Combustion synthesis of NiAl/Al2O3 composites by induction heating

Combustion synthesis of NiAl requires the combustion reaction to be ignited and fully controlled to maintain the geometry of the compressed parts. This paper describes a new ignition process using induction heating and investigates the effect of Al 2 O 3 on both the combustion synthesis process and the performance of the synthesized products. A high frequency induction heater was used to ignite the synthesis reaction. During synthesis the temperature profiles were measured with infrared thermometers to monitor the reaction process and X-ray Diffraction was used to investigate the phase transformation. The results show that single phase NiAl can be produced by this new process regardless of the addition of Al 2 O 3 . However, the addition of Al 2 O 3 was found to have a significant effect on heating rates, combustion behaviour and properties of the synthesized products. Additionally, there is a critical concentration for Al 2 O 3 above which the compacts cannot be ignited by induction heating. Mechanical properties of the products were tested to evaluate the performance of the synthesized composites.