Microstructure of coupled Al/gray cast iron obtained by molding and its effect on mass loss

Abstract

This study aims to consolidate the surface of gray cast iron with aluminum deposition by developing a method that combines the preparation and surface treatment in a single operation. The effect of the wall thickness of the castings on the microstructure of the formed layers was studied, and two thicknesses, 8 mm and 25 mm, were studied. The formation of a continuous and homogeneous rich aluminum layer on the surface of the cast iron was observed. The formed layer is composed of two successive zones identifi ed as two proeutectoid phases FeAl+FeAl/FeAl2 and single-phase FeAl, which signifi cantly increases the surface hardness. Furthermore, this change in surface composition makes it possible to reduce the mass of the immersed samples in a 1 M hydrochloric acid solution during different exposure times (1 to 4 days). Consequently, a clear improvement in the corrosion resistance of the treated layers is highlighted.

Keywords

• gray cast iron
• aluminum; coating
• treatment in the mold
• mass loss