Browsing by Subject "Deposition"

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  • Leskelä, M.; Salmi, E.; Ritala, M. (2017)
    This paper reviews the use of Atomic Layer Deposition (ALD) in protective coatings. Because of the growth principle ALD allows the deposition of dense conformal films on substrates of different size and shape. Recently, ALD has received increasingly interest in deposition of protective coatings. In protective coatings oxides are the most common materials and especially Al, Ti, and Ta oxides have been applied. The use of nanolaminates enables improving the protection properties. Since ALD films are pinhole-free and often thin they are used to protect against moisture, radiation, out-gassing but not often against corrosion of metals. Very good moisture barriers are obtained with thin ALD oxide layers on polymers and cardboard. This property is also very attractive in encapsulation of OLEDs. In studies of energy technology materials protection of electrodes in Li-ion batteries, fuel cells and supercapacitors by ALD has been reported and significant improvement in the stability has been achieved. Yet another area is protection of silver jewelry from tarnishing by a thin oxide layer. In traditional corrosion protection of metals ALD films have proven to be useful in tailoring of interfaces and sealing of defects in coatings made by other techniques. © 2017 Trans Tech Publications, Switzerland.
  • Widdowson, Anna; Coad, Joseph Paul; Alves, Eduardo; Baron-Wiechec, A.; Catarino, Norberto; Corregidor, Victoria; Heinola, Kalle; Krat, Stepan; Makepeace, C.; Matthews, Guy F.; Mayer, Matej; Mizohata, Kenichiro; Sertoli, Marco (2019)
    Post mortem analysis shows that mid and high atomic number metallic impurities are present in deposits on JET plasma facing components with the highest amount of Ni and W, and therefore the largest sink, being found at the top of the inner divertor. Sources are defined as “continuous” or “specific”, in that “continuous” sources arise from ongoing erosion from plasma facing surfaces and “specific” are linked with specific events which decrease over time until they no longer act as a source. This contribution evaluates the sinks and estimates sources, and the balance gives an indication of the dominating processes. Charge exchange neutral erosion is found to be the main source of nickel, whereas erosion of divertor plasma facing components is the main source of tungsten. Specific sources are shown to have little influence over the global mid- and high-Z impurity concentrations in deposits.
  • JET Contributors; Lahtinen, A.; Likonen, J.; Koivuranta, S.; Alves, E.; Baron-Wiechec, A.; Catarino, N.; Coad, J. P.; Heinola, K.; Räisänen, J.; Widdowson, A. (2019)
    Tungsten-coated divertor files exposed during the third JET ITER-Like Wall (ILW) campaign in 2015-2016 (ILW-3) were studied with Secondary Ion Mass Spectrometry (SIMS). ILW-3 campaign contained more high-power plasma discharges and longer plasma time than the earlier ILW campaigns. Measurements showed increased beryllium (Be) deposition on the upper inner divertor, whereas on the outer divertor, Be deposition was lower than during the second campaign in 2013-2014 (ILW-2). Increased intensifies of nickel, molybdenum and tungsten were observed at the surface layer of the inner divertor Be dominated deposits. These layers are probably formed during the high-power plasma discharge phase near the end of the ILW-3 campaign. Compared to the earlier campaigns, D retention on the upper inner divertor was observed to on a similar level than after ILW-2, whereas at the lower inner divertor and most parts of the outer divertor, D retention was lower for ILW-3 than ILW-2. D retention was increased at lower part of outer divertor Tile 7, where Be deposition was slightly increased. Probable reason for the reduction is the higher surface temperature of the files due to higher powers used.
  • Lodenius, M. (Elsevier Science B.V., 1998)
    The dry and wet deposition near a Finnish chlor-alkali plant was estimated by using the moss-bag technique. The estimated net deposition was 130 ng g-1 per month or 480 mg m-2 per year. Two-thirds of the deposition was dry and one-third wet. The results emphasize the importance of the direct uptake of atmospheric mercury by vegetation.
  • Hatano, Y.; Lee, S.E.; Likonen, J.; Koivuranta, S.; Hara, M.; Masuzaki, M.; Asakura, N.; Isobe, K.; Hayashi, T.; Ikonen, J.; Widdowson, A.; EUROfusion Consortium, JET; Ahlgren, Tommy (2019)
    Tritium (T) distributions on tungsten (W)-coated plasma-facing tiles used in the third ITER-like wall campaign (2015-2016) of the Joint European Torus (JET) were examined by means of an imaging plate technique and beta-ray induced x-ray spectrometry, and they were compared with the distributions after the second (2013-2014) campaign. Strong enrichment of T in beryllium (Be) deposition layers was observed after the second campaign. In contrast, T distributions after the third campaign was more uniform though Be deposition layers were visually recognized. The one of the possible explanations is enhanced desorption of T from Be deposition layers due to higher tile temperatures caused by higher energy input in the third campaign.