Short Communication

Preliminary measurements are presented for the lean limits of flammability (minimum explosible concentrations) for several meta) dusts dispersed in air. The metals were selected to include a wide range of maximum adiabatic flame temperatures and an even wider range of volatilities or vapor pressures at those temperatures. The results are analyzed in terms of alternative flame propagation mechanisms: a homogeneous one involving gas phase reactions of metal vapors, or a heterogeneous one involving surface phase oxidation of the solid or liquid metal particulates.