Deliquescence of NaCl and Atmospheric Corrosion of 316L Stainless Steel

2017 ◽  
Vol 1142 ◽  
pp. 8-13
Author(s):  
Ahmed Al Mehrzi ◽  
Yong Sun Yi ◽  
Pyung Yeon Cho ◽  
Sara Al Saadi ◽  
Ji Sung Lee ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Relative Humidity ◽  
Atmospheric Corrosion ◽  
Steel Surface ◽  
316L Stainless Steel ◽  
Chloride Concentration ◽  
Atmospheric Condition ◽  
Stainless Steel Surface ◽  
Surface Films ◽  
Pit Initiation

Water droplets formed by the deliquescence of pre-deposited NaCl on 316L stainless steel were investigated. Different total weights of NaCl particles between 0.0005 g and 0.01 g were deposited on 316L stainless steel surface, which were exposed to an atmospheric condition at 80oC and relative humidity of 80% until NaCl droplets were stabilized. The volume of NaCl droplet was linearly proportional to the total weights of pre-deposited NaCl and consequently the chloride concentration in droplets, ranging from 3 to 6 M, did not depend on the NaCl weights. After exposed to the NaCl droplets at 80oC and relative humidity of 80% over 5, 10, and 15 days, all 316L stainless steel samples suffered from pitting. The Cl- ions in the surface films of samples were measured by ToF SIMS. The pit densities on samples were well correlated with the Cl- intensities in the surface films. These results suggest that the pit initiation under NaCl droplets by deliquescence is caused by the Cl- ions either incorporated into surface films or penetrated through them.

scholarly journals Synthesis and Characterization of New Polymers Bearing Tetrazole and Triazole Moieties with Studying their Corrosion Protection of Stainless Steel Surface in Hydrochloric Acid

2020 ◽  
pp. 2467-2478
Author(s):  
Amaal S. Sadiq ◽  
Entesar O. Al-Tamimi
Keyword(s):  
Stainless Steel ◽  
Corrosion Protection ◽  
Steel Surface ◽  
316L Stainless Steel ◽  
Electrochemical Polymerization ◽  
Triazole Ring ◽  
Phenyl Isothiocyanate ◽  
Stainless Steel Surface ◽  
Nano Materials ◽  
Atomic Force

A series of polymers containing1,2,4-triazole  and tetrazole groups in their main chains were synthesized through several steps. Poly(acryloyl hydrazide) was first prepared and then subjected to a hydrazide reaction with phenyl isothiocyanate to give a 1,2,4-triazole ring (2). This polymer was introduced into a reaction with chloro acetylchloride to yield polymer (3), which was refluxed with sodium azide to give polymer (4). Polymer (5) was synthesized by the reaction of polymer (4) with  acrylonitrile in the presence of NH4Cl as a catalyst. Finally, polymer (6) was synthesized by the electrochemical polymerization of polymer (5) using  316L stainless steel as an anti-corrosion coating. Polymer-coated and uncoated stainless steel was tested for corrosion safety in a solution of 0.1 M HCl, followed by Tafel and Potentiostatic procedures at a temperature of 293 K. Nano materials such as ZnO were applied to the monomer solution at different concentrations to enhance the corrosion resistance of the 316L stainless steel surface. The results showed that the performance values of corrosion protection for the polymer coating were increased with the introduction of the nano materials. Furthermore, 13C-NMR, 1H-NMR, and FTIR were recorded to confirm the structures of the poylmers, while their physical properties were tested using atomic force microscope (AFM) and scanning electron microscope (SEM).

The Influence of Process Parameters on Structure of YSZ Coating Deposited by Plasma Spraying on AISI 316L Stainless Steel Surface by APS Method and on Ti6Al4V Titanium Alloy Surface by PS-PVD Method

2021 ◽  
Vol 1016 ◽  
pp. 1166-1174
Author(s):  
Maciej Pytel ◽  
Tadeusz Kubaszek ◽  
Paweł Pędrak ◽  
Marek Góral ◽  
Marcin Drajewicz
Keyword(s):  
Stainless Steel ◽  
Titanium Alloy ◽  
Plasma Spray ◽  
Steel Surface ◽  
316L Stainless Steel ◽  
Stainless Steel Surface ◽  
Aisi 316L ◽  
Aisi 316L Stainless Steel ◽  
Ti6al4v Titanium Alloy ◽  
Ysz Coating

The plasma spraying is commonly used in medical application. The Atmospheric Plasma Spray (APS) method was applied for production of yttria-stabilized zirconia (YSZ) on AISI 316L stainless steel surface and also on Ti6Al4V titanium alloy surface. In present article two examples of coatings production were presented. In first experimental the YSZ was plasma sprayed (APS) on 316L stainless steel surface. The coating was deposited using A60 (Thermico) plasma torch. The initial parameters were selected and it was concluded that minimal power current was 500A. The thickness of obtained coating was in range 100-150 micrometers. The X-ray phase analysis showed the presence of tetragonal t-phase of ZrO2. The lamellar structure of coatings with large porosity was observed. In second experimental the newly developed Plasma Spray Physical Vapor Deposition method (PS-PVD) was used. The YSZ coating was deposited on titanium Grade 5 surface. The conducted research showed the formation of two types of coatings structure. When the power current was lower (2000 A) the dense lamellar-like coatings was obtained. If the power current was increased (up to 2200A) the columnar ceramic coating was observed.

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