Effect of Silicon on Corrosion of Directional Fe-B-Si Alloy in Liquid Zinc

Abstract

The effect of Si on the corrosion of an Fe-B-Si alloy in liquid zinc was investigated. Corrosion tests of Fe-B-Si were conducted in a pure zinc bath (99.99 wt pct Zn). The results indicated that Si in a-Fe phase had a significant effect on the structure and evolution of corrosion interfaces in a directional Fe-B-Si alloy immersed in liquid zinc. Moreover, Si enrichment of the corroded interface induced changes in the mode of element diffusion, thereby affecting the Fe-Zn reaction and the quantity and volume of Fe-Zn compound. The Fe-Zn compound was occluded with the residual Fe 2 B closest to the corrosion interface, this structure could prevent direct contact between the liquid zinc and the alloy, and firm rooting of the compound at the interface. Therefore, Si in a-Fe phase had a significant effect on the corrosion resistance of Fe-B-Si alloy in liquid zinc. At a Si content of 0.318 wt pct, the densest composite corrosion product layer and highest corrosion resistance were obtained.

Effect of Silicon Content on Microstructures and Properties of Directionally Solidified Fe-B Alloy

“…Furthermore, the orientation and size of the hard phases in cast irons can strongly determine the mechanical and wear-reisitant properties of the materials, which may depend on the alloying elements and solidification rates to refine the microstructures [ 30 , 31 ]. Liu et al investigated the effect of Si on the corrosion resistance of DS Fe-B alloy in static liquid zinc, and found that Si improves the corrosion resistance to liquid zinc [ 32 ]. Prince Setia et al found that ~4 wt.% Si addition into stainless steel can give rise to phase transformation from a single-phase austennite to duplex microstructure of ferrite and austenite owing to the ferrite stabilizer effect of Si, e.g., the increase in the activity of carbon and solid solution strengthening of the Si addition [ 27 ].…”