EFFECT OF AGEING ON THE HEAT OF EXPLOSION OF HMX-BASED COMPOPSITIONS CONTAINING NANO-SIZED ALUMINIUM

摘要

The heat of explosion was measured for the HMX-based compositions containing the Al nanopowdes. The Al powders differed in a particle size. Furthermore the surface of nanoaluminium particles was covered with different protective layers. We investigated both the mixtures prepared by common mechanical mixing and the nanocomposites with nanoaluminium particles distributed uniformly in HMX matrix. The powders of mechanical mixtures and nanocomposites were stored for eighteen months into non-hermetic vessels under room conditions. Furthermore new mechanical mixtures were prepared on the base of Al nanopowders which had been stored individually. It follows from the results that the heat of explosion of compositions decreases in consequence of their ageing during storage. In the case of prolonged contact of Al and HMX in compositions the heat of explosion decreases to a greater degree than in the case of individual storage of Al nanopowders. By this is meant that a degradation of mixtures occurs due to the interaction between HMX and Al. This process proceeds with the participation of atmospheric gases. A drop in the heat of explosion is more pronounced when the Al particle size is smaller. However the heat of explosion of nanocomposites decreases to a lesser degree in comparison with the heat of explosion of mechanical mixtures. The obtained data allowed us to evaluate the acceleration ability of the considered compositions in M-40 (steel-plate acceleration from the end of a charge).