Formation Behavior of an Intermetallic Compound Layer during the Hot Dip Aluminizing of Cast Iron

Abstract

Hot dip aluminizing (HDA) is an effective way to improve the high temperature corrosion resistance and scaling resistance of ferrous materials. The formation of intermetallic compound layers between the two materials is a dominant factor in determining the properties of hot dip aluminized steel. The formation behavior of the intermetallic compound layer between a Si alloyed Al melt and cast iron has been investigated.
The thickness of the intermetallic compound layer was significantly reduced as a result of the increased carbon content of the cast iron matrix. The thickness of the intermetallic compound layer formed in the Al–Si–Fe three-component alloy system remains constant in the early stage of the reaction, and it becomes increasingly rough with increased reaction time. The increased roughness could be attributed to the increased Fe concentration in the Al–Si melt near the cast iron surface, which is a result of the increased inter-diffusion of Al, Si and Fe atoms with increased reaction time by which the formation, melting and spallation of the intermetallic compound layer is enhanced.