Corrosion resistant Cr-coating on mild steel by powder roll bonding

Chromium powder coating on mild steel was developed by roll-bonding followed by annealing at 1200 degrees C for different duration in hydrogen atmosphere to promote diffusion bonding and finally furnace cooling. All the coated samples were characterised using scanning electron microscopy, electron probe micro analyser, bend test and potentiodynamic polarisation test in 0.2 N H2SO4 solution. Diffusion layer thickness was in the range of 170-250 mu m depending on the annealing time, and the Cr content reached up to 13 wt% in the diffusion layer. Diffusion layer exhibited high ductility and adhesion, since no crack was observed even after 180 degrees bending. The chromium coated mild steels showed comparable stable passivity and corrosion rates in 0.2 N H2SO4 solution as observed in a 304 stainless steel. The corrosion rate decreased from 5.51 mm/y for the uncoated mild steel to 0.2-1.0 mm/y for the coated mild steel sample. (C) 2016 Elsevier B.V. All rights reserved.