Corrosion-fatigue properties of plasma-based low-energy nitrogen ion implanted AISI 304 L austenitic stainless steel in borate buffer solution

Abstract

AISI 304L austenitic stainless steel was modified by using the plasma-based low-energy nitrogen ion implantation (PBLEII) at a process temperature of 400 o C for a processing time of 4 h in order to improve the corrosion-fatigue resistance of the austenitic stainless steel. A single high-nitrogen face-centered-cubic phase ( N) layer with a maximal nitrogen concentration of about 25 at.% was formed on the nitrogen-modified austenitic stainless steel. Compared with the original austenitic stainless steel, the γ N phase layer on the austenitic stainless steel possessed a significant improvement in corrosion resistance in the borate buffer solution with a pH value of 8.4. The corrosion-fatigue properties of the  N phase layer on the austenitic stainless steel were examined by the push-pull fatigue experiments with a ratio R of tensile and compression of-1 in the borate buffer solution. The  N phase layer has an increased corrosion-fatigue strength up to 230 MPa from 180 MPa of the original austenitic stainless steel with an apparent increase of about 28%. The corrosion-fatigue crack initiation in the  N phase layer was found as a controllable stage in the fracture process at the interface between the  N phase layer and the austenitic stainless steel matrix with the arc corrosion-fatigue source. Some tiny corrosion-fatigue striations were obtained on the corrosion-fracture surfaces of the  N phase layer. The high density of slip bands and dislocations in the  N phase layer was able to prevent the crack initiation and propagation, leading to improvement of the corrosion-fatigue properties in the borate buffer solution.

From Austenitic Stainless Steel to Expanded Austenite-S Phase: Formation, Characteristics and Properties of an Elusive Metastable Phase

“…Low temperature treatments also allow to increase corrosion-fatigue resistance, due to the improved corrosion resistance. Wang et al [206] tested plasma based low-energy N ion implanted (400 • C, 4 h) AISI 304L with push-pull fatigue experiments in a borate buffer solution at pH 8.4, and they found that corrosion-fatigue strength was about 230 MPa, significantly higher than that of untreated steel (180 MPa). Crack initiation occurred at the interface between the nitrided layer and the matrix, instead of at the surface, as for the untreated alloy.…”

Preparation and Performance of Nitrogen-containing Stainless Steel

“…The existed methods to produce nitrogen-containing austenitic steel include high pressure melting and high temperature gas nitriding etc. [5][6][7][8]. Unfortunately, these methods are hard to be carried out in practical applications; especially they are restricted by the demand of special equipments.…”

Thermal Spray Coatings of Al, ZnAl and Inconel 625 Alloys on SS304L for Anti-Saline Corrosion

“…These structural steels are being used everywhere in the world for their inherent mechanical properties, but there are problems related to corrosion in aqueous and marine environments. However, the mechanical property and corrosion resistance of AISI 304 austenitic stainless steel (SS304L) has been reported to change with sensitization [1][2][3][4][5][6]. The storage facilities are located in coastal nuclear power plants in the Pacific-rim region, such as in South Korea, Japan, and Taiwan [7][8][9].…”

“…The storage facilities are located in coastal nuclear power plants in the Pacific-rim region, such as in South Korea, Japan, and Taiwan [7][8][9]. The implanted nitrogen ions and chromium-base coatings are reported for enhancing the anti-corrosion abilities in solution and in high temperatures [3]. The thermal spray coatings are used for long-term protection on the metal surfaces of structures such as aircrafts, bridges, and wind turbine towers.…”