| 1. |
- Hsu, Tun-Wei, 1991-, et al.
(författare)
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Effects of substrate rotation during AlSi-HiPIMS/Ti-DCMS co-sputtering growth of TiAlSiN coatings on phase content, microstructure, and mechanical properties
- 2023
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Ingår i: Surface & Coatings Technology. - : Elsevier. - 0257-8972 .- 1879-3347. ; 453
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Tidskriftsartikel (refereegranskat)abstract
- A combined high-power impulse and dc magnetron co-sputtering (HiPIMS/DCMS) technique is used to deposit Ti0.6Al0.32Si0.08N films with 1-fold substrate table rotation. Layers are grown at two different substrate-target separations, two different rotational speeds, and with different values of substrate bias. The aim is to study the role of (1) overlap between ion and neutral fluxes generated from HiPIMS and DCMS sources, respectively, and (2) the subplantation range of low-mass ions. Results from X-ray diffractometry highlight the necessity of flux intermixing in the formation of the metastable B1-structured TiAlSiN solid solutions. All films grown at short target-to-substrate distance contain the hexagonal AlN phase, as there is essentially no overlap between HiPIMS and DCMS fluxes, thus the Al+ and Si+ subplantation is very limited. Under conditions of high flux intermixing corresponding to larger target-to-substrate distance, no w-AlN forms irrespective of rotational speed (1 or 3 rpm) and bias amplitude (120 or 480 V), indicating that the role of Al+/Si+ and Ti flux overlap is crucial for the phase formation during film growth by HiPIMS/DCMS with substrate rotation. This conclusion is further supported by the fact that the reduction of the bilayer thickness with increasing the target-to-substrate distance (hence increasing flux overlap) is larger for films grown with higher amplitude of the substrate bias, indicative of more efficient Al+/Si+ subplantation into the c-TiN phase. Single-phase films with the hardness close to that of layers grown with stationary substrate table can be achieved, however, at the expense of higher compressive stress.
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| 2. |
- Klemenso, Trine, et al.
(författare)
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High performance metal-supported solid oxide fuel cells with Gd-doped ceria barrier layers
- 2011
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Ingår i: Journal of Power Sources. - : Elsevier. - 0378-7753 .- 1873-2755. ; 196:22, s. 9459-9466
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Tidskriftsartikel (refereegranskat)abstract
- Metal-supported solid oxide fuel cells are believed to have commercial advantages compared to conventional anode (Ni-YSZ) supported cells, with the metal-supported cells having lower material costs, increased tolerance to mechanical and thermal stresses, and lower operational temperatures. The implementation of a metallic support has been challenged by the need to revise the cell fabrication route, as well as electrode microstructures and material choices, to compete with the energy output and stability of full ceramic cells. less thanbrgreater than less thanbrgreater thanThe metal-supported SOFC design developed at Riso DTU has been improved, and an electrochemical performance beyond the state-of-the-art anode-supported SOFC is demonstrated possible, by introducing a CGO barrier layer in combination with Sr-doped lanthanum cobalt oxide (LSC) cathode. Area specific resistances (ASR) down to 0.27 Omega cm(2), corresponding to a maximum power density of 1.14 W cm(-2) at 650 degrees C and 0.6 V. were obtained on cells with barrier layers fabricated by magnetron sputtering. The performance is dependent on the density of the barrier layer, indicating Sr(2+) diffusion is occurring at the intermediate SOFC temperatures. The optimized design further demonstrate improved durability with steady degradation rates of 0.9% kh(-1) in cell voltage for up to 3000 h galvanostatic testing at 650 degrees C and 0.25 A cm(-2).
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| 3. |
- Schönberg, Tommy, et al.
(författare)
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Surface embedded temperature sensor on tool part for real time injection moulding process monitoring
- 2013
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Ingår i: 2013 Transducers and Eurosensors XXVII. - 9781467359818 ; , s. 116-119
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Konferensbidrag (refereegranskat)abstract
- This paper reports successful temperature measurements from a real time production process using surface integrated sensors. K-type thermocouples were fabricated directly on the surface of a tool part using Direct Write Thermal Spray and the process temperature cycle from an injection moulding process was measured under real running conditions. The metal-polymer interface never got hotter than 100 °C as the >200 °C molten polymer is instantly solidified as it reaches the cold metal surface.
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| 4. |
- Sønderby, Steffen, et al.
(författare)
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Strontium diffusion in magnetron sputtered gadolinia-doped ceria thin film barrier coatings for solid oxide fuel cells
- 2013
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Ingår i: Advanced Energy Materials. - : John Wiley & Sons. - 1614-6840 .- 1614-6832. ; 3:7, s. 923-929
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Tidskriftsartikel (refereegranskat)abstract
- Strontium (Sr) diffusion in magnetron sputtered gadolinia-doped ceria (CGO) thin films is investigated. For this purpose, a model system consisting of a screen printed (La,Sr)(Co,Fe)O3−δ (LSCF) layer, and thin films of CGO and yttria-stabilized zirconia (YSZ) is prepared to simulate a solid oxide fuel cell. This setup allows observation of Sr diffusion by observing SrZrO3 formation using X-ray diffraction while annealing. Subsequent electron microscopy confirms the results. This approach presents a simple method for assessing the quality of CGO barriers without the need for a complete fuel cell test setup. CGO films with thicknesses ranging from 250 nm to 1.2 μm are tested at temperatures from 850 °C to 950 °C which yields an in-depth understanding of Sr diffusion through CGO thin films that may be of high scientific and technical interest for implementation of novel fuel cell materials. Sr is found to diffuse along column/grain boundaries in the CGO films but by modifying the film thickness and microstructure the breaking temperature of the barrier can be increased.
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