Phase transformations and electrochemical characterizations of electrodeposited amorphous Fe-W coatings

Iron-tungsten with satisfactory corrosion properties is a promising alloy to replace hard chromium. In this work, Fe-W amorphous coatings were prepared by electrodepositing from an aqueous solution and a subsequent heat treatment at 400 degrees C, 500 degrees C, 600 degrees C, 700 degrees C and 800 degrees C, respectively. Corrosion behavior of the coatings deposited on copper substrates was studied using potentiodynamic polarization and impedance spectroscopy techniques in 0.1 mol.L-1 aqueous NaCl solution. As the annealing temperature raises the corrosion resistance of Fe-W coatings increases, and reaches the maximum at 500 degrees C and then shows a converse variation after 500 degrees C. This might relate to the surface reconstruction both on the morphology and the chemical oxidation. (C) 2015 Elsevier B.V. All rights reserved.