Effect of Sintering Temperature on the Pitting Corrosion of Ball Milled Duplex Stainless Steel by using Linear Sweep Voltammetry

The nanostructured duplex stainless steel powders were prepared by specially designed dual drive planetary mill and their microstructural studies were carried out by using scanning electron microscope (SEM) and X-ray diffraction (XRD). The fabricated duplex stainless steels were consolidated by pressureless sintering method at 1100, 1200 and 1300 ˚C respectively at a load of 700MPa. Density, microhardness, microstructure and pitting corrosion of all the sintered duplex stainless steel samples were studied. The corrosion studies were carried out at 0.5, 1 and 2 M concentration of NaCl solution at different quiet time of 2, 6 and 10 seconds by linear sweep voltammetry (LSV) method. Duplex stainless steel samples sintered at 1300 ˚C shows better pitting corrosion resistance than the stainless steel samples consolidated at 1100 and 1200 ˚C. This is due to the improved densification with increase in sintering temperature. The microstructure of corroded duplex stainless steel samples were studied by using field emission scanning electron microscope (FESEM) and optical microscope.