An attempt to detect SCC by combined measurements of electrochemical noise and acoustic emission

摘要

Electrochemical voltage and current noise (EN) were measured simultaneously with acoustic emission (AE) during intergranular stress-corrosion cracking (IGSCC) on tensile specimens under a constant load. The elongation of the test specimens was also measured continuously during the tests, as an additional measuring technique. The test specimens were made from sensitized stainless steel of type 304, and immersed in an aqueous solution of sodium thiosulphate. The main aim of our work was to find out how successfully IGSCC processes could be detected by the simultaneous use of all three measurement methods. The results of the tests indicated that the accumulation of cracking and dissolution events could be satisfactorily monitored, whereas it was not possible to detect individual IGSCC events with the existing measuring set-up. It is not clear whether this inability to detect single IGSCC events was a consequence of the continuous nature of the IGSCC processes, or whether it was due to the insufficient resolution of the measurement system set-up.