Dynamical effects of the oxide layer in aluminum nanoenergetic materials

2019-10-02 14:55:19

layer materials oxide pulses thicker

责任者: Wang, Shufeng;Yang, Yanqiang;Yu, Hyunung;Dlott, Dana D. 单位: School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States 来源出处: Propellants, Explosives, Pyrotechnics,2005,30(2):148-155 摘要: Dynamical effects of the aluminum nanopowder oxide layer are investigated in nanoenergetic materials consisting of nitrocellulose (NC) oxidizer containing embedded [similar to] 60nm diameter Al having thinner (2.5 nm) or thicker (6 nm) oxide layers. Following laser flash-heating, a hot spot is formed near each Al particle. The mean distance of reaction propagation drxn from the hot spot through the nitrocellulose is determined with [similar to] 100 nm resolution. With 100 ps pulses a shock propagation mechanism is dominant, and with 10-25 ns pulses reaction a thermal explosion mechanism is dominant. When higher energy picosecond pulses are used, drxn is observed to be significantly increased with thicker oxide layers, but using nanosecond pulses drxn is slightly decreased with thicker oxide layers. This oxide layer enhancement of drxn with picosecond pulses is attributed to the thicker oxide layer confining the hot Al for several tens of picoseconds, resulting in a larger shock wave. This work supports the view of the oxide layer as deadweight for slower heating rate processes such as combustion, but it suggests a thicker oxide layer may be of some benefit for extremely high heating rate processes involved in detonation or high speed deflagration of nanoenergetic materials. © 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim. 关键词: Oxides;Aluminum;Explosives;Thermal effects;Nanostructured materials;Shock waves;Laser theory;Detonation;Combustion;Heating;Nanoenergetic materials;Aluminum nanopowder;Laser flash-heating;Oxide layers