Nanoaluminum particles

Figure 22 shows the time dependence of NO2 disappearance in a flash-heated nanoaluminum sample [201]. NO2 disappearance is measured using CARS spectroscopy to monitor the ONO2 totally symmetric stretching transition near 1300 cm . At the lowest fluence there is practically no NO2 consumption, but at higher fluences, NO2 consumption is seen to occur in two phases. The faster phase is characterized by an -300 ps time constant, and the amplitude of the faster phase increases with laser intensity. The slower phase occurs over -2 ns. The faster phase is associated with consumption of the shell of NO2 near each nanoaluminum particle. The slower phase is associated with NO2 consumption between the hot spots. 

Fig. 22. CARS measurements of nitro consumption by hot nanoaluminum particles in NC. The faster -300 ps phase is identified with nitro consumption in a shell surrounding hot nanoaluminum. The slower -2 ns phase is identified with nitro consumption in the NC between the nanoparticles. Reproduced from ref. [201].

Figure 2. Two fused nanoaluminum particles revealing a grain boundary and...

Figure 3. Oxide coating on nanoaluminum particle revealing exfoliation of aluminum hydroxide surface single molecular laminar sheets...

Finally Figure 5 shows the image of a dislocation found inside a nanoaluminum particle. The presence of dislocations appears rare. 

Figure 20 [201] shows optical emission spectra from nanoaluminum/NC samples as a function of laser fluence. The lowest fluence J = 0.4 J/cm is just enough to melt the A1 particles, and the highest fluence J = 5.2 J/cm is just enough to totally vaporize the particles. The first observable light emission is detected near the melting point. It is broad and structureless and is consistent with a blackbody t5q)e emission. At fluences where the A1 starts to vaporize, a... 

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