TY - JOUR
T1 - The effect of gas phase polydimethylsiloxane surface treatment of metallic aluminum particles
T2 - Surface characterization and flow behavior
AU - Ludwig, Bellamarie
AU - Gray, Jennifer L.
N1 - Funding Information:
This work was supported by the Office of Naval Research under Grant No. N00014-14-1-0692. The authors are grateful to Mrs. Maria Medeiros for securing funding this effort, Shawn Ward for his assistance with fabrication of the fluidized bed reactor, and Josh Maier, who prepared the FIB samples. All opinions, findings, conclusions, and recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of the Office of Naval Research.
Publisher Copyright:
© 2016 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences
PY - 2017/2/1
Y1 - 2017/2/1
N2 - Aluminum particles were exposed to gaseous polydimethylsiloxane (PDMS) to produce a hydrophobic surface coating for enhanced flow and fluidity. Surface retention of the intact PDMS was confirmed through infrared and X-ray photoelectron spectroscopy. Transmission electron microscopy was used to image cross-sections of the treated particles and energy dispersive spectroscopy element maps demonstrated the presence of a surface layer consisting of silicon and oxygen. Density measurements provided evidence for improvements in the Hausner ratio and Carr index of the PDMS-treated aluminum, indicating a reduction in inter-particulate cohesion through increased bulk density. Stability, compressibility, shear, aeration, and permeability of the particles were assessed by powder rheometer. The compressibility was reduced by approximately 32% following surface treatment, revealing a reduction in void space, while Mohr's circle analysis and shear testing determined that the extrapolated cohesion value was reduced by approximately 53% and the flow factor at 6 kPa was doubled. Aeration testing showed that the air velocity required to obtain a fluidized bed was on the order of 0.35 mm/s for the treated powder, whereas the raw powder could not be uniformly fluidized. PDMS may be a viable option for the large-scale treatment of aluminum powder for flow applications.
AB - Aluminum particles were exposed to gaseous polydimethylsiloxane (PDMS) to produce a hydrophobic surface coating for enhanced flow and fluidity. Surface retention of the intact PDMS was confirmed through infrared and X-ray photoelectron spectroscopy. Transmission electron microscopy was used to image cross-sections of the treated particles and energy dispersive spectroscopy element maps demonstrated the presence of a surface layer consisting of silicon and oxygen. Density measurements provided evidence for improvements in the Hausner ratio and Carr index of the PDMS-treated aluminum, indicating a reduction in inter-particulate cohesion through increased bulk density. Stability, compressibility, shear, aeration, and permeability of the particles were assessed by powder rheometer. The compressibility was reduced by approximately 32% following surface treatment, revealing a reduction in void space, while Mohr's circle analysis and shear testing determined that the extrapolated cohesion value was reduced by approximately 53% and the flow factor at 6 kPa was doubled. Aeration testing showed that the air velocity required to obtain a fluidized bed was on the order of 0.35 mm/s for the treated powder, whereas the raw powder could not be uniformly fluidized. PDMS may be a viable option for the large-scale treatment of aluminum powder for flow applications.
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U2 - 10.1016/j.partic.2016.05.010
DO - 10.1016/j.partic.2016.05.010
M3 - Article
AN - SCOPUS:84994454826
SN - 1674-2001
VL - 30
SP - 92
EP - 101
JO - Particuology
JF - Particuology
ER -