Porous Ni–Ti ignition and combustion synthesis

The self-propagating high-temperature synthesis of Ni–Ti mixtures was investigated with particular attention to the ignition step. Ignition was performed using an integrated laser diode system which allows fine control of the heating and ignition processes. The experimental parameters controlling the ignition step such as thermal conductivity, surface absorbance, ignition temperature and energy were obtained both experimentally and by numerical simulation as a function of initial stoichiometry, reactants particle size, and heating cycle. Appropriate ignition conditions were searched in order to minimize the thermal gradients inside the pellet obtaining constant reaction temperature and velocity. Dependencies of reaction front velocity and reaction temperature on the pre-heating one were reported too.