The Effect of the Cobalt Content and Mechanical Activation on Combustion in the Ni + Al + Co System

The effect of mechanical activation (MA) and the cobalt content on the combustion velocity, maximum combustion temperature, elongation of samples during synthesis, the size of composite particles of the mixture after MA, phase composition, and morphology of combustion products in the Ni + Al + Co system is studied. Activation of the Ni + Al + xCo mixture allowed the samples to burn at room temperature, with a cobalt content of up to 50 wt %. An increase in the cobalt content in the Ni + Al + xCo mixtures led to a decrease in the size of composite particles after MA, elongation of product samples, and the maximum synthesis temperature. After MA, the elongation of the product samples and combustion velocity increased many times, and the maximum synthesis temperature increased. With an increase in the cobalt content in the Ni + Al + Co mixture, the combustion velocity first increases (at Co content of 10%), then decreases. Solid solutions based on NiAl and Ni₃Al intermetallic compounds are synthesized by the self-propagating high-temperature synthesis (SHS) method.