Improvement in the pitting resistance of Inconel-600 by nitrogen ions implantation

Abstract

The surface of Ni-Cr-Fe (Inconel-600) alloy was modified by implanting 500 keV nitrogen ions at room temperature using pelletron accelerator to dose of 1.87 x 10(14) ions/cm(2). X-ray diffraction analysis of the ions implanted samples indicated the formation of Cr2N phase. Electrochemical testing of Inconel-600 alloy before and after the ions implantation was conducted using potentiodynamic tafel scan, potentiodynamic anodic polarization and electrochemical impedance spectroscopy techniques in an acidic saline solution. The higher anodic polarization slope (beta(a)), low cathodic polarization slope (beta(c)) and decrease in corrosion current density after ions implantation were attributed to the modification of passive film by the nitrogen ions. The scanning electron microscopy and electrochemical analyses of the ions implanted samples revealed an improvement in the pitting resistance of the alloy.