Electrochemical Behaviour of Antimony Modified Carbidic Austempered Ductile Iron (cadi) in Chloride Environment
Year: 2015
Type: article
Abstract: The effects of austempering temperature on the corrosion behaviour of antimony modified carbidic austempered ductile iron were studied.Rod-like samples of diameter 16mm and 200mm were produced by sand casting method.Six different alloys with equivalent carbon of hypereutectic composition (carbon equivalent of 4.44) were used in order to evaluate the effect of antimony contents ranging from 0.096 to 0.48wt.%.The samples were subjected to austenitic temperature of 910 o C and austempered at a temperature of 325 o C on CADI for period of 1 and 3hrs in chloride environment.Microstructural characterization of the material was made with respect to carbide content and composition, besides their stability during the heat treatment.The results show that the microstructures of the as-cast samples were nodular graphite, pearlite and carbides.The heat -treated samples contained graphite nodules, carbides of varying sizes, ausferrite and retained austenite.With increase in antimony content, the size of nodular graphite decreased.At austempering temperature of 300 o C with austempering time of 1hour, sample with 0.288 wt.% of Sb had the least corrosion rate of 2.91E -05 mmpy while at austempering temperature of 325 o C, CADI sample with 0.192 wt.% Sb had the least corrosion rate of 1.59E -05 mmpy.It was observed that electrochemical behaviour of these CADI samples in chloride environment was relatively high, though no graphitic corrosion was observed, the corrosion rate of the samples varied with antimony content, at chosen austempering temperatures and times.Therefore, Sb presence in CADI did not deteriorate the corrosion resistance of the CADI, rather there was improvement in resistance.
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W3083172329