Hot dip aluminizing (HDA) is widely used in industry for improving corrosion resistance of material. The formation of intermetallic compound layers during the contact between dissimilar materials at high temperature is common phenomenon. Generally, intermetallic compound layers of Fe 2 Al 5 and FeAl 3 are formed at the Al alloy and Fe substrate interface. In case of cast iron, high contact angle of graphite existed in the matrix inhibits the formation of intermetallic compound layer, which carry with it the disadvantage of a reduced reaction area and mechanical properties. In present work, the process for the removal of graphite existed on the surface of specimen has been investigated. And also HDA was proceeded at 800 o C for 3 minutes in aluminum alloy melt. The efficiency of graphite removal was increased with the reduction of particle size in sanding process. Graphite appears to be present both in the region of melting followed by re-solidification and in the intermetallic compound layer, which could be attributed to the fact that the surface of cast iron is melted down by the formation of low melting point phase with the diffusion of Al and Si to the cast iron. Intermetallic compound layer consisted of Fe(Al,Si) 3 and Fe 2 Al 5 Si, the layer formed at cast iron side contained lower amount of Si.

Fusion bonding of cast iron and Al alloy is an effective way to improve the properties such as low inertia, high efficiency and corrosion resistance in machinery parts. In case of fusion bonding, intermetallic compound layers are formed at the interface between cast iron and Al alloy interface. It is important to control the intermetallic compound layers for improving bonding strength. The formation behavior of intermetallic compound layer by heat treatment has been investigated. Heat treatment was performed at temperature from 600 o C to 800 o C with 100 o C interval for an hour to investigate the phase transformation during heat treatment. Heat treated specimens were analyzed by using FE-SEM, EPMA and EDS. The EPMA/WDS results revealed that various phases were formed at the interface, which exhibited 4 distinct intermetallic compound layers such as τ 6 -Al 4.5 FeSi, τ 2 -Al 3 FeSi, τ 11 -Al 5 Fe 2 Si and η-Al 5 Fe 2 . Also, fine precipitation of τ 1 -Al 2 Fe 3 Si 3 phase was formed between τ 11 and η layer. The phase fraction in intermetallic compound layer was changed by heat treatment temperature. At 600 o C, intermetallic compound layer of τ 6 phase was mainly formed with increasing heat treatment time. With increasing heat treatment temperature to 800 o C, however, τ 2 phase was mainly distributed in intermetallic compound layer. τ 1 phase was remarkably decreased with increasing heat treatment time and temperature.