Fabrication and electrochemical behavior of plain carbon Steel-B4C-W Composite in 3.5 wt % NaCl solution

Abstract

In this work, the electrochemical behavior of metal-matrix composite plain carbon steel-boron carbide (B4C)-tungsten (W) was studied in 3.5 wt % NaCl solution. Boron carbide is well known for its high hardness resistance. Elemental tungsten resists attack by oxygen, acids, and alkalis. The composite was locally produced as weld band on carbon steel by means of gas tungsten arc welding process and using nickel (Ni) as wetting agent. Samples from weld band, heat-affected zone and base metal regions were extracted precisely and electrochemical techniques including electrochemical impedance spectroscopy, potentiodynamic polarization in combination with scanning electron microcopy; energy dispersive spectrometry, X-Ray electron diffraction and micro-hardness testing were used for characterization. The results showed that hardness value of composite increased significantly to 782 HV. However the corrosion resistance of composite region after 2 h of immersion in 3.5 wt % NaCl solution was slightly reduced.