Experimental confirmation of the surface mobility-stress corrosion cracking mechanism: Ag-15Pd, Ag-15Au and Ag- 30Cd alloys in halide and sulphate containing solutions

Abstract The stress corrosion cracking susceptibility of Ag-15Pd and Ag-15Au alloys was studied in I M KCl, KBr, Kl and Na 2 SO 4 solutions. These studies were complemented with measurements on an Ag-30Cd alloy in 1 M KCl, HCl and 10% FeCl 3 solutions, where only de-alloying was detected; and on an Ag-15Pd alloy in iodine-saturated organic solvents, where crack velocities similar to those in a 1 M Kl solution were measured. The predictions of the surface mobility-SCC mechanism were supported by the present experimental results. De-alloying was found to be either a parallel or a competing process rather than the cause of SCC since de-alloying is dependent on surface mobility.