Investigation of influences of mechanical activation and heating rate on nanostructured NiAl-Al2O3 composites formation by combustion synthesis Abstract The paper investigates influence of mechanical activation and heating rate (20°C/min and 40°C/min) on reactions occurrence in combustion synthesis process of nanostructured NiAl-Al2O3 composites by heating of Ni, NiO and Al powder mixture from 20°C to 1300°C. To study reactions occurrence, differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized. By heating the sample without mechanical activation, exothermic reaction of NiO reduction by Al and Ni-Al intermetallic phases production happened in the presence of molten Al; while mechanical activation caused occurrence of these reactions at lower temperatures and separately. By decrement in heating rate, reactions happened separately at lower temperatures. A mechanism for reactions occurrence during heating of mechanically activated sample is proposed. Keywords Composite, Nanostructured Materials, Combustion Synthesis, NiAl, Al2O3, Mechanical Activation, Mechanical Milling, Heating Rate
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