| 1. |
- Aromaa, Mikko, et al.
(författare)
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Atmospheric synthesis of superhydrophobic TiO2 nanoparticle deposits in a single step using Liquid Flame Spray
- 2012
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Ingår i: Journal of Aerosol Science. - : Elsevier BV. - 0021-8502. ; 52, s. 57-68
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Tidskriftsartikel (refereegranskat)abstract
- Titanium dioxide nanoparticles are synthesised in aerosol phase using the Liquid Flame Spray method. The particles are deposited in-situ on paperboard, glass and metal surfaces. According to literature, titanium dioxide is supposed to be hydrophilic. However, hydrophobic behaviour is observed on paperboard substrates but not on metal or glass substrates. Here, the water contact angle behaviour of the deposits is studied along with XRD, XPS, BET and HR-TEM. The deposits are compared with silicon dioxide deposits having, as expected, hydrophilic properties synthesised with the same method. It seems probable that the deposition process combusts some substrate material from the paperboard substrate, which later on condenses on top of the deposit to form a carbonaceous layer causing the hydrophobic behaviour of the TiO2 deposit. The similar layer does not form when depositing the nanoparticles on a metal or glass surfaces. The observations are more than purely aerosol phenomena. However, they are quite essential in nanoparticle deposition from the aerosol phase onto a substrate which is commonly utilised. (C) 2012 Elsevier Ltd. All rights reserved.
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| 2. |
- Nikkanen, Juha-Pekka, et al.
(författare)
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Synthesis of carbon nanotubes on FexOy doped Al2O3-ZrO2 nanopowder
- 2014
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910. ; 266, s. 106-112
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Tidskriftsartikel (refereegranskat)abstract
- Carbon nanotubes (CNTs) were synthesized on liquid flame sprayed (LFS) powder substrate of iron oxide doped Al2O3-ZrO2. Iron oxide doped Al2O3-ZrO2 nanopowder was produced by injecting the liquid precursor of aluminium-isopropoxide, zirconium-n-propoxide, ferrocene and p-xylene into a high temperature (similar to 3000 K) flame. The precursor solution was atomized by high-velocity H-2 flow and injected into the flame where nanopartides were formed. The collected sample was used as a substrate material for the synthesis of CNTs. The CNTs were formed on the surfaces of the substrate powder by catalyzed decomposition of CH4. The particle morphology, size, phase composition and the nature of CNTs were determined by TEM, FE-SEM, XRD, XPS, Mossbauer and Raman spectroscopy. The collected powder consists of micron-sized agglomerates with nanosized primary particles. Tetragonal zirconia was detected while alumina was amorphous. In the carbonized sample multiwalled CNTs were obtained. (C) 2014 Elsevier B.V. All rights reserved.
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| 3. |
- Saarimaa, Ville J., et al.
(författare)
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Assessment of pitting corrosion in bare and passivated (wet scCO2-induced patination and chemical passivation) hot-dip galvanized steel samples with SVET, FTIR, and SEM (EDS)
- 2020
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Ingår i: Materials and corrosion - Werkstoffe und Korrosion. - : Wiley-VCH Verlag. - 0947-5117 .- 1521-4176.
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the local electrochemical activity of untreated and passivated (natural or chemical passivation) zinc specimens was observed during immersion in a 0.1-M NaCl solution. The localized anodic activity during the exposure, measured with the scanning vibrating electrode technique, was linked to zinc dissolution by the pitting corrosion mechanism. It was correlated to specific corrosion products characterized by Fourier transmission infrared (FTIR) microscopy. FTIR molecule maps were produced from individual pitting corrosion sites (100–200 µm in width). With argon ion beam milling and latest energy-dispersive X-ray spectroscopy (EDS) technology, element maps with a high spatial resolution (≪100 nm) were recorded from abrasion- and beam-sensitive corrosion products, showing a residual layer structure. This study demonstrates the capability of FTIR mapping, cross-section polishing, and state-of-the-art scanning electron microscopy imaging, and EDS element mapping to produce high-resolution elemental, molecular, and visual information about pitting corrosion mechanisms on a hot-dip galvanized steel sample.
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