On The Polarisation And Mott-Schottky Characteristics Of An Fe-Mn-Al-Ni Shape-Memory Alloy And Pure Fe In Nacl-Free And Nacl-Contaminated Ca(Oh)(2,Sat) Solution-A Comparative Study

The polarisation behaviour of both the shape-memory alloy Fe-34Mn-17Al-5Ni and pure Fe were analysed in NaCl-free and NaCl-contaminated Ca(OH)(2,sat) solutions. Simultaneously to the polarisation scan, corrosion progression at the interfaces was studied in-situ and correlated to the applied over-potentials. In NaCl-free Ca (OH)(2,sat), FeMnAlNi and Fe behave similarly, and are characterised by pronounced passivity at low over potentials and intensive O-2 evolution at high overpotentials. In NaCl-contaminated Ca(OH)(2,sat), FeMnAlNi exhibits more severe pitting corrosion sensitivity than Fe. The pitting behaviour is rationalised based on the different semiconducting properties of the passive oxides, which were analysed by the Mott-Schottky technique.