SPIN COMBUSTION IN THE NICKEL-SILICON SYSTEM

The combustion synthesis of five Ni Si phases was investigated. Without preheating, samples corresponding to the initial stoichiometries Ni3Si, Ni5Si2, Ni3Si2, and NiSi sustained a self-propagating combustion mode which advanced in a spin mode. With preheating ( > 500-degrees-C), the sample combusted in a steady-state mode. Average combustion wave velocities and frequencies of spin showed maxima at a composition of 33 at % Si. The combustion temperature showed a maximum at a composition in the range of 33-40 at %. In contrast, the ignition temperature showed a minimum at a composition of 33 at %. X-ray analyses showed that in all cases, the product of combustion was multi-phase with the primary phase corresponding to the initial stoichiometry of the reactant.