Dependence of burning rate on sample size in the Ni + Al system

Burning rates were measured for samples of the starting mixture of Ni + Al and the same mixture subjected to mechanical treatment in argon and then in water. The dependences of the burning rate on the diameter of the samples of the original and mechanically activated mixtures are similar. The burning rate passes through a maximum as the diameter increases from 8 to 12 mm. It is found that the burning rate of 270–360 m m thick films obtained by rolling the starting mixture of Ni + Al and the mixture mechanically activated and then activated in water (dispersed) is 4–20 times the burning rate of cylindrical samples 8–12 mm in diameter, pressed from the same powders. The data obtained in this study were explained using a convective-conductive model of combustion-wave propagation.