Ignition and Combustion of Al Particles Clad by Ni
Résumé
Combustion of single nickel-clad aluminum particles suspended (‘‘levitated’’) in different gas environments is investigated. Thermal explosion characteristics of samples compacted from such particles are also studied. It is shown that clad Al=Ni particles can burn not only in oxidizing (O2, CO2, air) but also in inert (Ar) atmospheres, solely owing to gasless metal-metal interaction. Ignition temperature (10501240 K) of clad particles is much lower than for aluminum (2000 K). It is also shown that their combustion mechanisms depend on the nature of ambient atmosphere. Specifically, burning of such particles in air involves two stages, with inverse images of flame (bright core–dark flame and dark core–bright flame).