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Lahouij I.,LTDS ECL Ecully | Dassenoy F.,LTDS ECL Ecully | De Knoop L.,Nanofactory Instruments AB | Martin J.-M.,LTDS ECL Ecully | Vacher B.,LTDS ECL Ecully
Tribology Letters | Year: 2011

Inorganic fullerene-(IF)-like nanoparticles made of metal dichalcogenides (IF-MoS 2, IF-WS 2) have been known to be effective as anti-wear and friction modifier additives under boundary lubrication. The lubrication mechanism of these nanoparticles has been widely investigated in the past and even if the exfoliation and third body transfer of molecular sheets onto the asperities constitute the prevalent mechanism for the improved tribological behavior of IF nanoparticles, it has also been suggested that a rolling friction process could also play a role for well crystallized and spherical particles. In this study, in situ Transmission Electron Microscopy (TEM) observations of the behavior of single IF-MoS 2 nanoparticles were conducted using a sample holder that combines TEM and Atomic Force Microscopy (AFM) which simultaneously can apply normal and shear loads. It was shown that depending on the test conditions, either a rolling process or a sliding of the fullerenes could be possible. These in situ TEM observations are the first carried out with IF nanoparticles. © 2011 Springer Science+Business Media, LLC.

Park S.,University of Texas at Dallas | Kim M.J.,University of Texas at Dallas | Lourie O.,Nanofactory Instruments AB
Nano | Year: 2010

A novel approach in two-dimensional point probe electrical measurement in TEM is proposed to identify electrical properties at specific positions. This approach calls for a sharp W probe to be driven by piezo-motors in order to make contact with TEM samples and then proceeding IV measurements are taken and then scanned with constant bias. The doping type and pn junction interface can be identified by rectifying IV data obtained. By applying this method to a transistor device with a 200 nm gate length, we could qualitatively distinguish the doping area from the substrate. Mapping results with scanning probe revealed a presence of a dopant spreading region 60 nm wide at the junction interface. © 2010 World Scientific Publishing Company.

Agency: Cordis | Branch: FP7 | Program: CP-CSA-Infra | Phase: INFRA-2012-1.1.22. | Award Amount: 9.76M | Year: 2012

ESTEEM2 is an integrated infrastructure of electron microscopy facilities providing access for the academic and industrial research community in the physical sciences to some of the most powerful characterization techniques available at the nanoscale. Transnational access to ESTEEM2 centres is obtained through a transparent, simple peer review process based on merit and scientific priorities. Service to users is supported by a networking programme which addresses key issues such as specimen preparation, data interpretation through theory and simulation, and standardization of protocols and methodologies. A series of schools and workshops provide training in innovative methods in electron microscopy and a forum for discussing emerging (cutting-edge) techniques. Directed research programmes focus on the further development of electron diffraction, imaging and spectroscopy and the advancement of 3D methods and time resolved experiments. In all, ESTEEM2 establishes a strategic leadership in electron microscopy to guide future developments and promote electron microscopy to the wider research community at large.

Iannuzzi G.,Chalmers University of Technology | Nafari A.,Nanofactory Instruments AB | Boldizar A.,Chalmers University of Technology | Rigdahl M.,Chalmers University of Technology
Journal of Applied Polymer Science | Year: 2012

Surface defects associated with manufacturing processes can severely impair the appearance of polymeric products. These defects can be enhanced with ageing (time, UV-light, heat and weather conditions). In the present contribution, the interest is focused on the defects generated during injection molding of elastomer-modified polymers that are often used in the automotive sector to produce interior and exterior components. In particular, defects denoted as "flow marks" or "tiger stripes" were investigated. Two different grades of elastomer-modified polypropylene (PP)-containing mineral fillers were studied here before and after heat ageing for 9 weeks at a constant temperature of 95°C. Although injection moldings are one of the grades that did not exhibit any flow marks, moldings of other PP-grade showed such defects and they were enhanced after the ageing process. The properties and structure of the glossy and the dull bands (as well as the effect of the thermal ageing) have been assessed by several characteristics such as microhardness, nanohardness, crystallinity, and surface composition. An increase in surface hardness was noted after the ageing treatment as a consequence of increased crystallinity. Dull and glossy bands also exhibited different values of the nanohardness, glossy bands were harder, and the dull bands appeared to be less crystalline. The surface composition of glossy and dull regions was slightly different; the surface regions of the glossy areas contained higher amounts of filler particles. The effect of the ageing on the striped appearance is furthermore discussed in relation to possible depletion of the stabilizer system. © 2012 Wiley Periodicals, Inc.

