- 12:30 PM
491a

Size Resolved Kinetics of Nickel Nanoparticle Oxidation

Lei Zhou1, A. Rai1, N. Piekiel1, X. Ma2, and Michael Zachariah3. (1) University of Maryland, College Park, MD 20742, (2) University of Maryland-College Park, College Park, MD 20742, (3) University of Maryland and NIST, 2125 Glenn L Martin Hall, College Park, MD 20742

Nano-scaled nickel particles have attracted interest for its potential use as a fuel in energetic materials. In this work, we combined two ion-mobility spectrometry approaches; tandem differential mobility analysis (TDMA) and tandem differential mobility particle mass analysis (DMA-APM) to study the size resolved reactivity of nickel nanoparticles. Nickel nanoparticles were generated in-situ using gas-phase thermal pyrolysis of nickel carbonyl. Four particle sizes (40, 62, 81 and 96 nm, mobility size) were then selected by using a differential mobility analyzer. These particles were sequentially oxidized in a flow reactor at various temperatures (25-1100 C). The size and mass change of the size selected and reacted particles were then measured by a second DMA, or an APM. We found that both particle size and mass were increased as the temperature increased. However, at higher temperature (600-1100C), a different mass and size change behavior was observed which could attribute to a phase transition between NiO and Ni2O3. A shrinking core model employed to extract the size- resolved kinetic parameters shows that the activation energy for oxidation decreased with decreasing particle size The burning time power dependence on particle size was found to be less than 2 and nickel particles were found to be kinetically more active than aluminum.


Web Page: www.enme.umd.edu/~mrz