ICMCTF 2012! - CD-Lab Application Oriented Coating Development

fluidized bed of tin, zinc and aluminium powders at ambient temperature.
Coating process was achieved by first depositing a solventborne organic
bond layer on the substrate surface. After drying, the pre-coated substrates
were dipped in the fluidized metal powders, which were retained on the
surface of the adhesive bond layer. Following this, the powder coated
substrates were baked in a convection oven to melt the metal powders, until
a continuous film was formed. The interaction between metal powders and
the substrates pre-coated with the organic bong layer was studied,
identifying the effect of the main process parameters, such as dipping time,
fluidization velocity and metal powder mesh size. The role of the baking
temperature and time was investigated, as well. The thickness and surface
morphology of the resulting coatings was evaluated as a function of the
process parameters by Field Emission Gun – Scanning Electron Microscopy
(FEG-SEM) and contact gauge prof ilometry. Their hardness and scratch
resistance were evaluated by instrumented scratch and indentation testing.
Wear performance of the coated substrates were tested by dry sliding linear
reciprocating with stainless steel counterpart. CD – FBC allowed the
deposition of high performance coatings, whose morphological, mechanical
and tribological response could be directly related to the coating thickness
and baking conditions.
Key words: Fluidized Bed; Metal Powders; Cold Dipping; Morphology;
Hardness; Scratch; Wear.
Graphene and 2D Nanostructures
Room: Sunset - Session TS4-1
Graphene and 2D Nanostructures
Moderator: M. Chhowalla, Rutgers University, US, C.
Teichert, Montanuniversität Leoben, Austria
8:00am TS4-1-1 Intercalation compounds and cluster superlattices:
graphene based 2D composites, T. Michely (michely@ph2.uni-koeln.de),
University of Cologne, Germany INVITED
Carefully optimizing the growth of graphene on Ir(111) by scanning
tunneling microscopy and low energy electron microscopy yields a virtually
defect free, weakly bound epitaxial monolayer of macroscopic extension.
Graphene on Ir(111) can be used as a laboratory to construct new types of
graphene based compound materials. Specifically, patterned adsorption of
atoms and molecules takes place resulting in cluster superlattices with
exciting magnetic and catalytic properties. Intercalation underneath the
graphene allows one to manipulate the properties of graphene itself, e.g. its
ability to adsorb atoms and molecules as well as its magnetism.
8:40am TS4-1-3 Growth Kinetics of Monolayer and Multilayer
Graphene on Pd(111), H.S. Mok, Y. Murata, University of California, Los
Angeles, US, S. Nie, N. Bartelt, K. McCarty, Sandia National Laboratories,
US, S. Kodambaka (kodambaka@ucla.edu), University of California, Los
Angeles, US
Graphene, a two dimensional crystalline sheet of carbon, has attracted
significant attention due to its electronic properties, including a tunable
band gap and high electron mobility for use in semiconducting devices and
sufficiently high transparency and low sheet resistance for use as a
transparent conductor. For any of these applications, it is desirable to obtain
single-crystalline graphene layers with uniform thickness. This is an
extremely challenging task that requires a fundamental understanding of the
mechanisms controlling the nucleation and growth of graphene. Here, using
in situ low-energy microscopy (LEEM), we investigated the growth of
graphene via surface segregation of carbon dissolved in the bulk of the
substrate. In this process, surface concentration of carbon depends on the
substrate temperature T: at T > 920 o C the Pd surface is free of carbon; upon
cooling to 880 o C, we observer monolayer graphene formation on the
surface; and, at T = 710 o C, we obtain multi-layer graphene. In order the
follow the kinetics of graphene growth, we acquired LEEM images as a
function of incident electron energy while cooling the sample from 920 o C
to 880 o C. From the LEEM images, electron reflectivity (electron energy
dependent variations in image intensities) values, a measure of local surface
work function, are extracted. This data is used to follow the changes in
surface carbon adatom concentration during nucleation and growth of
graphene. For monolayer growth, we find that the electron reflectivity
decreases non-linearly with annealing time. This behavior is qualitatively
similar to that observed during the growth of graphene on Ru(0001) [1],
where the graphene layers grow from carbon adatoms present on the
surface. In case of multilayer graphene growth induced by cooling the
sample to lower temperatures (< 710 o C), we observed spontaneous
formation of graphene mounds consisting of multiple layers. Low-energy
electron diffraction patterns acquired from the layers reveal that both in-
plane and out-of-plane stacking in the graphene layers is random with
respect to the substrate. Moreover, we find that the spot intensities are
weaker in the subsequent layers compared to the first layer, suggestive of
growth of subsequent layers from below the surface at the graphenesubstrate
interface.
1. K. McCarty, P. Feibelman, E. Loginova, N.C. Bartelt, Kinetics and
Thermodynamics of Carbon Segregation and Graphene Growth on Ru
(0001). Carbon 2009, 47(7):1806-1813.
9:00am TS4-1-4 Self-assembled monolayer nanodielectrics for lowpower
graphene electronics, T. Anthopoulos
(thomas.anthopoulos@imperial.ac.uk), F. Colleaux, C. Mattevi, Imperial
College London - South Kensington Campus, UK, M. Chhowalla, Rutgers
University, US INVITED
Succesfull development of graphene based nano- and macro-elenctronics
would require not only high quality graphene but also the design of low
power devices and integrated systems. Energy consumption has become
among the three top challenges of current, as well as future technologies, as
stated in the International Technology Roadmap for Seminconductors. To
this end, the introduction of high-capacitance gate dielectrics in field-effect
transistors has been considered a vaiable route to decrease the operating
voltages and thus the overall power dissipation. In this presentation I will
discuss the development of low operating voltage (