The effects of solution pH (0.3-8.52), chloride concentration (1-5 M), and temperature (25-80 degrees C on the corrosion resistance and the susceptibility to stress corrosion cracking (SCC) of the nickel-based Alloy 690 in NaCl solutions were investigated using a cyclic polarization method and a slow strain rate tensile (SSRT) test, respectively. It was found that the extent of the passive range becomes narrower and the polarization current density becomes larger with a decrease in the solution pH and an increase in the chloride concentration at 25 degrees C. In addition, the mechanical properties, such as the maximum tensile strength (NITS), fracture strain (FS), and reduction in area (RA) decreased significantly at pH < 3 in 5 M NaCl at 25 degrees C. On the other hand, SCC was also found to be induced in NaCl solutions at pH 1 if the chloride concentration was higher than 1 M. Through the cyclic polarization curves, the corrosion rates determined by linear polarization methods, and the results of SSRT, the corrosion resistance and SCC susceptibility of Alloy 690 in 1 M NaCl at pH 1 were found to be more sensitive to a variation in the solution temperature than in the other critical environment (5 M NaCl at pH 3). The SSRT results are consistent with fractography and side-view observations of the tested specimens by SEM. (c) 2005 Elsevier B.V. All rights reserved.