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The role of microexplosions in flame spray synthesis for homogeneous nanopowders from low‐cost metal precursors
Author(s) -
Rosebrock Christopher D.,
Wriedt Thomas,
Mädler Lutz,
Wegner Karsten
Publication year - 2016
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.15056
Subject(s) - combustion , materials science , pyrolysis , evaporation , yield (engineering) , chemical engineering , raw material , metal , homogeneous , slurry , nanoparticle , thermogravimetric analysis , thermal spraying , micrometer , nanotechnology , organic chemistry , metallurgy , chemistry , composite material , coating , mechanical engineering , physics , engineering , thermodynamics
One of the most versatile and rapid manufacturing processes for a variety of nanopowders is flame spray pyrolysis (FSP). The production costs of this scalable process are largely controlled by the raw materials, pushing for the utilization of low‐cost metal precursors. These, however, typically yield inhomogeneous products containing large particles up to micrometer size along with fine nanoparticles. Here, the release mechanism of nitrate and carboxylate precursors from spray droplets has been investigated by single‐droplet combustion experiments and thermogravimetric analysis. The results show that neither precursor evaporation nor choice of solvents is prerequisite for homogeneous nanopowders but droplet microexplosions with continuing combustion. It is shown that even low‐cost metal nitrates yield homogeneous nanopowders if precursors are formulated such that droplet microexplosions occur by internal superheating. The proposed precursor release mechanisms are verified with lab‐ and pilot‐scale FSP, demonstrating that single‐droplet combustion experiments can be employed to predict the product quality. © 2015 American Institute of Chemical Engineers AIChE J , 62: 381–391, 2016