Chromium Recoil Implantation Into SAE 1020 Steel By Nitrogen Ion Bombardment

SAE 1020 is a widely used plain carbon steel, as mortar reinforcement in buildings and small machine parts. But aside from good mechanical properties, its surface suffer from severe corrosion and high wear rate, due to modest hardness. Chromium (Cr) in excess of 12% in Fe alloys renders them resistant to several corrosive attacks. So we tried to introduce Cr in such amounts into the surface of that steel. Cr films were deposited by electron beam on SAE 1020 steel. Bombarding the Cr film either by nitrogen Plasma Immersion Ion Implantation (PIII) or nitrogen ion beam (IB), Cr atoms were recoil introduced into the Fe matrix. Normally, in the recoil process, heavy atoms are used, but in this set of experiments we used a relatively lighter atom, viz. nitrogen. SRIM simulation was used to show Cr atoms range in the steel matrix after being hit by nitrogen atoms. AES analysis showed ranges far beyond the calculated figures and in percentages above 13at. %, enough to the purposes of these works. Preliminary corrosion results showed remarkable enhancement under corrosive attack.