Linearly concentrating solution favors efficient and precise determination of critical pitting chloride concentration

Abstract

The critical pitting chloride concentration (CPCC) is an essential parameter for the safe service of structural alloys that sensitive to pitting corrosion. Precise lacking and time-consuming frustrates the traditional method (multiple tests), i.e., applies various solutions with different concentrations and then gradually approaches the real CPCC. Herein, a novel method (single test) was proposed to efficiently and precisely positioning CPCC, i.e., linearly increasing chloride concentration that realized by a peristaltic pump with a high precision drip rate of μL/min. Moreover, a non-linear sensitivity of CPCC to concentrating rate of chloride ion was revealed on CoCrFeNiAl_x alloys and the possible mechanism is discussed.