| 1. |
- Stefanov, P, et al.
(författare)
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Electrochemical deposition of thin zirconia films on stainless steel 316 L
- 2000
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Ingår i: Materials Chemistry and Physics. - 0254-0584 .- 1879-3312. ; 65:2, s. 222-225
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Tidskriftsartikel (refereegranskat)abstract
- Zirconia films (ZrO2) have been deposited electrochemically on stainless steel SS 316 L in a non-aqueous electrolyte based on absolute ethyl alcohol and ZrCl4. Scanning electron microscopy (SEM) studies have shown that the film consists of crystallites with a spheroidal shape, forming agglomerates with a very large surface area. Their sizes vary within the range of 0.1–0.5 μm. The layer composition is very close to the stoichiometric ZrO2, as has been determined by X-ray photoelectron spectroscopy (XPS).
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| 2. |
- Öhman, Lars-Olof, et al.
(författare)
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Catalyst preparation through ion-exchange of zeolite Cu-, Ni-, Pd-, CuNi- and CuPd-ZSM-5
- 2002
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Ingår i: Materials Chemistry and Physics. - 0254-0584 .- 1879-3312. ; 73:2-3, s. 263-267
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Tidskriftsartikel (refereegranskat)abstract
- Ion-exchanged zeolite ZSM-5 is the best known catalyst for direct NOx decomposition and a viable candidate for NOx reduction with methane. The preparation is crucial for the efficiency of the conversion and this paper describes the ion-exchange, with Cu2+, Ni2+ or Pd2+, and the dual exchange, with Cu2+/Ni2+ or Cu2+/Pd2+, under appropriate pH and ion concentrations for maximum dispersion.
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| 3. |
- Öhman, Lars-Olof, et al.
(författare)
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Materials aspects of titanium-doped aluminas: 14%Ti/-Al2O3/Cu and sulfided Al2O3-TiO2/NiMo
- 2002
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Ingår i: Materials Chemistry and Physics. ; 73:2-3, s. 242-251
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Tidskriftsartikel (refereegranskat)abstract
- Materials aspects of titanium-doped alumina catalysts are discussed in light of a partly new synthesis route, ion exchange reactions and sulfidation. Starting with a solution of the isopropoxides of aluminum and titanium, we aimed at an Al:Ti ratio of 6:1, which corresponds to the maximum acidity of the final product. Transmission electron micrographs showed that the synthesis gave a product of nearly monodisperse, rectangular particles and X-ray diffractograms revealed an amorphous to nano-crystalline structure reminiscent of -Al2O3. The Brunauer-Emmet-Teller area was 340m2g-1 and the H+ titration found 3acidic sitesnm-2. These numbers indicate that the titanium modification may fourfold increase the ion exchange capacity of a regular alumina. The importance of titanium modification for catalysis is discussed in connection with selective catalytic reduction with hydrocarbon reactions over Cu/14%Ti-Al2O3 and hydrogenation of 1-Me-naphthalene over sulfided NiMo/Al2O3-TiO2. The Ti4+ ions in the alumina lattice are almost irreducible, but infrared spectra suggested that these ions act as dispersion agents not only for adsorbed Cu2+ ions, but also for a supported phase of sulfided NiMo. Finally, we show that a simple weight control can be used to monitor the sulfidation and to indicate if the synthesis has produced a separate, reducible titania phase.
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| 4. |
- Al Khabouri, Saja, et al.
(författare)
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Structure, composition and enhanced magnetic properties of novel ternary multicore-shell Ni-Co-Cr nanoclusters prepared by one-step inert gas condensation method
- 2021
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Ingår i: Materials Chemistry and Physics. - : Elsevier BV. - 0254-0584 .- 1879-3312. ; 271
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Tidskriftsartikel (refereegranskat)abstract
- We have synthesized ternary Ni-Co-Cr nanoclusters using one step method by simultaneous sputtering of metallic targets through inert gas condensation (IGC) deposition process. The difference in surface energy between the component atoms creates a preferential surface phase leading to the formation of multi core/shell structures. Surface structure and composition analysis reveal metallic and oxide phases characterized by extraordinary 1.43 mu m periodicity strong magnetic stripe domains with weak magnetic force microscopy signal attenuation up to a lift height value of 2.5 mu m. In addition, the ternary nanoclusters exhibit strong ferromagnetic behavior below the blocking temperature of 139 K with coercivity of 700 Oe at 4 K. The enhanced magnetic properties are attributed to Volmer-Weber growth mechanism and pave a facile way for preparing ternary core/ shell magnetic structures needed for applications which require strong magnetic anisotropy along their growth direction.
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| 5. |
- Alinejadian, Navid, et al.
(författare)
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Electro-deposited nano-Ni/reduced graphene oxide composite film of corrugated surface for high voltammetric sensitivity
- 2023
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Ingår i: Materials Chemistry and Physics. - : Elsevier BV. - 0254-0584 .- 1879-3312. ; 297, s. 127288-
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Tidskriftsartikel (refereegranskat)abstract
- Reduced graphene oxide (rGO) is an ideal candidate in nanostructured metallic materials to enhance their electrochemical performance. However, few studies exist on the effects of rGO on the crystallographic, physical, and topological properties of co-electrodeposited Ni/rGO nanocomposites. In this study, the morphology and normalized electro-active specific surface (NESS) of a Ni/rGO nanocomposite were correlated with its crystal-lographic properties by varying the applied co-electrodeposition current density (0.01-0.1 A cm(-2)) and rGO concentration (0.5-2 mg mL(-1)). Tuning was done to achieve the best physical and electrochemical properties of the nanocomposite at alkaline (NaOH) conditions in terms of the highest NESS (12.3 x 10(-4)) and electro-active sensitivity (17.3 mu A mM(-1) cm(-2)) possible. The findings of the study show a possible approach to enhance the performance of electro-active components such as electrochemical devices, sensors, and actuators.
