Characterisation of Cassava Cyanide on Heat Treated Ductile Cast Iron

Abstract

The present study explored the feasibility of using cassava leaves (CL) cyanide for surface strengthening of ductile cast irons through heat treatment. Dried cassava leaves were pulverized and sieved to 500 µm particle size, the pulverised mass was mixed with BaCl2 (energizer) at a ratio of 4:1 by weight. Standard ductile iron samples were produced using sand casting technique and the samples were heat treated at temperatures ranging from 750 to 900°C in steps of 50°C for the period of 3—5 hours. Characterization of the cyanided ductile iron was carried out using JEOL 7600F Field Emission Scanning Electron Microscope (SEM), Oxford X-Man (EDS), PANALYTICAL Empyrian X-Ray Diffractometer (XRD) and LECO ASTM E384 hardness tester. All analyses are carried out to ascertaining the formation of a case within the microstructure and phase formation owing to the heat treatment. The results revealed graphite nodules surrounded by ferritic-pearlitic matrix for the as-cast samples while the Pack Cyanided Cassava Leaves (PCCL) samples revealed dark structures (visible diffusion zone) at the edges of the samples containing carbides and appreciable amount of nitrides precipitation in the matrix (case) while the center reveals a ferritic/pearlite matrix (core).