Critical Pitting Temperatures in Sodium Chloride and Ferric Chloride Solutions - Determined Using the 'Avesta Cell'

摘要

CPTs obtained using standard practices involving either 6% wt. FeCl_3 or 1 M NaCl are compared. The 'Avesta Cell Method' was employed involving potentiostatic control and simultaneous current measurement during a temperature scan. CPTs for three stainless steels (316, 2205 and 254 SMO~®) were determined using several modifications of the two base electrolytes. Exposure in 1M NaCl solution at an externally controlled potential of +700 mV(SCE) was found to provide conditions as aggressive as exposure at the free corrosion potential in a 6% FeCl_3 solution.