Flame spray pyrolysis synthesis and aerosol deposition of nanoparticle films

Authors

  • Antonio Tricoli,

    Corresponding author
    1. Dept. of Mechanical and Process Engineering, Particle Technology Laboratory, ETH Zurich, CH-8092, Zurich, Switzerland
    • Dept. of Mechanical and Process Engineering, Particle Technology Laboratory, ETH Zurich, CH-8092, Zurich, Switzerland
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  • Tobias D. Elmøe

    1. Dept. of Chemical and Biochemical Engineering, Technical University of Denmark, DK-2800 Lyngby, Denmark
    Current affiliation:
    1. Amminex A/S, DK-2860 Soeborg, Denmark
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Abstract

The assembly of nanoparticle films by flame spray pyrolysis (FSP) synthesis and deposition on temperature-controlled substrates (323–723 K) was investigated for several application-relevant conditions. An exemplary SnO2 nanoparticle aerosol was generated by FSP and its properties (e.g., particle size distribution), and deposition dynamics were studied in details aiming to a simple correlation between process settings and film growth rate. At high precursor concentrations (0.05–0.5·mol/L), typically used for FSP synthesis, the nanoparticles agglomerated rapidly in the aerosol leading to large (>100 nm) fractal-like structures with low diffusivity. As a result, thermophoresis was confirmed as the dominant nanoparticle deposition mechanism down to small (≈40 K) temperature differences (ΔT) between the aerosol and the substrate surface. For moderate-high ΔT (>120 K), thermal equilibrium was rapidly obtained yielding a constant thermophoretic flux and film growth rate. A model was developed to predict the nanoparticle deposition rates by FSP synthesis at moderate-high ΔT that does not require detailed analysis of the aerosol composition. Comparison with previous studies having similar nozzle geometries showed that the deposition rates of FSP-made aerosols can be reasonably well predicted for various materials and flame conditions. © 2012 American Institute of Chemical Engineers AIChE J, 2012

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