Critical Pitting Test Analysis (CPT)


The critical pitting test is defined in ASTM G150-99. This procedure describes the use of CPT testing for stainless steel
samples. This technique is mainly used in commercial and research corrosion labs to obtain relevant information on
crevice propagation and critical pitting temperature of the samples.
At a constant anodic potential, a simultaneous temperature increase is applied at a rate of 1 ºC/min and current is
measured. The temperature at which a rapid increase in current is observed is the critical pitting temperature of the


Pit propagation, pitting resistance and critical pitting temperature for lab testing of SS samples

Application Notes:

  • Critical pitting temperature measurements with pX1000 (Download)
  • Critical Pitting Temperature (CPT) as per ASTM G150 (Download)

Recommended Configuration:

PGSTAT 302N + Px1000 Module – CPT Analyzer


Metrohm’s customized CPT analysis set-up provides fully automated temperature control and real-time plotting for current and temperature signals.