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Title: Characterisation of metakaolin-based geopolymers using beam-based and conventional PALS.
Authors: Guagliardo, P
Roberts, J
Vance, ER
Weed, R
Sergeant, AD
Howie, A
Wilkie, P
Went, M
Sullivan, J
Williams, J
Samarin, S
Buckman, S
Keywords: Positrons
Particle beams
Inorganic polymers
Heat treatments
Issue Date: 1-Aug-2010
Publisher: Institute of Physics
Citation: Guagliardo, P., Roberts, J., Vance, E. R., Weed, R., Sergeant, A. D., Howie, A., Wilkie, P., Went, M., Sullivan, J., Williams, J., Samarin, S., Buckman, S. (2010). Characterisation of metakaolin-based geopolymers using beam-based and conventional PALS. 12th International Workshop on Slow Positron Beam Techniques for Solids, Surfaces, Atoms and Molecules (SLOPOS12), 1st - 6th August 2010. All Seasons Resort: Magnetic Island, North Queensland, Australia. In Journal of Physics: Conference Series, 262(1), 012023. doi:10.1088/1742-6596/262/1/012023
Abstract: The nano-porosity of metakaolin-based geopolymers and the effect of heat-treatment on porosity have been studied with conventional and beam-based positron annihilation lifetime spectroscopy (PALS). Conventional PALS found significant nano-porosity in the geopolymers, as indicated by the presence in the PALS spectrum of two long lifetime components, τ3 = 1.58 ns and τ4 = 47 ns, associated with pore diameters of approximately 0.5 and 3 nm respectively. The lifetime of the shorter component was found to decrease monotonically with successive heat treatments of 300°C and 600°C. Beam-based PALS, conducted at 5 keV, also indicated two long lifetime components, τ3 = 4.84 ns and τ4 = 54.6 ns. These are significantly longer than those observed by conventional PALS and the monotonic decrease of τ3 with successive heat treatments was not observed. As the beam-based PALS probed only the near-surface region, with an average implantation depth of about 350 nm, these results suggest that the near-surface structure may vary significantly from that of the bulk. This could be an inherent property of the samples or an artefact caused by surface effects or sample outgassing. © Copyright 2020 IOP Publishing
Gov't Doc #: 3336
ISSN: 1742-6588
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