Accession Number : ADA115114

Title :   Impedance Measurement for the Analysis of Corrosion Induced Failures.

Descriptive Note : Final rept. 30 Sep 80-29 Sep 81,


Personal Author(s) : Mansfeld,Florian B ; Kendig,Martin W

PDF Url : ADA115114

Report Date : Feb 1982

Pagination or Media Count : 55

Abstract : Electrochemical techniques for predicting stress corrosion cracking (SCC) susceptibility have been evaluated and constant extension rate tests (CERT) have been performed for a C-Mn Steel (C1117) in 1 M Na3P04, pH=4, T=21 C and in 1.0 M NaHC03/0.1 M Na2C03, T=70 C at controlled potentials with continuous recording of the a.c. impedance in a frequency range between 10 kHz and 30 mHz. These tests have been carried out in potential regions of susceptibility to SCC which were determined by comparing fast and slow anodic potentio-dynamic polarization curves as suggested by Parkins and by analysis of a.c. impedance data as suggested by Armstrong. The occurrence of a high frequency relaxation phenomenon at the potential region where maximum susceptibility to SCC is observed seems to indicate that impedance spectra can be used to assess the SCC behavior. A model for the surface reactions occurring during CERT and the resulting impedance behavior is discussed. (Author)

Descriptors :   *Failure(Mechanics), *Stress corrosion, *Steel, *Aluminum alloys, *Electrochemistry, Mechanical properties, Corrosion inhibition, Impedance, Polarization, High frequency, Relaxation, Surface reactions, Stress strain relations, Electrolytes, Experimental data

Subject Categories : Physical Chemistry
      Test Facilities, Equipment and Methods
      Life Support Systems

Distribution Statement : APPROVED FOR PUBLIC RELEASE