Thermal explosion in Ni-Al system: influence of reaction medium microstructure
Thermal explosion in Ni-Al system: influence of reaction medium microstructure
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DOI：
10.1016/s0010-2180(02)00402-9
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发表时间：
2002-10
影响因子：
4.4
通讯作者：
L. Thiers;A. Mukasyan;A. Varma
中科院分区：
文献类型：
--
作者：
L. Thiers;A. Mukasyan;A. Varma
研究了不同反应物介质显微结构的Al-Ni体系（富al成分）的热爆炸现象。比较了Ni包覆Al颗粒与不同粒径Al+Ni粉末混合物的TE参数（如着火温度、反应时间等）。研究了升温速率在100 ~ 900 K/min范围内对TE特性的影响。结果表明，点火过程既与相（反应物或第一产物的熔化）转变有关，也与微观结构（包层颗粒时Ni壳的破裂）转变有关，并取决于反应物介质的微观结构。后者影响初始产物的形成过程，进而影响点燃后阶段的相互作用速率。对所得结果进行了讨论，并与文献报道的结果进行了比较。一般来说，我们认为非均质无气系统中的爆炸与常规均质介质中的爆炸不同。在后者中，工作条件决定了点火温度，而在前者中，它与系统相图有关，因此是系统的特征性质。
The thermal explosion (TE) phenomenon was investigated in the Al-Ni system (Al-rich compositions) with various reactant medium microstructures. The parameters of TE (e.g., ignition temperature, reaction times, etc.) obtained for Al particles clad by Ni were compared with those for Al+Ni powder mixtures having different particle sizes. The heating rate was varied in the range 100 to 900 K/min, and its influence on TE characteristics was also studied. The results show that ignition process is related to either phase (melting of reactant or first product formed) or microstructural (breaking of the Ni shell in case of clad particles) transformations and depends on the reactant medium microstructure. The latter influences the process of initial product formation, which in turn affects the interaction rate during the post-ignition stages. The obtained results were discussed and compared with those reported in the literature. In general, it is suggested that TE in heterogeneous gasless systems differs from explosions in conventional homogeneous media. In the latter, the operating conditions define ignition temperature, while in the former, it is related to the system phase diagram and thus is a characteristic property of the system.