The Critical Pitting Chloride Concentration of Various Stainless Steels Measured by an Electrochemical Method

2018 ◽  
Vol 165 (14) ◽  
pp. C939-C949 ◽  
Author(s):  
Xuan Wu ◽  
Yangting Sun ◽  
Yuanyuan Liu ◽  
Yuanyuan Yang ◽  
Jin Li ◽  
...  
Keyword(s):  
Stainless Steels ◽  
Electrochemical Method ◽  
Chloride Concentration

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.

scholarly journals COD reduction studies of paper mill effluent using a batch recirculation electrochemical method

2011 ◽  
Vol 13 (3) ◽  
pp. 37-41
Author(s):  
T. Kannadasan ◽  
V. Sivakumar ◽  
C. Basha ◽  
Arun Parwate ◽  
K. Senthilkumar ◽  
...  
Keyword(s):  
Electrochemical Method ◽  
Supporting Electrolyte ◽  
Chloride Concentration ◽  
Paper Mill ◽  
Electrochemical Reactor ◽  
Pulp And Paper ◽  
Pulp And Paper Mill ◽  
Cod Reduction ◽  
Paper Mill Effluent ◽  
Reservoir Volume

COD reduction studies of paper mill effluent using a batch recirculation electrochemical method The conventional method of treating pulp and paper mill effluent involves the biological oxidation by bacterial action of aerobic and anaerobic conditions and aerobic lagooning method, which are less efficiency of removing COD. To overcome the drawbacks of the existing treatment process, in the present work an attempt has been made to study the electro oxidative destruction of the pulp and paper mill effluent using an electrochemical method and the effect of various parameters such as concentration of supporting electrolytes, current densities, flow rates of electrolyte and reservoir volumes of the effluent were conducted. From the experimental results it is observed that the rate of reduction of COD of the effluent increased with an increase in the supporting electrolyte (sodium chloride) concentration, current density where as it decreased with increase in the reservoir volume and the flow rate of electrolyte. The residence time distributions studies have also been conducted to study the behavior of the electrochemical reactor.

scholarly journals Corrosion Resistance to Chloride of a Novel Stainless Steel: The Threshold Chloride Value and Effect of Surface State

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2235
Author(s):  
Hailong Wang ◽  
Yuanjian Wu ◽  
Xiaoyan Sun ◽  
Jiayan Ling ◽  
Daoqin Zou
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Surface State ◽  
Steel Surface ◽  
Chloride Concentration ◽  
Surface Damage ◽  
Carbon Steels ◽  
The Novel ◽  
Rc Structures

To evaluate the corrosion resistance of a novel stainless steel intended for use within reinforced concrete (RC) structures exposed to aggressive environments, the threshold chloride concentration of three stainless steels (316, 2205, novel 2205) and two carbon steels (HRB400, HRB500) exposed to pore solutions of fresh concrete was experimentally studied by means of electrochemical methods. The effect of steel surface state on the corrosion resistance was also experimentally investigated. The results showed that the novel stainless steel has a much higher corrosion resistance than those of the carbon steels and stainless steels when subjected to chloride environments. The presence of surface damage leads to significant decrease of corrosion resistance for carbon steel, however the corrosion can be certainly inhibited with the accumulation of rust on the steel surface. Although the oxide layer was worn, the novel 2205 stainless steel still has a great corrosion resistance.

Corrosion-resistant alloys in chloride solutions: materials for surgical implants

1966 ◽  
Vol 294 (1439) ◽  
pp. 486-510 ◽  
Keyword(s):  
Current Density ◽  
Stainless Steels ◽  
Chloride Concentration ◽  
Body Fluids ◽  
Physiological Solution ◽  
The Body ◽  
Chloride Solutions ◽  
Corrosion Resistant ◽  
Surgical Implants ◽  
Current Densities

The behaviour of a number of corrosion-resistant alloys in chloride solutions, in Hanks’s physiological solution (simulating the extracellular body fluids) and as surgical implants has been investigated by electrochemical means, namely potential-time curves for isolated specimens, potential-current density curves for anodes, and current density-time curves for anodes maintained electronically at constant potential. Microscopical observation of pitting attack has also been made. Alloys based on iron (e. g. stainless steels), nickel (e. g. Inconel, Nimonic 75, etc.), cobalt (Vitallium), titanium and tantalum exposed to chloride solutions all show a range of potential in which they are passive, and, at sufficiently high chloride concentration and sufficiently positive potential, breakdown giving rise to pits that are electrobrightened. This general phenomenon occurs, in 0·17M sodium chloride solution, at 0·2 to 0·5 V (normal hydrogen scale) for stainless steels, ca . 0·9 V for the cobalt·based alloys, and ca . 20 to 30 V for certain titanium alloys and tantalum. In the passive range, all the alloys show anode current densities in the range 10 -6 to below 10 -9 A/cm 2 , the smaller current densities given by the most passive alloys (e. g. titanium-5 % niobium) often tending to decrease yet further with passage of time. We conclude that stainless steels (even of the higher chromium-nickel quality) and nickel alloys are unlikely to resist all breakdown by pitting when exposed to the body fluids (or other media containing chloride) indefinitely; that the cobalt-based alloys may well withstand such exposure for very long times; and that titanium and (especially) some of its alloys should withstand such exposure for an indefinite period. The (extremely slow) passage of cobalt and titanium into the environment is caused by passage of cations through their passivating oxide films, without breakdown.

Sign in / Sign up

Export Citation Format

Share Document