Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group

In situ light-scattering measurements of morphologically evolving flame-synthesized oxide nanoaggregates

Not Accessible

Your library or personal account may give you access

Abstract

Nonspherical Al2O3 aggregates produced in a laminar counterflow nonpremixed methane flame were investigated with an in situ laser light-scattering (LLS) technique in combination with a thermophoretic sampling–transmission electron microscope (TS–TEM) method. These flame-synthesized nanoparticles clearly underwent morphological changes following their formation (from precursor trimethylaluminum hydrolysis), mainly as a result of aggregation and sintering processes in the ∼3.3 × 104 K/s heating environment. To characterize this particulate morphological evolution conveniently we made multiangular absolute LLS measurements and interpreted them based on the Rayleigh–Debye–Gans scattering theory for fractal aggregates. Optically determined fractal dimension D f, mean radius of gyration, aggregate size distribution, and local particle volume fraction ϕp were found to be consistent with our independent ex situ TS–TEM experiments. D f (optically inferred) increased from 1.60 to 1.84 with axial position, confirming the morphological evolution of alumina aggregates owing to finite-rate, spatially resolved high-temperature sintering. An extension of our TS–TEM method was successfully applied, for the first time to our knowledge, to inorganic particles. ϕp inferred by means of this ex situ technique generally agreed with that from the in situ LLS technique, supporting our interpretation of both measurements. Moreover, an optically inferred net sintering rate of alumina aggregates approaching the flame was estimated to be consistent with the available TEM data. The LLS methods and results presented here are expected to permit more comprehensive mechanistic analyses of nanoaggregate sintering and coagulation kinetics in such flame environments, ultimately improving the modeling of more-complex (e.g., turbulent, high-pressure) combustion systems involving nanoparticle formation and evolution.

© 1999 Optical Society of America

Full Article  |  PDF Article
More Like This
Dynamic light scattering and angular dissymmetry for the in situ measurement of silicon dioxide particle synthesis in flames

Michael R. Zachariah, D. Chin, H. G. Semerjian, and J. L. Katz
Appl. Opt. 28(3) 530-536 (1989)

Determination of soot parameters by a two-angle scattering–extinction technique in an ethylene diffusion flame

Silvana De Iuliis, Francesco Cignoli, Sergio Benecchi, and Giorgio Zizak
Appl. Opt. 37(33) 7865-7874 (1998)

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Figures (10)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Tables (1)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Equations (12)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an Optica member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access Optica Member Subscription

Select as filters


Select Topics Cancel
© Copyright 2024 | Optica Publishing Group. All Rights Reserved