A double-layer mechanism for the complex-ion embrittlement of silver chloride

On the Activation Energy in the Chemical-Mechanical Correlation Model

“…Among the five SCC systems analyzed in this work, t f of both AgCl (Figure 1) and Al-4.2% Zn-2.5% Mg (Figure 2) were reported in the original sources to be dominated by propagation times. [4][5] For alloy 600 in high-temperature reactor coolant water, it is known that initiation takes a significant part in t f . However, the experimental data shown in Figure 3 for alloy 600 were measured at stresses > 400 MPa (yield strength: ~ 350 MPa).…”

“…These vacancies were believed to be the mechanical process responsible for SCC. 4 If this was true, then Q creep should be equal to the activation energy of the bulk diffusion of Ag v vacancies. The activation energy for Ag v diffusion was reported to be 31 kJ/mol in the temperature range between 24°C and 407°C.…”

“…The dynamic flow stress of the specimen, as determined at a strain rate of 2 x 10 -4 /s, was 3.04 MPa ± 0. vacancies beneath the surface of AgCl. 4 From Figure 1, the stress dependence of t f could be divided into three stages: significant decrease in t f with the increase of below 5 MPa; less significant decrease in t f with between 5 MPa and 10 MPa; and significant decrease again with above 10 MPa. These three stages became more obvious as the temperature increased to 100°C.…”

“…8 Figure 1 shows six sets of data of t f vs for polycrystalline AgCl in 17 N AgNO 3 solutions presaturated with Ag 3 Cl 2+ at constant temperatures from 24°C to 100°C, based upon work by Westwood, et al. 4 These data were measured under constant loading with tensile specimen (10 mm by 3 mm by 1 mm [0.394 in. by 0.118 in.…”

“…The experimental data analyzed included: -Polycrystalline AgCl in 17 N silver nitrate (AgNO 3 ) solutions presaturated with silver chloride complex ions (Ag 3 Cl 2+ ), as measured by Westwood, et al; 4 -␣ Al-4.2% Zn-2.5% Mg in 1 M sodium chloride (NaCl) solution, as measured by Helfrich; 5 -Alloy 600 in 360°C pressurized water, as measured by Tsuruta, et al; 6 and -Cu-0.1% to 10% Zn in 0.05 M ammonia (NH 3 OH) solutions, as measured by Suzuki; 7 and Cu-10% to 40% Zn in Cu-tetramine solutions, as measured by Graf and Witticb. 8 Figure 1 shows six sets of data of t f vs for polycrystalline AgCl in 17 N AgNO 3 solutions presaturated with Ag 3 Cl 2+ at constant temperatures from 24°C to 100°C, based upon work by Westwood, et al.…”