Browsing NTNU Open by Author "Vullum, Per Erik"
Now showing items 21-40 of 75
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Effect of Mn and cooling rates on α-, β- and δ-Al–Fe–Si intermetallic phase formation in a secondary Al–Si alloy
Becker, Hanka; Bergh, Tina; Vullum, Per Erik; Leineweber, Andreas; Li, Yanjun (Journal article; Peer reviewed, 2019)Secondary Al–Si alloys Al7.1Si(1.5-xMn)Fe(xMn)Mn with xMn = 0, 0.3, 0.375, 0.6, 0.75 at.% have been solidified with different cooling rates: 0.05 K/s, 1.4 K/s, 11.4 K/s and 200 K/s. In the ternary alloy with xMn = 0 at.%, ... -
Effect of polar (111)-oriented SrTiO3 on initial perovskite growth
Hallsteinsen, Ingrid; Nord, Magnus Kristofer; Bolstad, Torstein; Vullum, Per Erik; Boschker, Jos Emiel; Longo, Paulo; Takahashi, Ryota; Holmestad, Randi; Lippmaa, Mikk; Tybell, Per Thomas Martin (Journal article, 2016)In crystalline thin film growth a prerequisite is substrate surfaces with a stable and uniform structure and chemical composition. Various substrate treatments were used to obtain atomically smooth, step-and-terrace ... -
Effects of metal dusting relevant exposures of alloy 601 surfaces on carbon formation and oxide development
Guo, Xiaoyang; Vanhaecke, Estelle Marie M.; Vullum, Per Erik; Ma, Jianyu; Panditha Vidana, Daham Sanjaya Gunawardana; Walmsley, John; Chen, De; Venvik, Hilde Johnsen (Peer reviewed; Journal article, 2020)Ni and Fe are excellent catalysts for carbon formation, and industrial alloys are therefore susceptible to metal dusting corrosion; a costly issue in e.g. synthesis gas manufacture. The objective of this work is to better ... -
Electron Microscopy Characterization of Aluminium-Copper-Titanium-Steel Joint made using the Hybrid Metal Extrusion & Bonding Method
Turgun, Hursanay (Master thesis, 2020)Multimaterielle skjøter er nyttige i produksjon av lette strukturer med høy ytelse og funksjonalitet. Denne avhandlingen undersøker en skjøt sammensveiset ved bruk av den innovative Hybrid Metal Extrusion & Bonding (HYB) ... -
Electron microscopy of intermetallic phases in aluminium-steel joints
Bergh, Tina (Doctoral theses at NTNU;2021:168, Doctoral thesis, 2021)Joints that combine the light weight of aluminium (Al) alloys with the high strength of steels, can be beneficial in structural components. For instance, in automobiles, Al-steel joints can enable improvement of the ... -
Epitaxial (100), (110), and (111) BaTiO3 films on SrTiO3 substrates — A transmission electron microscopy study
Nylund, Inger-Emma; Ræder, Trygve Magnus; Vullum, Per Erik; Grande, Tor (Peer reviewed; Journal article, 2021)Chemical solution deposition (CSD) is a versatile method to fabricate oxide films. Here, the structure and local variations in the chemical composition of BaTiO3 (BTO) films prepared by CSD on (100), (110), and (111) SrTiO3 ... -
Epitaxial K0.5Na0.5NbO3 thin films by aqueous chemical solution deposition
Pham, Ky-Nam; Gaukås, Nikolai Helth; Morozov, Maxim; Tybell, Per Thomas Martin; Vullum, Per Erik; Grande, Tor; Einarsrud, Mari-Ann (Journal article; Peer reviewed, 2019)We report on an environmentally friendly and versatile aqueous chemical solution deposition route to epitaxial K0.5Na0.5NbO3 (KNN) thin films. The route is based on the spin coating of an aqueous solution of soluble ... -
Ferroelastic LaCoO₃-based polycrystalline ceramics : a transmission electron microscopy and X-ray diffraction study
Vullum, Per Erik (Doktoravhandlinger ved NTNU, 1503-8181; 2005:143, Doctoral thesis, 2005)In the present work rhombohedrally distorted LaCoO3-based materials have been studied using transmission electron microscopy, in situ synchrotron X-ray diffraction during uniaxial compression/decompression, and ex situ ... -
GaAs/AlGaAs Nanowire Array Solar Cell Grown on Si with Ultrahigh Power-per-Weight Ratio
Mukherjee, Anjan; Ren, Dingding; Vullum, Per Erik; Huh, Junghwan; Fimland, Bjørn-Ove; Weman, Helge (Peer reviewed; Journal article, 2021)Here we demonstrate a more effective use of III–V photoconversion material to achieve an ultrahigh power-per-weight ratio from a solar cell utilizing an axial p-i-n junction GaAs/AlGaAs nanowire (NW) array grown by molecular ... -
GaN/AlGaN nanocolumn ultraviolet light-emitting diode using double-Layer graphene as substrate and transparent electrode
Høiaas, Ida Marie; Liudi Mulyo, Andreas; Vullum, Per Erik; Kim, Dong Chul; Ahtapodov, Lyubomir; Fimland, Bjørn-Ove; Kishino, Katsumi; Weman, Helge (Journal article, 2019)The many outstanding properties of graphene have impressed and intrigued scientists for the last few decades. Its transparency to light of all wavelengths combined with a low sheet resistance makes it a promising electrode ... -
