Effect of Ni content on the reaction behaviors of self-propagating high-temperature synthesis in the Ni-Ti-B4C system

Reaction behaviors of self-propagating high-temperature synthesis (SHS) in the Ni-Ti-B4C systems with various Ni contents were investigated. The addition of Ni supports the initiation of ignition. Theoretical calculation of the adiabatic temperatures reveals that the reactions in the Ni-Ti-B4C systems are self-sustainable for the presence of 0-66.4 wt% Ni in the reactants without any preheat. The Ni content plays a significant role in controlling reaction behavior and the constituents of the final products, but can not affect the ignition process greatly. With the increase of Ni content, combustion temperatures, wave velocities and ceramic particle sizes decrease, while the ignition time shows first a remarkable decrease and then an increase with the minimum value at 20 wt% Ni.