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Aakkula J.,Aalto University | Jokinen J.,Aalto University | Saarela O.,Aalto University | Tervakangas S.,DIARC Technology Inc.
International Journal of Adhesion and Adhesives | Year: 2016

The stability and durability of DIARC vacuum plasma surface treatment was tested for structural bonding with elastic-plastic steel wedge test specimens. In the treatment nanostructured DIARC Bindo coating is deposited on the substrates in a vacuum chamber. The DIARC-treated surface is ready for bonding and does not require any additional treatments, chemicals or primers containing hazardous CrVI chromium. The tests were performed at hot and wet exposure. Virtual Crack Closure Technique (VCCT) was successfully used in the design of test specimens and in the analyses of the results. Five-year-old DIARC coating performed equally with the freshly-bonded DIARC specimens. The results were also comparable with the best results achieved with existing grit-blast silane and grit-blast Sol-Gel primer methods with aluminium and titanium. © 2016 Elsevier Ltd. All rights reserved.

Agency: Cordis | Branch: FP7 | Program: CP-FP | Phase: NMP-2009-2.1-1 | Award Amount: 3.82M | Year: 2010

The RODIN-project, which seamlessly integrates experimental, industrial and theoretical work, is organized around the concept of suspended single-and few-layer graphene nanostructures and annealed diamond-like carbon films. These structures are ideal for accessing and engineering the intrinsic material properties of graphene. In particular we will focus on engineering and measuring the mechanical and electromechanical properties. This will be done through sculpting of the suspended structures to desired shapes as well as using thermal post-processing methods. Initially, the graphene will be obtained using standard prototype techniques such as exfoliation and plasma assisted chemical vapor deposition. The main goal of the project, one that requires going beyond the current state of the art in multiple areas and has rapid and substantial industrial impact, is the fabrication and demonstration of a tunable graphene resonator with electronic readout. The performance of a mechanical resonator depends sensitively on materials quality, which makes it an ideal test application for a materials-oriented project.

Koskinen J.,University of Helsinki | Tapper U.,VTT Technical Research Center of Finland | Andersson P.,VTT Technical Research Center of Finland | Varjus S.,VTT Technical Research Center of Finland | And 3 more authors.
Surface and Coatings Technology | Year: 2010

It has been demonstrated that tetrahedral amorphous carbon (ta-C) films provide excellent wear and friction properties in dry sliding. Recently the applications of ta-C coatings in lubricated conditions have become more important. The use of carbon coatings aims at reducing the wear and coefficient of friction under minimum lubrication and without hazardous lubricant additives. For optimum tribological performance, a modification of the ta-C coated surfaces is required. The present paper describes an innovative method of coated surface texturing, by which nanometer and micrometer size pores are processed by various methods. Particle masking was used for processing micrometer size pores and for controlling the coating growth conditions in order to produce nanometer size pores in the ta-C surface. The masking by particles yielded a pore geometry which varied from complex shaped channels to small individual pores. The texturing was performed by distributing metallic powder particles on the surface or by direct chemical deposition of metal particles on the substrate in prior to pulsed vacuum arc deposition. The tribological characterization was carried out by applying reciprocating friction tests with controlled lubricant replenishment, in order to simulate metal forming processes. The friction reducing effect, which was observed in the tribological tests, indicated a microlubrication effect of the textured coating surfaces. © 2010 Elsevier B.V.

Tomi M.,Aalto University | Isacsson A.,Chalmers University of Technology | Oksanen M.,Aalto University | Lyashenko D.,Aalto University | And 4 more authors.
Nanoscale | Year: 2015

We have developed capacitively-transduced nanomechanical resonators using sp2-rich diamond-like carbon (DLC) thin films as conducting membranes. The electrically conducting DLC films were grown by physical vapor deposition at a temperature of 500 °C. Characterizing the resonant response, we find a larger than expected frequency tuning that we attribute to the membrane being buckled upwards, away from the bottom electrode. The possibility of using buckled resonators to increase frequency tuning can be of advantage in rf applications such as tunable GHz filters and voltage-controlled oscillators. © 2015 The Royal Society of Chemistry.

Agency: Cordis | Branch: FP7 | Program: CP-FP | Phase: NMP-2007-2.1-2 | Award Amount: 4.74M | Year: 2008

The aim of this project is to develop high density defect-free ultra-thin sealing coatings with excellent barrier properties and improved corrosion resistance. Their successful functioning will be provided by the synergy of the coating perfect morphology and its complex structural design, which can be tailored at the nanoscale. The study will be focused on development of novel nanostructured coating systems, such as nanoscale multilayers, mixed and composite coatings. These impermeable sealing layers must be able to block the ion exchange between the substrate material and an aggressive environment, thus offering an efficient protection against corrosion over a long term. The coatings will be deposited by four alternative vapour deposition techniques, Filtered Cathodic Arc Deposition (FCAD), High Power Impulse Magnetron Sputtering (HIPIMS), Atomic Layer Deposition (ALD) and Plasma Enhanced Atomic layer Deposition (PEALD)). These techniques possess a unique advantage offering the deposition of highly conformal and uniform films of high density, free of defects. The technological objective of the project is to demonstrate the feasibility of corrosion protection by FCAD, HIPIMS and ALD techniques on an industrial scale. To fulfil this objective, a complete industrial process for the multi-stage surface treatment, including cleaning, pre-treatment, coating deposition, must be defined. All techniques will be evaluated in terms of technical effectiveness, production costs, environmental impact and safety, and the most suitable technique(s) will be selected for further development on a large scale for the applications in some targeted industrial sectors. The applications, tested within this project, concern high precision mechanical parts (bearings), aerospace components (break systems) and gas handling components. The coating application in the decorative and biomedical domains will be assessed.

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