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November 13-14, 2017 Paris, France
5th International Conference on
PLASMA CHEMISTRY AND
PLASMA PROCESSING
Journal of Biotechnology and Phytochemistry
Volume 1, Issue 2 Plasma Chemistry 2017
Structure and thermodynamics of Mg-Ti-H films
deposited by microwave plasma-assisted co-sputtering
Daniel Fruchart
Neel Institute – CNRS, France
Introduction: Hydrogen storage ennobles renewable and
intermittent energy objectives thanks to electrolysis from wind-
mill and PV. MgH2 is performing since Mg abundance, low cost,
7.6 w% H-storage capacities. However, sorption kinetics remain
slow, unless adding specific additives in dedicated nanostructures.
Early transition metals, not forming stable compounds with Mg
can act as efficient catalyst. Thin films deposited by co-sputtering
Mg and Ti were hydrogenated/dehydrogenated revealing original
nanostructures, mechanisms of reaction, but some metastability
of h-Mg-Ti alloy.
Methods: We operate direct combinations of Mg, Ti and H in
a single-step process, using the microwave reactive plasma-
assisted co-sputtering technique. Mg-Ti-H films with Ti contents
0 ≤ at. %Ti < 20 were investigated by XRD, SEM, TEM-EDX for
morphology, crystal structure, composition and distribution
of elements. Ti-poor films (at. %Ti≤0.45) exhibit the β–MgH2
phase mainly, with a dense microstructure and discontinuous
columnar grains. Films with intermediate Ti-contents (2.7≤at.
%Ti≤6.6) exhibit β–MgH2, metastable γ–MgH2 and h-Mg-Ti
phases in different proportions, with well-developed columnar
grains. Films with Ti-contents >10 at. % form fine grain
amorphous/Nano-crystalline structures.
Results: Ti content reveals critical in tuning the functional
properties of magnesium hydride. The structure and morphology
of different films were investigated after dehydrogenation
comparison made with initial hydrogenated states using XRD
and SEM. The thermal stability was studied by TGA and DTA
coupled with mass spectrometry.
Conclusion: In comparison with monohydrides MgH2- and
TiH2-films, lowest desorption temperatures of Mg-Ti-H films
were observed for ~4.8 at. %Ti. The as-deposited h-Mg-Ti phase
appears stable upon hydrogenation/dehydrogenation delivering
comprehensive approaches on easier Mg ↔ MgH2 reactions.
Biography
Daniel Fruchart has completed his MSc in mathematics at Lille University and;
completed hab.D physics from Joseph Fourier University, Grenoble. He has
worked as the Director 1 at CNRS from the year 1995-2009 and he took the
responsibility of research group at Institute Neel (1982-2009) for 8-12 Staffs,
2 post docs, 10 PhD students, 1 Engineer. He is the founder and Research
manager to MCMF department at Neel Institute since 2008 to 2013. He has
published more than 820 reviewed papers and has 16 book contributions
with H factor 42, RS citations more than 8800.His interests include magnetic
materials, metal-hydrides, synthesis/metallurgy, thin films, neutron scattering,
x-ray spectroscopy and group theory.
Daniel Fruchart, J Biot Phyt 2017