Jansson A.,Chalmers University of Technology | Nafari A.,Chalmers University of Technology | Nafari A.,NanoFactory Instruments AB | Nafari A.,Epsilon AB | And 5 more authors.
Microscopy and Microanalysis | Year: 2013

Abstract Environmental scanning electron microscopy has been extensively used for studying the wetting properties of different materials. For some types of investigation, however, the traditional ways of conducting in situ dynamic wetting experiments do not offer sufficient control over the wetting process. Here, we present a novel method for controlled wetting of materials in the environmental scanning electron microscope (ESEM). It offers improved control of the point of interaction between the water and the specimen and renders it more accessible for imaging. It also enables the study of water transport through a material by direct imaging. The method is based on the use of a piezo-driven nanomanipulator to bring a specimen in contact with a water reservoir in the ESEM chamber. The water reservoir is established by local condensation on a Peltier-cooled surface. A fixture was designed to make the experimental setup compatible with the standard Peltier cooling stage of the microscope. The developed technique was successfully applied to individual cellulose fibers, and the absorption and transport of water by individual cellulose fibers were imaged. Copyright © Microscopy Society of America 2013.

Jansson A.,Chalmers University of Technology | Nafari A.,Nanofactory Instruments AB | Nafari A.,Chalmers University of Technology | Hedfalk K.,Gothenburg University | And 3 more authors.
Measurement Science and Technology | Year: 2014

We present a measurement system that combines an environmental scanning electron microscope (ESEM) and an atomic force microscope (AFM). This combination enables studies of static and dynamic mechanical properties of hydrated specimens, such as individual living cells. The integrated AFM sensor provides direct and continuous force measurement based on piezoresistive force transduction, allowing the recording of events in the millisecond range. The in situ ESEM-AFM setup was used to study Pichia pastoris wild-type yeast cells. For the first time, a quantified measure of the osmotic response of an individual yeast cell inside an ESEM is presented. With this technique, cell size changes due to humidity variations can be monitored with nanometre accuracy. In addition, mechanical properties were extracted from load-displacement curves. A Young's modulus of 13-15 MPa was obtained for the P. pastoris yeast cells. The developed method is highly interesting as a complementary tool for the screening of drugs directed towards cellular water transport activity and provides new possibilities of studying mechanosensitive regulation of aquaporins. © 2014 IOP Publishing Ltd.

Hatami S.,Chalmers University of Technology | Nafari A.,Nanofactory Instruments AB | Nyborg L.,Chalmers University of Technology | Jelvestam U.,Chalmers University of Technology
Wear | Year: 2010

Two types of powder metallurgical tool steels (i.e. with and without nitrogen) are investigated with respect to their galling related surface properties. Despite similar macrohardness values, Vancron 40 (nitrogen alloyed) exhibits superior wear behaviour as compared to Vanadis 10 (without nitrogen); demonstrating approximately 20 times longer life span when used as die material in powder compaction. The main failure mechanism is mild abrasive wear for Vancron 40 and early severe galling for Vanadis 10. One important difference causing the tribological discrepancy is supposed to be associated with the preferred formation of solid lubricant oxides of the Magnéli type on the Vancron 40 surface as compared to Vanadis 10. The VN precipitates in Vancron 40 have half the thermal conductivity compared to that of the VC precipitates existing in Vanadis 10. Hence, as a result of the local accumulation of frictional heat generated during powder compaction (or any other type of forming process), Magnéli phases of V2O5 and/or VO2 are more easily formed and maintained on the Vancron 40 surface. With regard to surface oxides, the tool steels were studied by means of X-ray photoelectron spectroscopy (XPS). The tool steel surfaces were examined by means in situ SEM/AFM and electron backscatter diffraction (EBSD) for local adhesion force measurements and understanding the orientation of the phases, respectively. In addition, pin-on-disc wear tests were performed on the tool steels and the worn surfaces were analysed using scanning election microscopy (SEM) combined with energy dispersive X-ray spectroscopy (EDS). © 2010 Elsevier B.V.

Nanofactory Instruments Ab | Date: 2010-04-15

The present invention relates to an optical arrangement and in particular to an optical arrangement for use in electron microscopy applications. This is used for sample characterization with simultaneous measurement with the electron microscopy of the sample and measurements with an optical setup and/or using a manipulator for probing of a light source or a scanning probe device.

Nafari A.,Nanofactory Instruments AB | Nafari A.,Chalmers University of Technology | Angenete J.,Nanofactory Instruments AB | Svensson K.,Karlstad University | And 2 more authors.
Journal of Micromechanics and Microengineering | Year: 2010

A capacitive force sensor for in situ transmission electron microscope (TEM)-nanoindentation with simultaneous force and current measurement has been developed. The sensor was fabricated using bulk micro machining methods such as deep reactive ion etch, thermal oxidation, metal deposition and anodic bonding. Two different geometries of the sensor were designed to allow in situ TEM electromechanical experiments in the most common TEM instruments. Electrical probing is enabled by an on-chip insulator, electrically separating the indenter tip and the capacitor used for force measurements. The sensor was designed for the force range of 0 to 4.5 mN. Finally, we demonstrate for the first time in situ TEM-nanoindentation with simultaneous force and current measurements. © 2010 IOP Publishing Ltd.

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