RI 8431 Electrochemical Corrosion Behavior of Alloys Formed by Ion Implantation

The Bureau of Mines, U.S. Department of the Interior, is conducting research to devise substitute corrosion-resistant materials by using ion implantation to form alloyed regions near the surfaces of metals. These alloys were prepared by implanting 25-kev Cr+ and/or Ni+ ions into iron. Their resistance to corrosive attack was evaluated by determining their anodic polarization behavior under potentiodynamic conditions in a solution containing sodium chloride, boric acid, and sodium borate. These electrochemical studies have shown that the general corrosion resistance of ion-implanted alloys was comparable to nominally equivalent bulk alloys. The pitting-corrosion resistance of the ion-implanted alloys was superior to that of iron, although not as good as that of most of the bulk alloys tested.