The determination of pH, potential and chloride concentration in corroding crevices on 304 stainless steel and 7475 aluminium alloy

AbstractAlloy 22 [UNS N06022] is now being considered for construction of high level waste containers to be emplaced at Yucca Mountain and elsewhere. In essence, this alloy is 20.0–22.5% Cr, 12.5–14.5% Mo, 2.0–6.0% Fe, 2.5–3.5% W, with the balance being Ni. Other impurity elements include P, Si, S, Mn, Co and V. Cobalt may be present at a maximum concentration of 2.5%. Detailed mechanistic models have been developed to account for the corrosion of Alloy 22 surfaces in crevices that will inevitably form. Such occluded areas experience substantial decreases in pH, with corresponding elevations in chloride concentration. Experimental work has been undertaken to validate the crevice corrosion model, including parallel studies with 304 stainless steel.

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Susceptibility of 304 Stainless Steel to Crevice Corrosion in Electrochemically Active Fluids

CORROSION ◽

10.5006/3324 ◽

2020 ◽

Vol 76 (4) ◽

pp. 424-435

Author(s):

Abinaya Kamaraj ◽

Johann Wilhelm Erning

Keyword(s):

Stainless Steel ◽

Crevice Corrosion ◽

Chloride Concentration ◽

304 Stainless Steel ◽

Water Composition ◽

Polyether Ether Ketone ◽

Electrochemically Active ◽

Ether Ketone ◽

Type 304 ◽

Type 304 Stainless Steel

The susceptibility of Type 304 stainless steel (SS) to crevice corrosion upon contacting with electrochemically active fluids was investigated using exposure tests and stepwise potentiostatic polarization. Crevice materials made of 304 SS and polyether ether ketone (PEEK) were focused on in this study. The combined influence of oxidant and chloride concentration on crevice corrosion was examined in detail in the two types of crevice combinations (304 SS-to-PEEK and 304 SS-to-304 SS). The 304 SS specimens were strongly susceptible to crevice corrosion when coupled with 304 SS. Even at a low concentration of 5 mg/L free chlorine and 150 mg/L chloride, which is below nominal dilutions in beverage industries, the examined specimens underwent crevice corrosion in both crevices. The effect of water composition on crevice corrosion was also studied, indicating high susceptibility of 304 SS to crevice corrosion in low pH (pH ≤ 5) solutions. The corroded surface morphology was analyzed using scanning electron microscope, energy dispersive x-ray, and confocal microscope.

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Electrochemical noise analysis in the frequency domain and determination of corrosion rates for SS-304 stainless steel

Materials Science and Engineering A ◽

10.1016/j.msea.2006.07.078 ◽

2006 ◽

Vol 435-436 ◽

pp. 439-446 ◽

Cited By ~ 14

Author(s):

C. Cuevas-Arteaga ◽

J. Porcayo-Calderón

Keyword(s):

Stainless Steel ◽

Frequency Domain ◽

Electrochemical Noise ◽

Noise Analysis ◽

304 Stainless Steel ◽

Corrosion Rates ◽

Ss 304

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DESIGN, CONSTRUCTION AND EVALUATION OF A THERMAL CONDUCTIVITY METER BASED ON ASTM E1225 STANDARD

Revista de Engenharia Térmica ◽

10.5380/reterm.v15i1.62156 ◽

2016 ◽

Vol 15 (1) ◽

pp. 20

Author(s):

L. L. Manetti ◽

I. Dias Jr ◽

I. S. Kiyomura ◽

R. C. Cavalcanti ◽

F. B. Pagliosa

Keyword(s):

Thermal Conductivity ◽

Stainless Steel ◽

Cooling System ◽

Material Selection ◽

304 Stainless Steel ◽

Cylinder Block ◽

Electric Resistance ◽

Future Goals ◽

Design Construction

The focus of this work is the design, construction and evaluation of a thermal conductivity meter apparatus based on ASTM E- 1225 standard. The thermal conductivity is a heat-transport propriety and with the development of new materials the determination of thermophysical properties for its correct use becomes necessary. The apparatus was projected in CAD software and the material selection was done following the standard recommendations. For the meter bars were used 304 stainless steel, since its thermal conductivity is known. The heater was made with an aluminum cylinder block and a cartridge electric resistance. The cooling system was assembled using a Peltier thermoelectric plate and a fin heat sink equipped with a fan. Lastly, a steel pipe was used for building the guard cylinder. In order to evaluate the apparatus, the first specimen tested was the 304 stainless steel, the same material as the meter bars. The result of thermal conductivity showed an error of 6% relative to the value found in literature. However, in this test the temperature of isothermal guard cylinder was lower than the temperature required by the standard. Thus, the future goals will be the development of a temperature control for the guard cylinder and realization of more tests with different materials.

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