| 1. |
- Srepusharawoot, Pornjuk, 1979-, et al.
(författare)
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Hydrogen Binding in Alkali-decorated Iso-reticular Metal Organic Framework-16 based on Zn, Mg, and Ca
- 2011
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 36:1, s. 555-562
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen adsorption energies were investigated in three different types of iso-reticular Metal Organic Framework-16, Zn-/Mg-/Ca-MOF16, decorated with either Li, Na, or K. Concerning the binding strengths of the alkali metals, the density functional theory calculations reveal that Li is bound strongest to the host framework, followed by K and Na. Decoration with Li also results in the highest hydrogen adsorption energies among the studied alkali metals. Furthermore, Zn-MOF16 exhibits the highest hydrogen adsorption energies near the metal oxide cluster, while hydrogen binding strengths at organic linker sites do not differ substantially between Zn-/Mg-/Ca-MOF16. Based on these results, we conclude that for Metal Organic Framework-16, Li-decorated Zn-MOF16 appears to be the optimal choice for hydrogen storage among the nine combinations.
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| 2. |
- Borgh, Ida, et al.
(författare)
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Investigation of phase separation in the (TI, ZR)C system
- 2012
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Ingår i: Advances in Powder Metallurgy and Particulate Materials - 2012, Proceedings of the 2012 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2012. - 9780985339722 ; , s. 81-810
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Konferensbidrag (refereegranskat)abstract
- The hardness of cemented carbide (WC-Co) cutting tools can be improved by the addition of TiC or ZrC to the matrix. It is possible that an even better hardness can be obtained by utilizing phase separation of a mixed (Ti, Zr)C where the mixed (Ti, Zr)C phase is stable at high temperature, but decomposes to TiC and ZrC at lower temperatures. In the present work, the decomposition is experimentally and theoretically investigated. The mixed carbide is first formed by synthesis from oxide powders at 2200°C and aging treatments are conducted at 1380 and 1450°C. X-ray diffraction analysis show that the synthesized mixed (Ti, Zr)C will decompose to TiC and ZrC. The experimental work is supplemented by thermodynamic and first-principles calculations.
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| 3. |
- Århammar, C., et al.
(författare)
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Probing temperature-induced ordering in supersaturated Ti-1 (-) xAlxN coatings by electronic structure
- 2014
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 242, s. 207-213
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Tidskriftsartikel (refereegranskat)abstract
- The ordering of supersaturated cubic titanium aluminum nitride (c-Ti0.35Al0.65N) coatings is probed from room temperature up to and above the point of spinodal decomposition, using Near Edge X-ray Absorption Fine-structure (NEXAFS) and first principles calculations. The measured and calculated nitrogen (N) K spectra suggest that unoccupied N p states hybridize with Ti d states. When temperature is raised the N p-Ti d overlap decreases, whereas hybridization between N p and Al p tends to increase. The observed spectral changes with temperature together with calculations of defect heat of formation suggest a depletion of N in the surroundings of Ti in c-Ai(1) (-) xAlxN and/or in the formed c-TiN.
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| 4. |
- Ekström, Madeleine, 1984-, et al.
(författare)
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Evaluation of internal thermal barrier coatings for exhaust manifolds
- 2015
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Ingår i: Surface & Coatings Technology. - : Elsevier. - 0257-8972 .- 1879-3347. ; 272, s. 198-212
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Tidskriftsartikel (refereegranskat)abstract
- Seven different thermal barrier coatings (TBC) intended for coating the inside of an exhaust manifold to reduce its material temperature were studied. They comprised five plasma-sprayed (mullite, forsterite, La2Zr2O7, 8YSZ, and nanostructured 8YSZ) and two sol-gel composite (one sprayed and one dipped) coatings, which were examined for their thermal insulation properties and oxidation and spallation resistance. Thermal cyclic tests in air and in exhaust gas in a diesel test engine showed that thermal expansion mismatch between substrate and TBC was most crucial for TBC lifetime. Moreover, thermal modeling indicated that it is possible to reduce the material temperature by 50 °C, which is important for improving the fatigue life of exhaust manifolds. This reduction can be obtained with a 0.2 mm thick TBC with thermal conductivity close to 0.1 W/m K, or a 3–6 mm thick TBC with thermal conductivity 1.5–3 W/m K.
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