|
2201 |
|
Corrosion behavior of thermally sprayed high entropy stainless steel coatings before and after heat treatments
|
|
Angeliki Lekatou / Department of Materials Science & Engineering, University of Ioannina, Greece Dimitrios Zois / University of Ioannina, Dept Mater Sci & Engng, Greece Michael Vardavoulias/ Pyrogenesis SA, Greece Tiverios Vaimakis/ University of Ioannina, Department of Chemistry, Greece |
|
A commercial semi-crystalline Fe-based powder has been sprayed by HVOF to produce coatings of high amorphicity on stainless steel substrates. Optimization of the spray conditions led to coatings of good uniformity, low porosity and high adhesion strength. The coatings presented lower crystallinity than the initial powder. The corrosion resistance and the susceptibility to localized corrosion of the deposited coatings in 3.5% NaCl were examined by cyclic potentiodynamic polarization, potentiostatic polarization and Raman spectroscopy. Upon cyclic polarization, all the coatings showed pseudopassivity in 3.5% NaCl. They were susceptible to localized corrosion; nevertheless they repassivated. The effect of amorphicity on the corrosion behaviour of the coatings was analytically investigated by subjecting the coatings to isothermal heat treatments at a series of temperatures in the recovery and recrystallization range . The heat treating temperatures were selected by employing DSC (Differential Scanning Calorimetry) and XRD (X- Ray Diffraction). The corrosion properties of the heat treated coatings were electrochemically examined and discussed in terms of stress relief, recrystallization and precipitation processes. |