Project Details
Projekt
Insitu study of particle formation and particle growth in the flame spray pyrolysis by means of the small angle X-ray scattering technique
Applicant
Professor Dr.-Ing. Hermann Nirschl
Subject Area
Mechanical Process Engineering
Term
since 2017
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 374851568
The production of nanoparticles using flame spray pyrolysis (FSP) is characterized by a complex particle formation mechanism within a few milliseconds. Therefore, a detailed description of particle nucleation and growth is of great interest to control the process. The aim of the SPP is to research the entire process chain from spray generation and evaporation to particle formation and agglomeration during the flame synthesis in an interdisciplinary network. This project focuses on the acquisition of particle sizes using small angle X-ray scattering (SAXS) as an insitu measurement technique to describe the particle and agglomerate formation processes in and above the flame.In the first funding period, an extensive SAXS characterization of the products (iron oxide) of the FSP was performed using the standard precursor (iron nitrate nonahydrate in 65% ethylhexanoic acid and 35% ethanol). The polydisperse particle structures are probably caused by two parallel particle formation mechanisms. To perform insitu measurements, the SpraySyn burner was integrated into a laboratory SAXS-camera. Additionally, particles were extracted from and above the flame using a hole-in-tube system. Although a detection of particle growth in and directly above the flame was not possible, a shift towards larger particles was observed in comparison to the final product. The experimental setup could be used without major changes for the insitu measurements at the synchrotron. With increasing height above the burner, the measured scattering intensity also increased pointing to the formation of new particles. During the first funding period, a successful and detailed characterization of the products as well as the commissioning of the burner and its transfer to the synchrotron was achieved. In the second funding period, the insitu knowledge of particle structures will be used to select suitable new precursors for new particle compositions which show high scattering properties in and above the flame. At the same time the automation of the setup at the synchrotron is scheduled to improve the results of the insitu measurement results.In addition to insitu measurements, detailed exsitu analyses are planned at the synchrotron using X-ray diffraction and absorption spectroscopy as well as with partners of the SPP. The aim is to develop a mechanism for the description of particle formation based on the in-situ SAXS results using the SpraySyn burner.
DFG Programme
Priority Programmes
