Anticorrosion Behaviour of SS304 Microgroove Surfaces in Saline Water

Abstract

The 304 Stainless Steel (SS304) is severely affected by salt water corrosion due to its high surface wettability. By reducing its surface wettability, its corrosion can be reduced. To achieve this, topographical modification of the steel surface is an effective route. In this work, SS304 flat surfaces were topographically modified into microgrooves (ridge width 250 μm to 500 μm, groove width 200 μm, width ratio = ridge width/groove width >1). Wire cut electrical discharge machining was used to fabricate the microgrooves. Long-term wetting characteristics and long-term corrosion behaviour of flat surface and microgrooves were studied. The influence of the nature of wetting of the tested surfaces on their corrosion behaviour was examined. The sessile drop method and potentiodynamic polarization tests in sodium chloride (3.5 wt. % NaCl) solution (intermittent and continuous exposures for 168 h) were studied to characterize their wetting and corrosion behaviours, respectively. Topographical modification imparted long-term hydrophobicity and, as a consequence, long-term anticorrosion ability of the steel surface. Micropatterning reduced the corrosion rate by two orders of magnitude due to reduction in interfacial contact area with the corrosive fluid via composite wetting, i.e., solid–liquid–air interface. Microgrooves showed corrosion inhibition efficiency ³88%, upon long-term exposure to NaCl solution. By comparing the wetting and corrosion behaviours of the microgrooves with those of the previously studied microgrooves (ridge width/groove width <1), it was found that the surface roughness of their ridges strongly influences their wetting and corrosion properties.

Patterning SS304 Surface at Microscale to Reduce Wettability and Corrosion in Saline Water

“…Micropatterning of metallic surfaces is an effective route to lower liquid-mediated corrosion [1]. Micropatterns can offer efficiency of corrosion inhibition that is comparable to those that are obtained by chemical modification of metallic surfaces [1].…”

“…Micropatterning of metallic surfaces is an effective route to lower liquid-mediated corrosion [1]. Micropatterns can offer efficiency of corrosion inhibition that is comparable to those that are obtained by chemical modification of metallic surfaces [1]. Micropatterns have several advantages over conventional approaches that mitigate corrosion such as thin films/coatings, electroplating, paints, and inhibitors, e.g., absence of interface between surface and corrosive media, devoid of complex chemical processes, easy to design and fabricate patterns of varying geometries (i.e., shape/size), multifunctionality (e.g., drag…”

“…Metals 2022, 12, 1137 2 of 12 reduction, antifouling, anti-frosting/icing, and antifriction [2][3][4]). The advantages of micropatterning of surfaces, in detail, are given in [1].…”

“…However, these studies [5][6][7][8][9][10] report one-time testing of corrosion of micropatterns. Recent work on hydrophobic SS304 microgrooves reports that micropatterning provides long-term antiwetting and long-term anticorrosion abilities [1]. Long-term examination of wetting and corrosion of micropatterns is important as it provides insights for application purposes.…”

“…between surface and corrosive media, devoid of complex chemical processes, easy to design and fabricate patterns of varying geometries (i.e., shape/size), multifunctionality (e.g., drag reduction, antifouling, anti-frosting/icing, and antifriction [2][3][4]). The advantages of micropatterning of surfaces, in detail, are given in [1]. Metallic micropatterns that have been reported to effectively reduce liquid-mediated corrosion include: microcell structures that are fabricated on aluminum surfaces by laser direct writing technique [5], patterns of micro-holes that are generated by laser ablation on nickel surfaces [6], micro-holes that are created on 316LVM stainless steel wires by focused ion beam (FIB) method [7], textures on SS316L that are produced by Nd:YAG nanosecond laser [8], chemically-etched microchannels on 304 stainless steel surfaces [9], and laser-textured and heat-treated aluminum 7075 alloy [10].…”