Effect of the Initial Temperature on the Modes of Passivation of Pyrophoric Powders: Macrokinetic Approach

Resumo

The thermal modes of passivation of pyrophoric nanopowders at a reduced initial temperature of a nanopowder bed were studied by analytical and numerical methods using a macrokinetic approach. It was shown that a decrease in the initial temperature of a nanopowder leads to a transition from the layer-by-layer passivation mode to the bulk passivation mode, which makes it possible to control the acceptable warmup level in passivation even if the oxidizer concentration in the gas is high. Analytical expressions for determining the boundaries of the layer-by-layer and bulk passivation modes were derived and confirmed by numerical calculations.