Ignition time of nanopowders during milling: A novel simulation

Abstract

Detecting the sudden temperature increase of the milling vial, detecting the sudden total pressure increase inside the vial as well as XRD analysis from the synthesized phases are techniques that can be used to determine the ignition time in mechanically self-sustaining reactions (MSRs) induced by ball milling. In the present study a novel technique based on the Gene Expression Programming (GEP) algorithm is presented to estimate the ignition time in MSRs induced by high energy planetary mills, without any experimental testing. In other words, only by knowing some of the milling and reaction parameters comprised of ΔH/CP, ball to powder weight ratio (BPR), vial spinning rate, arithmetic mean of melting points of reactants, average diameter of balls and amount of used process control agent (PCA), one can predict the ignition time in the mentioned systems. Accordingly, most of the systems that are based on the MSR mode were gathered from the literature, and the data obtained from them are trained and tested by the GEP modeling algorithm. The results indicated a very good agreement between the experimental data and the predicted ones. The biogeography based optimization (BBO) was also utilized to optimize the milling parameters. Experiments were performed at the optimized parameters to proof the validity of the analysis. Given the broad range of the parameters used, it was found that our analysis and model are fully functional to accurately estimate the optimal conditions for planetary mills experiments which show the potential application of these calculations and analysis in materials science and engineering.