A Study of Corrosion Behaviour of Chromium Alloyed Ductile Iron in Cassava Juice

Abstract

This paper investigated the efficiency of chromium, an alloying element in duc-tile cast iron, in inhibiting corrosion in cassava juice. Samples were prepared by adding chromium (0.5, 1.0, 1.5 and 2.0 wt.%) respectively to ductile cast iron and investigating the effect of increasing the chromium content on the corrosion of the ductile iron in cassava juice. Prepared samples were immersed in fresh water and cassava juice for a period of thirty two days (32) days and weight loss measured after every four days. A control sample was also produced and tested. Results showed that the control sample had the highest corrosion rate in both fresh water and cassava juice media. The sample containing the highest weight percent of chromium was found to resist corrosion the most, probably due to the increased content of chromium which resulted in enhanced formation of chromium oxide passive layer coupled with the reduction of the concentration of the cassava juice as exposure time increased. The decrease in corrosion rate of the alloys reflected on the micrographs as the micrographs of the alloyed samples showed fewer cavities on their surfaces when compared with the control sample where corrosion was severe. Effective protection of the ductile iron was observed as the chromiun content increases.