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| 6. |
- Aminlashgari, Nina, et al.
(författare)
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Degradation product profiles of melt spun in situ cross-linked poly(epsilon-caprolactone) fibers
- 2015
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Ingår i: Materials Chemistry and Physics. - : Elsevier BV. - 0254-0584 .- 1879-3312. ; 156, s. 82-88
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Tidskriftsartikel (refereegranskat)abstract
- In situ cross-linking of poly(epsilon-caprolactone) (PCL) fiber with bis-(epsilon-caprolactone-4-yl) (BCY) was shown to be a feasible approach to compensate for reduction in molar mass of PCL during melt-spinning. The effect of in situ cross-linking on the degradation profile of melt spun PCL fibers with different amounts of BCY was evaluated using electrospray ionization-mass spectrometry. Degradation of the cross-linked fibers was carried out in aqueous medium at 37 degrees C and 60 degrees C for different periods of time. The degradation profiles were then compared with uncross-linked fiber and 3D porous cross-linked film of PCL Interesting differences in the degradation product profiles with linear, cyclic or BCY-related low molar mass compounds were observed, clearly demonstrating the effect of cross-linking and processing on the degradation process and formation of water-soluble products. In addition the degradation product profiles demonstrated that in situ cross-linking is a feasible technique for counteracting degradation reactions during melt-spinning.
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| 7. |
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| 8. |
- Berzins, A., et al.
(författare)
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Characterization of microscopic ferromagnetic defects in thin films using magnetic microscope based on Nitrogen-Vacancy centres
- 2021
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Ingår i: Materials Chemistry and Physics. - : ELSEVIER SCIENCE SA. - 0254-0584 .- 1879-3312. ; 267
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Tidskriftsartikel (refereegranskat)abstract
- In this work we present results acquired by applying magnetic field imaging technique based on NitrogenVacancy centres in diamond crystal for characterization of magnetic thin films defects. We used the constructed wide-field magnetic microscope for measurements of two kinds of magnetic defects in thin films. One family of defects under study was a result of non-optimal thin film growth conditions. The magnetic field maps of several regions of the thin films created under very similar conditions to previously published research revealed microscopic impurity islands of ferromagnetic defects, that potentially could disturb the magnetic properties of the surface. The second part of the measurements was dedicated to defects created post deposition - mechanical defects introduced in ferromagnetic thin films. In both cases, the measurements identify the magnetic field amplitude and distribution of the magnetic defects. In addition, the magnetic field maps were correlated with the corresponding optical images. As this method has great potential for quality control of different stages of magnetic thin film manufacturing process and it can rival other widely used measurement techniques, we also propose solutions for the optimization of the device in the perspective of high throughput.
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| 9. |
- Berzins, Andris, et al.
(författare)
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Surface magnetic structure investigation of a nanolaminated Mn2GaC thin film using a magnetic field microscope based on Nitrogen-Vacancy centers
- 2021
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Ingår i: Materials Chemistry and Physics. - : Elsevier. - 0254-0584 .- 1879-3312. ; 272
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a magnetic field imaging method based on color centers in diamond crystal applied to a thin film of a nanolaminated Mn2GaC MAX phase. Magnetic properties of the surface related structures have been described around the first order transition at 214 K by performing measurements in the temperature range between 200 K and 235 K with the surface features fading out by increasing temperature above the transition temperature. The results presented here demonstrate how Nitrogen-Vacancy center based magnetic microscopy can supplement the traditionally used set of experimental techniques, giving additional information of microscopic scale magnetic field features, and allowing to investigate the temperature dependent magnetic behavior. The additional information acquired in this way is relevant to applications where surface magnetic properties are of the essence.
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| 10. |
- Bhattacharjee, T., et al.
(författare)
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Effect of low temperature on tensile properties of AlCoCrFeNi2.1 eutectic high entropy alloy
- 2018
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Ingår i: Materials Chemistry and Physics. - : Elsevier BV. - 0254-0584. ; 210, s. 207-212
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Tidskriftsartikel (refereegranskat)abstract
- The effect of low temperature on tensile properties of a AlCoCrFeNi 2.1 eutectic high entropy alloy (EHEA) was investigated in the present work. Transmission electron microscopy (TEM) showed that the initial as-cast microstructure consisted of B2 (ordered body centered cubic structure) and L1 2 (ordered face centered cubic structure) phases. Upon tensile testing at temperatures ranging from room temperature (RT) to −196 °C (77 K), the L1 2 phase became disordered, changing to a simple FCC (face centered cubic) crystal structure whereas the B2 phase maintained an ordered structure. An increase over 300 MPa was observed in the ultimate tensile strength (σ UTS ) of the −196 °C tensile tested sample compared to the room temperature tensile tested sample, while keeping almost similar amount of total elongation. TEM results indicated an increase in the dislocation activity in the FCC phase as well as B2 phase in the −196 °C tensile tested sample compared to the sample deformed at room temperature.
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