Article

Short Communications
2016. V. 54. № 6. P. 902–904
Gurentsov E.V., Eremin A.V., Mikheyeva E.Yu., Musikhin S.A.
Anomalous behavior of optical density of iron nanoparticles heated behind shock waves
Annotation
Nonmonotonous variation of the optical properties of iron nanoparticles with a temperature increase during heating behind reflected shock waves is discovered. Iron nanoparticles, within $12$ nm in size, were formed at $0.5$–$1\%\,\rm Fe(CO)_5$ pyrolysis in argon behind the incident shock waves. Using a laser extinction method, a variation of the volume fraction of the condensed phase was registered at the main wavelength of $633$ nm and, in several experiments, at the additional wavelengths of $405$, $520$, and $850$ nm. At the second heating of the produced nanoparticles behind the reflected shock waves within the temperature range $800$–$1500$ K, the function of the complex refractive index, $E(m)$, decreased at all the wavelengths. Within the temperature range of $1500$–$2250$ K, it increased with the temperature increase behind the reflected shock wave almost up to the values that we observed behind the incident shock wave. At the temperatures above $2250$ K, due to the essential evaporation of the iron nanoparticle material, the optical properties were not measured. The iron nanoparticle $E(m)$ variations within the temperature range $800$–$2250$ K are possibly related to their structure variations.
Article reference:
Gurentsov E.V., Eremin A.V., Mikheyeva E.Yu., Musikhin S.A. Anomalous behavior of optical density of iron nanoparticles heated behind shock waves, High Temp., 2016. V. 54. № 6. P. 902