Ele ctrochemical Noise Analysi s of Pittin g Corrosion of Al uminum ۷۰۷۵

Variou s concepts d eveloped in the framework of wavelet transforms have been adapt ed to the analysis of electrochemical n oise measur ements (E NM). Wavelet transforms are pro posed as an alternative tool to overcome the limitations of FFT in the an alysis of EN M data.[۱] Wavelet analysis has been us ed as an i ndicator of specific corrosion mechanisms; different timescales of the current and potential signal coul d be attribu ted to diff usion, activation or mixed controlled p rocesses. A relatively fast or slo process c orresponds to smaller or larger timescales, respectively. The occurrenc e of metastable pitting is a small timescale process associated with initiation and growth of a pit emb ryo. This is generally assumed to occur prior to other types of localiz ed corrosio n, and therefore may be a considerably faster process than processes associatedwith larger timescales such as general corrosion, anodic dissolution, ion diffusion or removal of corrosion products. I n addition, the relative energy distribution of medium time scale crysta ls may be associated with pittin g propagation and growth.[۲]

کلیدواژه ها:

corrosi on ، electrochemical noise ، pitting ، wavelet transforms ، Aluminum