Improved thermal properties of Al powders coated with submicron-sized hollow nickel particles

This work investigates the coating of nano- to submicron-sized hollow nickel particles onto Al powders to optimize the thermal and combustion properties of Al-based energetic materials. Different wt% of hollow nickel particles coated onto Al particles was synthesized using an autocatalytic aqueous reduction method. X-ray diffraction results showed distinct crystalline Al and Ni phases indicating that a pure coating process was achieved. Homogeneous coating of hollow nickel particles onto individual Al particles was also reflected from the scanning electron microscope images. All the samples showed significant improvements in terms of their ignition and kinetics of combustion as compared to untreated Al. The most promising candidate produced was the 30wt%Ni–Al sample whereby the %complete combustion of Al exhibited the largest improvement. The hollow Ni-coated Al samples were also found to perform better than their physically mixed Ni–Al powder samples, as there is more intimate contact between the two components to hasten the overall combustion kinetics.