Hooley, R orcid.org/0000-0002-3515-4195, Brown, A orcid.org/0000-0001-9692-2154 and Drummond-Brydson, R orcid.org/0000-0003-2003-7612 (2019) Factors affecting electron beam damage in calcite nanoparticles. Micron, 120. pp. 25-34. ISSN 0968-4328
Abstract
We report electron fluence thresholds for the degradation of calcite nanoparticles under electron irradiation by both conventional and scanning TEM (CTEM and STEM), using time resolved phase contrast imaging and EDX spectroscopy at both 80 kV and 300 kV accelerating voltages. We show that the degradation pathway of calcite involves disruption of the crystal lattice with the evolution of pores and transformation to calcium oxide and carbon dioxide. Depending on irradiation conditions (CTEM or STEM), the calcium oxide formed can be either amorphous or crystalline, with the formation of the latter apparently being hindered by hydrocarbon contamination build up in STEM. For a given electron flux, irradiation at 300 kV prolongs the characteristic lifetime of the calcite lattice as compared to irradiation at 80 kV but with a corresponding reduction in both image contrast and energy dispersive X-ray (EDX) signal, consistent with the change in inelastic mean free path for electron scattering. STEM offers significant benefits over CTEM, however only in the presence of hydrocarbon contamination, increasing the fluence threshold for the detection of irradiation induced faults in the calcite lattice from 2.7x10^7 e-nm-2 for 300 kV CTEM to over 1.8x10^8 e-nm-2 for 300 kV STEM. This work forms a framework for reliable identification of discrete particle crystallinity in nominally amorphous, nanoscale calcium carbonate particles which is of importance for fundamental studies of crystallisation and also for the process control during the synthesis of such surfactant stabilised nanoparticles for application as over-based fuel detergents.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | (c) 2018, Elsevier Ltd. All rights reserved. This is an author produced version of a paper published in Micron. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | electron beam damage; phase contrast; calcium carbonate; STEM; hydrocarbon contamination |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Funding Information: | Funder Grant number EPSRC EP/M028143/1 EPSRC EP/R018820/1 EPSRC EP/R02863X/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 29 Jan 2019 12:30 |
Last Modified: | 29 Jan 2020 01:38 |
Status: | Published |
Publisher: | Elsevier Ltd. |
Identification Number: | 10.1016/j.micron.2019.01.011 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:141695 |