In situmeasurement of corrosion of type 316L stainless steel in 553 K pure water via the electrical resistance of a thin wire

Abstract

A system for the in situ monitoring of corrosion depth via electrical resistance measurements was applied to study the corrosion rate of type 316L stainless steel at 553 K in pure water. Corrosion depth was measured using a 50 mm diameter wire probe mounted axially in the tube. Measurements were in good agreement with literature data for both the hydrogen water chemistry (HWC) condition and the normal water chemistry (NWC) condition. Oxide film analyses by scanning electron microscopy and laser Raman spectroscopy on the wire probe and the tube showed no effects from shape of the test specimens or the application of electric current. Corrosion kinetics was evaluated by fitting equations to the measurements. Data for the HWC condition could be fitted by a two-step logarithmic-parabolic law. A single-step logarithmic law fitted data for the NWC condition. Changes in corrosion rate by the water chemistry changes were readily detected with the technique. Corrosion depth change could be observed for the water chemistry change from the NWC condition to the HWC condition with electrochemical corrosion potential (ECP) of 70.56 V vs. standard hydrogen electrode, which is lower than the ECP that the phase of iron oxide changes from a-Fe 2 O 3 to Fe 3 O 4 .

Investigation of cobalt buildup behavior and suppression by zinc injection on stainless steel under HWC conditions using simultaneous continuous measurements of corrosion and cobalt buildup

“…Figure 4(a) shows the entire immersion time and Figure 4(b) shows the initial 50 h with an expanded time scale. The corrosion amounts of the 316L SS under HWC conditions without Zn, which were reported by Ishida and Lister [11], are also plotted. Our results and those of the previous report agreed with each other within a margin of error of 10%.…”

“…The corrosion amount of 316 SS was measured by PDM, which can continuously evaluate the corrosion amount using electrical resistance measurements. Details of PDM have been described elsewhere [11]. In this work, "corrosion amount" means the decreased amount of the base metal due to oxidation and elution.…”

Revealing How Alkali Cations Affect the Surface Reactivity of Stainless Steel in Alkaline Aqueous Environments

“…23 Kosmotropes are attracted to hydrophilic surfaces and repelled from hydrophobic ones. 23,33 On the other hand, chaotropes are relatively more attracted to hydrophobic surfaces following the solubility rule that “like dissolves like”. 23,31 This suggests that hydrated Li + ions exhibit a stronger ion–surface interaction with the hydrophilic steel surface, resulting in ion adsorption and disruption of the EDL, a region consisting of two oppositely charged layers at the interface of two different phases in solution, 33 that persists on the surface of the steel.…”

“…Figure 3 shows that the first layer of the EDL on stainless steel is composed of the following: a positively charged surface due to the work function difference between the steel and the solution; 43 the Stern layer (∼1 nm thickness), 34 which consists of the inner Helmholtz plane (composed of counterions, e.g., – OH ions in alkaline solutions, and solvent molecules, e.g., water); outer Helmholtz plane (composed of hydrated cations attracted toward the surface); and the diffuse layer (where ions and molecules feature higher mobility). 33 Partial dehydration of the strongly hydrated Li + ions is suggested to occur on the water-deficient steel surface although the first hydration sphere is retained. 31 It is postulated that the dehydrated Li + ions will acquire – OH ions (displaced from the Stern layer 35,36 after surface dehydration of Li + ions) from the steel surface and water molecules present in the EDL.…”

Removal of nitrogen containing reducing agents from water coolant systems using ion exchange resin and membranes

“…It is widely reported that oxidants present in water are responsible for corrosion of the structural materials; which negatively impacts the safety and economy of a plant. In nuclear reactor coolant systems the main oxidants are (i) dissolved oxygen and (ii) hydrogen peroxide produced by radiolysis of the water , . Reducing agents are added to suppress the formation of these oxidants.…”