Carbonitriding “Pack Cyaniding” of Ductile Irons

Abstract

In this paper, ductile iron was produced using a rotary furnace. The microstructures of the ductile iron (with and without cyanided coatings) were then characterized using optical microscopy, scanning electron microscopy (SEM) and energy diffraction X-ray spectroscopy (EDS). The surfaces of the ductile iron were then subjected to high temperature carbonitriding using a pack cementation process in which carbon and nitrogen were diffused into the ductile iron from powder mixtures consisting of ground cassava leaves and barium carbonate (BaCO3) energizers. The wear behavior of the coated and uncoated ductile iron was studied using the pin-on-disk method. The wear mechanisms were also elucidated using a combination of SEM and EDS. The mechanisms of wear were also studied using nanoscratch experiments. The resulting wear rates are then compared with those from micron-scale wear tracks obtained from pin-on-disk experiments. The implications of the results are then discussed for the design of wear resistant ductile irons.