Corrosion resistance of steel-based surface alloyed materials fabricated with Fe-based metamorphic powders by high-energy electron beam irradiation

Abstract

Corrosion resistance of steel-based surface alloyed materials fabricated with Fe-based metamorphic powders by high-energy electron beam irradiation was investigated in this study. Two kinds of metamorphic powders were deposited on a plain carbon steel substrate, and then electron beam was irradiated on these powders to fabricate surface alloyed materials. In the surface alloyed layers, 48-64 vol.% of Cr2B or Cr1.65Fe0.35B0.96 borides were precipitated in the Cr0.19Fe0.7Ni0.11 or martensite matrix, and thus their hardness was two to three times higher than that of the steel substrate. The overall corrosion resistance of the surface alloyed materials was better than that of an STS304 stainless steel or coatings fabricated by high-velocity oxygen fuel spraying of same powders. The observation results of pits formed on the corroded surface revealed that Cr0.19Fe0.7Ni0.11 and martensite phases of the surface alloyed materials and coatings was selectively corroded, while borides were retained inside pits, by forming a galvanic coupling. These findings suggested that the fabricated surface alloyed materials presented good application possibilities as excellent wear- and corrosion-resistant materials. (c) 2006 Elsevier B.V. All rights reserved.