Improvement in the Corrosion Resistance of Austenitic Stainless Steel 316L by Ion Implantation

Abstract

In the present work, austenitic stainless steel 316L (SS316L) samples were implanted with Ni and Ni-Cr. A nickel-rich layer about 100 nm in thickness and a Ni-Cr enriched layer about 60 nm thick are formed on the surface of SS316L. The effects of ion implantation on the corrosion performance of SS316L are investigated in a 0.5 M H 2 SO 4 with 2 ppm HF solution at 80℃ by open circuit potential (OCP), potentiodynamic and potentiostatic tests. The samples after the potentiostatic test are analyzed by XPS. The results indicate that the composition of the passive film change from a mixture of Fe oxides and Cr oxide to a Cr oxide dominated passive film after the potentiostatic test. The solutions after the potentiostatic test are analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). The results reveal that Fe is selectively dissolved in all cases and a proper Ni and Ni-Cr implant fluence can greatly improve the corrosion resistance of SS316L in the simulated polymer electrolyte membrane fuel cells (PEMFCS) environment. They are in agreement with the electrochemical test results that the bare SS316L has the highest dissolution rate in both cathode and anode environments and the Ni and Ni-Cr implantation reduce markedly the dissolution rate. After the potentiostatic test the interfacial contact resistance (ICR) values are also measured. Ni and Ni-Cr are enriched in the passive film formed in the simulated PEMFC cathode environment after ion implantation thereby providing better conductivity than that formed in the anode one. A significant improvement of ICR is achieved for the SS316L implanted with Ni and Ni-Cr as compared to the bare SS316L, which is attributed to the reduction in passive layer thickness caused by Ni and Ni-Cr implantation. The ICR values for implanted specimens increase with increasing dose.

Stoichiometric titanium dioxide ion implantation in AISI 304 stainless steel for corrosion protection

“…oxides) or by alloying the surface with elements that increase the formation of the natural passivation layer of the steel. While the applicability for corrosion protection of a lot of elements and compounds, like N, Ni, Cr, Mo, Si, Ce, Y, Er, ZrN, TiN was proved using various coating or surface modification techniques (PVD, arc plasma deposition, plasma nitriding, ion implantation) [2][3][4][5][6][7][8], one material in particular gets increasing interest in corrosion science: Titanium dioxide [9][10][11][12][13]. In addition to its property as a photocatalyst, titanium dioxide is especially distinguished in its capacity as a highly chemical inert oxide.…”

“…Alternative techniques such as ion implantation could provide a way to avoid those issues inherent to deposition methods. Although ion implantation of various elements and even titanium in stainless steel was investigated [15,4,3,7], to the author's best knowledge no synthesis of TiO 2 by stoichiometric sequential ion implantation of the elements Ti and O into AISI 304 stainless steel has been reported so far. The intention of this work is to investigate the influence of typical implantation parameters, such as energy and fluence of implanted ions on the corrosion behavior of stoichiometric TiO 2 -implanted AISI 304 steel.…”