Graphene-Based Transparent Conducting Substrates for GaN/AlGaN Nanocolumn Flip-Chip Ultraviolet Light-Emitting Diodes
Liudi Mulyo, Andreas; Mukherjee, Anjan; Høiaas, Ida Marie; Ahtapodov, Lyubomir; Nilsen, Tron Arne; Toftevaag, Håvard Hem; Vullum, Per Erik; Kishino, Katsumi; Weman, Helge; Fimland, Bjørn-Ove (Journal article; Peer reviewed, 2021)Flip-chip ultraviolet light-emitting diodes based on self-assembled GaN/AlGaN nanocolumns have been fabricated, exploiting single-layer graphene not only as a growth substrate but also as a transparent conducting electrode. ... -
Heat Treatment of Mg-Containing Aluminum Alloys 5182 and 6016 in an Oxidizing Atmosphere with 4% CO2
Solem, Cathrine Kyung Won; Vullum, Per Erik; Tranell, Gabriella; Aune, Ragnhild Elizabeth (Peer reviewed; Journal article, 2022)Oxidation of liquid aluminum (Al) during processing is a widely known problem, and magnesium (Mg), as a common alloying element, increases the oxidation rate of the alloy. It has been established that small additions of ... -
High capacity Mg batteries based on surface-controlled electrochemical reactions
Wang, Lu; Vullum, Per Erik; Asheim, Karina; Wang, Xuehang; Svensson, Ann Mari; Vullum-Bruer, Fride (Journal article; Peer reviewed, 2018)Mg batteries are one of several new battery technologies expected to partially substitute lithium-based batteries in the future due to the lower cost and higher safety. However, the development of Mg batteries has been ... -
High interfacial charge storage capability of carbonaceous cathodes for Mg batteries
Wang, Lu; Jiang, Bo; Vullum, Per Erik; Svensson, Ann Mari; Erbe, Andreas; Selbach, Sverre Magnus; Xu, Huailiang; Vullum-Bruer, Fride (Journal article; Peer reviewed, 2018)A rechargeable Mg battery where the capacity mainly originates from reversible reactions occurring at the electrode/electrolyte interface efficiently avoids the challenge of sluggish Mg intercalation encountered in ... -
Improved cyclability of Nickel-rich layered oxides
Wagner, Nils Peter; Tolchard, Julian R; Tron, Artur; Pollen, Harald Norrud; Gaertner, Heiko; Vullum, Per Erik (Peer reviewed; Journal article, 2020)This study compares the physico- and electro- chemical properties of LiNi0.8Mn0.10Co0.1O2 (NMC811) and LiNi0.83Mn0.06Co0.09Al0.1O2 (NMCA) prepared by an oxalic acid co-precipitation. Deposition of a SiO2 surface coating ... -
Improved electrochemical performance and solid electrolyte interphase properties of electrolytes based on lithium bis(fluorosulfonyl)imide for high content silicon anodes
Asheim, Karina; Vullum, Per Erik; Wagner, Nils Peter; Andersen, Hanne Flåten; Mæhlen, Jan Petter; Svensson, Ann Mari (Journal article; Peer reviewed, 2022)Electrodes containing 60 wt% micron-sized silicon were investigated with electrolytes containing carbonate solvents and either LiPF6 or lithium bis(fluorosulfonyl)imide (LiFSI) salt. The electrodes showed improved performance, ... -
The influence of AlN buffer layer on the growth of self-assembled GaN nanocolumns on graphene
Liudi Mulyo, Andreas; Rajpalke, Mohana; Vullum, Per Erik; Weman, Helge; Kishino, Katsumi; Fimland, Bjørn-Ove (Peer reviewed; Journal article, 2020)GaN nanocolumns were synthesized on single-layer graphene via radio-frequency plasma-assisted molecular beam epitaxy, using a thin migration-enhanced epitaxy (MEE) AlN buffer layer as nucleation sites. Due to the weak ... -
Inhibition of metal dusting corrosion on Fe-based alloy by combined near surface severe plastic deformation (NS-SPD) and thermochemical treatment
Guo, Xiaoyang; Vullum, Per Erik; Venvik, Hilde Johnsen (Peer reviewed; Journal article, 2021)Combined NS-SPD and thermochemical treatment has been used to improve the metal dusting corrosion resistance of Incoloy 800. After testing under infinite carbon activity for 20−100 h, carbon was not found in the NS-SPD ... -
Inside the electrode: Looking at cycling products in Li/O2 batteries
Augustin, Matthias; Vullum, Per Erik; Vullum-Bruer, Fride; Svensson, Ann Mari (Journal article; Peer reviewed, 2019)This work investigates the impact of electrochemical reactions and products on discharge capacity and cycling stability with electrolytes based on two common solvents – tetraethylene glycol dimethyl ether (TEGDME) and ... -
Interface Microstructure and Tensile Properties of a Third Generation Aluminium-Steel Butt Weld Produced Using the Hybrid Metal Extrusion & Bonding (HYB) Process
Sandnes, Lise; Bergh, Tina; Grong, Øystein; Holmestad, Randi; Vullum, Per Erik; Berto, Filippo (Peer reviewed; Journal article, 2021)The Hybrid Metal Extrusion & Bonding (HYB) process is a patented solid state joining method for metals which utilizes filler material additions to consolidate the weld. In the present investigation the interface microstructure ...