrosion resistance of boronized specimens, as well as untreated and oil-quenched specimens.
