Temperature Dependence of Crevice Corrosion Initiation on Titanium Grade-2

Abstract

The temperature dependence of crevice corrosion initiation on titanium grade-2 has been investigated using a galvanic coupling technique. The film breakdown/repassivation transients indicate a temperature threshold, around 65°C, for the initiation of crevice corrosion. The number, size, frequency, and background current of these events increased when the temperature was increased from 65 to 80°C. Analysis of single transients suggests that the temperature also has an effect on the repassivation mechanism. Image analysis of corroded coupons reveals that crevice initiation and deeper penetration occur around the edge of the creviced area. Surface studies using electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy show oxide film flaws accompanied by water incorporation at temperatures above the 65°C threshold. Under creviced conditions, the occurrence of film flaws is the key process leading to the development of acidity and the initiation of crevice corrosion.

Hydrogen absorption into alpha titanium in acidic solutions

“…5 shows the potential transients recorded in a series of galvanostatic experiments performed in 0.27 mol L −1 NaCl + 0.60 mol L −1 HCl over the applied current density range of 0.01-3 mA cm −2 . This range covers that expected for proton reduction currents inside propagating crevices on Ti-2 [8][9][10][11]. A higher HCl concentration, compared to that employed in potentiostatic experiments, was used to ensure the formation of surface hydride in these experiments.…”

“…We have undertaken extensive studies on the crevice corrosion of alpha titanium materials, with a primary emphasis on determining the influence of environmental [8,9] and metallurgical [10,11] variables on the accumulation of corrosion damage. These studies show that ≥80% of the crevice corrosion processes sustained is driven by proton reduction within the acidified crevice area, a process that leads to considerable hydrogen absorption by the active metal surface [12].…”

Crevice Corrosion of Titanium in High Temperature-Concentrated Chloride Environments

“…These salts can hydrolyze to produce hydrochloric acid. The corrosion behavior of titanium in such media has long been attracting the attention of researches as well as the titanium industry (Ref [8][9][10][11][12][13][14][15][16].…”

Crevice Corrosion of Grade-2 Titanium in Saline Solutions at Different Temperatures and Oxygen Concentrations

“…• C) individual corrosion events were stifled more rapidly at higher temperatures 9 and the duration of active crevice corrosion in 0.27 mol/L NaCl at 102…”

“…9 For crevice corrosion initiated and propagated at constant temperature, the propagation rate is higher and the duration shorter at higher temperatures. 11 The overall amount of corrosion damage, as determined by weight change, is greater at higher temperatures, even though the consumption of O 2 in the corrosion process is less.…”