EFFECT OF CU(II) CONCENTRATION ON THE STR ESS-CORROSION-CRACKING SUSCEPTIBILITY OF ALPHA-BRASS - APPLICATION OF THE SURFACE-MOBILITY STRESS-CORROSION CRACKING MECHANISM

The stress corrosion cracking (SCC) susceptibility of alpha-brass was studied in Cu(II) solutions of several concentrations. SCC was found i n all the solutions tested. The log crack propagation rate (c.p.r.) wa s found to be a linear function of the log Cu(II) concentration. The s lope of this plot is similar to the one found in the log exchange curr ent density vs. log Cu(II) concentration relationship. According to th e surface mobility SCC mechanism, the rate controlling steps in this s ystem is the exchange metal-metal ion which induces a high surface mob ility.