1,721,366 research outputs found
Grabbing pebbles out of my shoes: Thoughts of a grumpy old researcher on publishing research
No full textSteam electrolysis by proton-conducting solid oxide electrolysis cells (SOECs) with chemically stable BaZrO3-based electrolytes
No full textBaZrO3-based material was applied as the electrolyte for proton-conducting solid oxide fuel cells (SOECs). Compared with the instability of BaCeO3-based proton-conductors, BaZrO3-based material could be a more promising candidate for proton-conducting SOECs due to its excellent chemical stability under H2O conditions, but few reports on this aspect has been made due to the processing difficulty for BaZrO3. Our recent pioneering work has demonstrated the feasibility of using BaZrO3-based electrolyte for SOECs and the fabricated cell achieves relatively high cell performance, which is comparable or even higher than that for BaCeO3-based SOECs and offers better chemical stability. Cell performance can be further improved by tailoring the electrolyte and electrode
A chemically stable electrolyte with a novel sandwiched structure for proton-conducting solid oxide fuel cells (SOFCs)
No full textA chemically stable electrolyte structure was developed for proton-conducting SOFCs by using two layers of stable BaZr0.7Pr 0.1Y0.2O3 -δ to sandwich a highly-conductive but unstable BaCe0.8Y0.2O 3 -δ electrolyte layer. The sandwiched electrolyte structure showed good chemical stability in both CO2 and H2O atmosphere, indicating that the BZPY layers effectively protect the inner BCY electrolyte, while the BCY electrolyte alone decomposed completely under the same conditions. Fuel cell prototypes fabricated with the sandwiched electrolyte achieved a relatively high performance of 185 mW cm- 2 at 700 C, with a high electrolyte film conductivity of 4 × 10- 3 S cm- 1 at 600 C. © 2013 Elsevier B.V
Editorial: Chemistry, a sustainable bridge from waste to materials for energy and environment
Full text linkSolid oxide fuel cells with proton-conducting La0.99Ca0.01NbO4 electrolyte
No full textSeveral proton conductive ceramic oxides are evaluated for potential application in ceramic-NiO composite anodes for proton-conducting La0.99Ca0.01NbO4 (LNO) electrolyte-based fuel cells. Chemical compatibility tests show that most of the existing proton-conducting oxides are unfavorable for application in LNO electrolyte-based fuel cells because of undesirable reactions at high temperatures. Further considering the chemical compatibility with NiO and the ability to promote the densification of the deposited LNO electrolyte, LNO-NiO composite anode proves to be the only suitable anode candidate. With humidified hydrogen (∼3%H2O) as the fuel and static air as the oxidant, fuel cells based on LNO electrolyte film deposited on LNO-NiO anodes show a peak power density of 24 mW cm−2 at 750 °C, this value being one of the largest ever reported for LNO-based cells. Further investigation reveals that the polarization resistance of the cell is the major contribution to the total cell resistance, limiting the overall cell performance
Procedimento per la produzione di un substrato in metallo duro rivestito con pellicola aderente di diamante
Full text linkProcedimento per la realizzazione di un rivestimento protettivo antiusura di diamante su manufatti in metallo duro mediante deposizione chimica da fase vapore (CVD), in cui la fase metallica che agisce da legante nel materiale in metallo duro, usualmente responsabile della scarsa adesione della pellicola di diamante, viene eliminata dalla superficie del substrato durante le prime fasi dello stesso processo di deposizione.
Nel corso del processo, la temperatura interna del substrato viene dapprima mantenuta a 600-800 °C per consentire la nucleazione del diamante e la segregazione superficiale di una fase contenente la fase metallica legante, poi innalzata a 900-1100 °C per ottenere la rimozione della fase metallica legante dalla superficie del substrato e quindi mantenuta a 600-900 °C per un tempo sufficiente ad ottenere lo spessore desiderato di pellicola di diamante
Diamond as a wear-resistant coating for cutting tools, part 2
No full textSince the discovery of diamond film synthesis by chemical vapour deposition (CVD), many technologically important applications have been developed. In the machining industry, Co-cemented tungsten carbide (WC-Co) tool inserts can benefit from CVD diamond technology insofar as their wear life is concerned. However, premature failure of diamond-coated WC-Co tools caused by thermal and mechanical stresses still remains a challenging difficulty. In this paper, the authors discuss the state-of-the-art of CVD diamond films adhesion, since the most important failure mechanisms of diamond-coated hard metal tools are usually related to film delamination during machining. The main issues related to the development of CVD diamond-coated wear re sistant parts are addressed. The literature analysis shows that substrate surface pretreatments play an important role in determining sufficiently large interface toughness values. Therefore, a survey of advancements in techniques to enhance adhesion of CVD diamond coatings is presented. In addition, the combined effect of substrate pretreatment and microstructure on the cutting performance of CVD diamond-coated WC-Co inserts is discussed on the basis of metal matrix composites (MMCs) machining results
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