Fabrication of St37 Steel Surface Composites Reinforced by ZrO2 Nano Particles via Friction Stir Processing

Herein, Friction Stir Processing (FSP) is used to disperse ZrO2 Nanoparticles into a matrix of St37 steel to form reinforced composites. The effect of Nanoparticles on microstructural modification and corrosion resistance of FSPed St37 is studied. The microstructural analysis is carried out by using optical and electron microscopes. It is observed that reinforcements are well dispersed inside the nugget zone (NZ), and remarkable grain refinement is achieved. Composite corrosion resistance is evaluated and compared with the Base Metal (BM). The maximum hardness is achieved for ZrO2 composite, whereas a significant increase in pitting resistance of the BM is obtained. The corrosion behavior of the samples is investigated by potentiodynamic polarization tests and assessed in term of pitting potential and passivation range.