Current and potential fluctuation characteristics in IGSCC processes of stainless steels

Y. Watanabe, T. Kondo

Research output: Contribution to journalConference article

3 Citations (Scopus)

Abstract

Electrochemical noise behavior of austenitic stainless steels with various degrees of sensitization was investigated under slow-strain-tensile (SSRT) conditions in a dilute sodium thiosulfate solution. Fluctuations both in short-circuit current between a SSRT specimen and a counter electrode under freely corroding potential and in corrosion potential were simultaneously monitored. Current and potential fluctuation behavior was dependent on degree of sensitization. No significant fluctuation was detected from a slightly sensitized sample where no SCC was found and only permanent anodic current was observed from a highly sensitized material after yielding point without any transition behavior. Transition behavior with current pulses and corresponding potential fluctuations was detected from an intermediately sensitized sample. Most pulses were detected after yielding point and the frequency of pulse generation gradually increased as strain was increased and finally changed into permanent current mode. A one to one comparison was made between current pulses and surface damages for an interrupted SSRT specimen and a direct correlation was found between a pulse and a crack initiation event. Current pulses had one to one consistency to a differential of the corresponding potential signals, dE/dt. This indicated that double-layer capacitance took the dominant role for a cathode in the initiation stage of SCC.

Original languageEnglish
JournalNACE - International Corrosion Conference Series
Volume1998-March
Publication statusPublished - 1998 Jan 1
EventCorrosion 1998 - San Diego, United States
Duration: 1998 Mar 221998 Mar 27

Keywords

  • Austenitic stainless steel
  • Current pulse
  • Double-layer capacitance
  • Electrochemical noise
  • Intergranular crack
  • Potential fluctuation
  • Short-circuit current
  • Slow-strain-rate test
  • Stress corrosion cracking

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Science(all)

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