Preparation of Fe-8%Ni alloyed powder fabricated by novel recycling process

Fe-8%Ni alloyed powder was fabricated by oxidation and mechanical alloying technique using Fe-36%Ni scrap. Oxidation behavior of Fe-36%Ni alloy was studied in air using thermogravimetric apparatus (TGA), and oxidation rate was shown to be sharply increased after 500 °C. It was found that the alloyed scrap was completely oxidized at 1100 °C for 96 hours. Fe₂O₃ and NiO were observed to be the major phases in oxide scale of the scrap. The scrap completely oxidized was ball-milled to make average particle size of 1.5 μm. The oxide powder was synthesized in wet-ball milling with addition of Fe ₂O₃ powder in order to meet the desire composition. Finally, Fe-8%Ni alloyed powder was obtained after reduction in H₂ gas atmosphere at 650 °C for 5 hours, and the powders were examined by X-ray fluorescence (XRF), X-ray diffraction (XRD), and scanning electron microscopy (SEM).