Influences of Si on corrosion of Fe–B alloy in liquid zinc

Abstract

Influences of silicon content on the microstructure and corrosion resistance of a Fe–2·5 wt-%B alloy have been investigated by using scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy. Si can change the microstructure from hypereutectic to eutectic and furthermore, enhance the corrosion resistance of the alloy in molten zinc. The high corrosion resistance of the alloy was mainly attributed to the eutectic phase increase and solubility of Si in α phase enhancement. The corrosion of these alloys in liquid zinc was controlled by the diffusion mechanism. The reaction products are FeZn_6·67, Fe₅SiB₂ and FeSi. The reaction layer further prevents the diffusion of zinc atoms into the base material and delays the reaction between the substrate and the molten zinc efficiently.