Study of aluminum-iron oxide composites obtained by die pressing of industrial by-oroducts

In cities in developing countries, several tons of unprocessed aluminum are buried every day. This is because some kinds of aluminum by-products exhibit low recyclability through remelting, as is the case with sawn mechanical chips. Therefore, the purpose of this project was to address the problem of aluminum chip recycling. The technical approach included the development of a reinforced aluminum with mill scale, an iron oxide by-product from the high-temperature rolling of steel. Aluminum chips and mill scale were ground separately and the resulting powders were characterized. Next, the powders were mixed at different percentages of mill scale (0%, 0.5%, 1.0%, and 2.0%), compacted, and sintered in a protective atmosphere. Iron oxide–aluminum composites were characterized by optical and scanning electron microscopy, x-ray diffraction, differential scanning calorimetry, hardness tests, and potentiodynamic polarization tests. The iron oxide particles and aluminum matrix produced a thermite reaction, forming different kinds of interfaces as a function of the quantity of the mill scale. It was found that 0.5% mill scale is the optimal value for addition, because it improves the hardness of the composite from 50.0 ± 2.4 HRF to 99.9 ± 2.5 HRF. The corrosion rate decreased from 496.7 μm/year to 21.0 μm/year