Detecting Critical Crevice Temperature for Duplex Stainless Steels in Chloride Solutions

CORROSION ◽  
2011 ◽  
Vol 67 (2) ◽  
pp. 025004-1-025004-7 ◽  
Author(s):  
D. Han ◽  
Y. Jiang ◽  
B. Deng ◽  
L. Zhang ◽  
J. Gao ◽  
...  
Keyword(s):  
Stainless Steels ◽  
Crevice Corrosion ◽  
Electrochemical Method ◽  
Duplex Stainless Steels ◽  
Good Reproducibility ◽  
X Ray ◽  
Initiation Step ◽  
Critical Pitting Temperature ◽  
Preferential Dissolution ◽  
Scanning Electron

Abstract A simple and rapid electrochemical method for the evaluation of crevice corrosion in duplex stainless steels (DSS) is described. Three types of DSS—namely, UNS S32101, UNS S31803, and UNS S32750—were tested in 1 mol/L sodium chloride (NaCl) solutions. Results showed good reproducibility with a typical standard deviation of below 3°C. The critical pitting temperature (CPT) for the same specimens was also investigated in 1 mol/L NaCl solutions. An approximately 20°C decrease from CPT to critical crevice temperature (CCT) was observed and subsequently explained. Then, the morphologies of crevice corrosion were studied using scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM/EDS) method. The SEM/EDS study revealed that the ferrite phase was the site where preferential dissolution took place at the initiation step of crevice corrosion, which was in accordance with the prediction by calculating the critical crevice index. Moreover, repassivation was detected with the development of crevice corrosion. The reason was clarified by combining the results obtained with a successful diffusion model, and eventually the crevice corrosion progress was illustrated schematically.

Crevice corrosion of duplex stainless steels in natural and chlorinated seawater

2011 ◽  
Vol 108 (7-8) ◽  
pp. 451-463 ◽  
Author(s):  
N. Larché ◽  
D. Thierry ◽  
V. Debout ◽  
J. Blanc ◽  
T. Cassagne ◽  
...  
Keyword(s):  
Stainless Steels ◽  
Crevice Corrosion ◽  
Duplex Stainless Steels

scholarly journals Atmospheric Plasma Spraying (APS) and Alloying as Methods to Modify Properties of the SSS Surface Layers

2020 ◽  
Vol 22 (4) ◽  
pp. 80-89
Author(s):  
Barbara Lisiecka ◽  
Agata Dudek ◽  
Robert Ulewicz
Keyword(s):  
Automotive Industry ◽  
Stainless Steels ◽  
Arc Welding ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Surface Layers ◽  
X Ray ◽  
Gas Tungsten Arc ◽  
Roughness Measurements ◽  
Scanning Electron

Use of the powder metallurgy (PM) in production of various components has been growing in the automotive industry, including production of sintered stainless steels (SSSs). This study aims to improve the functional properties of SSSs by formation of the Cr3C2-NiCr coating by APS method. The next stage involved alloying of the surface of SSSs using the gas tungsten arc welding (GTAW). Analysis of microstructures was carried out using microscopy (metallographic microscope and scanning electron microscope). Furthermore, the study presents XRD (X-ray powder diffraction) examinations, mechanical properties and surface roughness measurements. The presented modification improved properties of the surface layers examined in the study and enabled a reduction in the wall thickness of the detail, which is important factor in the automotive and transport industry.

Electrochemical Synthesis and Photocatalytic Activity of Differently Shaped CuOx Particles

2017 ◽  
Vol 13 ◽  
pp. 330-333
Author(s):  
Anna Ulyankina ◽  
Igor Leontyev ◽  
Nina Smirnova
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Electrochemical Method ◽  
Spherical Particles ◽  
Photocatalytic Efficiency ◽  
X Ray Diffraction ◽  
X Ray ◽  
Polyhedral Particles ◽  
Copper Electrodes ◽  
Scanning Electron

CuOx powders with diff erently shaped particles were firstly prepared via an electrochemical method by oxidation and dispersion of copper electrodes in an electrolyte solution under pulse alternating current (PAC). By means of X-ray diffraction (XRD) and scanning electron microscopy (SEM) the current density is found to have an influence on the morphology and composition of CuOx particles. Photocatalytic efficiency of CuOx towards methyl orange (MO) degradation under visible light was investigated. The prepared polyhedral particles show the best photocatalytic activity of 81 % towards MO comparing to octahedral and spherical particles with 70 and 61 %, respectively.

Influence of Oxygen Concentration on the Initiation of Dissolution Corrosion on 316L Austenitic Stainless Steel at 450°C

2017 ◽  
Author(s):  
Oksana Klok ◽  
Konstantina Lambrinou ◽  
Serguei Gavrilov ◽  
Iris De Graeve
Keyword(s):  
Electron Microscopy ◽  
Oxygen Concentration ◽  
Stainless Steels ◽  
Austenitic Stainless Steels ◽  
X Ray ◽  
First Results ◽  
316L Steel ◽  
316L Austenitic Stainless Steel ◽  
Dissolution Corrosion ◽  
Scanning Electron

This work presents first results of the study on the influence of the LBE oxygen concentration on the initiation of dissolution corrosion in 316L austenitic stainless steels. 316L steel specimens were exposed at 450 °C to static liquid LBE with controlled and constant oxygen concentration of 10−5, 10−6 and 10−7 mass% for 1000 hours. Corroded specimens were analysed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Limited oxidation corrosion and no dissolution corrosion was observed in the specimens exposed to LBE containing 10−5 and 10−6 mass% oxygen, while dissolution corrosion with a maximum depth of 59 μm was found in the specimen exposed to LBE containing 10−7 mass% oxygen.

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