International Science and Technology Journal

In order to identify the iron phases and behavior after each treatment in a corroded slab sample, we utilized several techniques such as Mossbauer spectroscopy, thermal analysis, and x-ray diffraction. The ability of the Mossbauer technique in identifying the iron phases and their oxidation state will give some clues on the history of the formation of such iron phases. The Mossbauer results indicate that the main present in the original sample at room temperature are Fe⁺³ with parameters: δ=0.31mm/s, ΔE_Q=0.58mm/s, and Fe₃O₄ with parameters: δ=0.26mm/s, ΔE_Q=0.08mm/s, and H=49.1T. In addition, the Mossbauer spectrum of the sample indicates the presence of a wide range of particle size distribution with average magnetic field H=29.6T. Using thermal analysis we could locate three regions where phase changes took place, the location of these regions are at 300°C, 500°C, and 720°C respectively in addition to a weight loss, these valuable information were used later on during the calcination process. Even though we tried different elevated temperatures for reduction in hydrogen, and longer time, we failed to reduce the sample completely into &alpha-Fe. We expect the reason behind this is either due to the particle size distribution where small particle are difficult to be reduced, or probably there is still some traces of oxygen left in the tube.