Description
This thesis investigates the Thermal Explosion Combustion synthesis processing of Nickel aluminide (Ni3Al) -carbon nanotube (CNT) nanocomposites. The effect of initial Nickel (Ni) particle size on the mechanical milling time of Ni-CNT composite powder was investigated in terms of its effect on dislocation density, crystal size, micro-strains and composite particle size distribution. Ni-CNT/Al milled powder was then combustion synthesized under the effect of electric current. With the increase in mechanical milling time the ignition temperature and ignition time for the two investigated initial Nickel particle sizes (4-8μm and 45-90μm) was seen to be decreasing. The smaller initial Nickel particle size samples resulted in better homogeneity in the reacted sample and less porosity when compared to larger initial Nickel particle size samples. Moreover, the longer milling time resulted in an increase in homogeneity. The major phase was determined to be Ni3Al. Also, increase in milling time increases the hardness of the final microstructure with smaller initial Nickel particle samples having higher harness compared to larger initial particle Nickel samples.
