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Project 3

"Surface Improvement: Coatings from cluster materials"

EST Project MEST-CT-2005-020986

Cluster Chlor (Einkristalldifraktometer Messung)

Fellow  Dipl.-Ing. Ester Sala Bosch
Foreseen duration 36 months
Start Date 15.10.2006
End Date 15.10.2009
Ministering Institut University of Rostock, Institute of Chemistry,
Inorganic Chemistry (Prof. Köckerling)
Project Images
Figure 1. Scheme of the main steps of the project. After the preparation two main steps, the precursor
deposition and the cluster bond breaking.

Figure 2. Overview of the particle formation stages of A4[Nb6Cl18] (A = Na, K, Rb) on different surfa-
ces, adapted from the work of Zinke-Allmang et al.[1] SEM images of the different growth stages. The
used substrates were Aluminium (spinodal), Copper (initial and diffusive growth), glass (coalescence,
break-up and Ostwald ripening) and Zirconium (nucleation).
[1] M. Zinke-Allmang, L.C. Feldman, M.H. Grabow, Surf. Sci. Rep. 1992, 16, 377.

Figure 3. EDX-mapping micrographs: a) and b) K4[Nb6Cl18] on copper substrate, deposition using
spread technique; c) and d) Niobium particles on a copper substrate. Deposition of the K4[Nb6Cl18]
precursor using spread technique. Breaking of the cluster bonds using heating technique, 1h at 900°C
Project Goal Induce surface modification on different substrates using metal nanoparticles coming from cluster materials.

Since the beginning of the study of the cluster chemistry,[1] increasing interest has been dedicated to group 5 elements and their capability to form metal clusters.[2-4] Besides, some studies on the properties of clusters on inert surfaces as heterogeneous catalysts have been performed.[5,6] In the case of Nb and Ta, the experiments performed by Kamiguchi et al.[7] showed that crushed crystals of halide clusters of these elements can be used to catalyze the production of some organic compounds.

On other terms, it is well known that the metals in these groups have refractive properties such as high melting point, hardness and tensile strength. In this work novel uses of the niobium cluster halides as precursors to obtain elemental niobium particles on metallic and non-metallic surfaces are studied. This niobium coating is intended to modify the properties of the bulk material used as substrate, especially mechanical properties (hardening coatings) and thermal properties (thermo barrier coatings).

The deposition of the metal on the surface takes place in two phases. In the first phase, the cluster material from the solution is deposited on the substrate. Several deposition techniques are used for this purpose, but the most promising ones are the direct spreading of the solution on the surface and the submersion of the pieces in the solution in a sealed tube under vacuum. In the second phase, the cluster bonds are broken in order to obtain elemental niobium particles on the surface, which must be done with the help of energy.

[1] a) F. A. Cotton, Inorg. Chem. 1963, 2, 1166; b) F. A. Cotton, Inorg. Chem. 1964, 3, 1217.
[2] A. Simon, H. G. Schnering, H. Wöhrle, H. Schäfer, Z. Anorg. Allg. Chem. 1965, 339, 155.
[3] P. J. Kuhn, R. E. MaCarley, Inorg. Chem. 1965, 4, 1482.
[4] P.B. Fleming, L.A. Müller, R.E. McCarley, Inorg. Chem. 1967, 6, 1.
[5] M. Ichikawa, in Metal Clusters in Chemistry, Vol. 3 (Eds: P. Braunstein, L.A. Oro, P.R. Raithby), Wiley-VCH, Weinheim, Germany 1999, Ch. 4.1.
[6] D.S. Shephard, T. Maschmeyer, G. Sankar, J. M. Thomas, D. Ozkaya, B. F. G. Johnson, R. Raja, R. D. Oldroyd, R. G. Bell, Chem. Eur. J. 1998, 4, 1214.
[7] a) S. Kamiguchi, M. Watanabe, K. Kondo, M. Kodomari, T. Chihara, J. Molec. Cat. A 2003, 203, 153; b) S. Kamiguchi, S. Takaku, M. Kodomari, T. Chihara, J. Molec. Cat. A 2006, 260, 43.
Papers in international peer reviewed conferences,
Participation in workshops, summer schools, study visits and tutorials,
  • Colloquium of the north German Inorganic Chemistry PhD Students, Bremen (Germany), 26th to 28th September 2007. Poster presented “Metal Nanoparticles made from Deposited Cluster Materials”
  • Spring symposium of the Young Chemists Forum of the German Chemical Society, Rostock (Germany), 26th to 29th March 2008. Poster presented “Surface Improvement: Metal Nanoparticles made from deposited Cluster Materials”
  • First Conference on Functional Nanocoatings, Budapest (Hungary), 30th March to 2nd April 2008. Poster presented “Surface Improvement: Metal Nanoparticles made from deposited Cluster Materials”
  • Junior Euromat. Lausanne (Switzerland), 14th to 18th July 2008. Poster Presented “Surface Improvement: Coatings from cluster materials”
  • Colloquium of the north German Inorganic Chemistry PhD Students, Braunschweig (Germany), 25th to 26th September 2008. Oral Contribution “Surface Improvement: Coatings from cluster materials”
  • AG Prof. Burkel (Physics)
  • AG Prof. Lochbrunner (Physics, Laser, UV-Vis spectrometer)
  • AG Prof. Jonas (Medicine, SEM)
  • AG Prof. Gerber (Physics, SEM)
Using Devics and Instruments
  • Scanning Electron Microscope (AG Jonas, AG Gerber)
  • Light Microscope
  • UV-Vis spectrometer (AG Lochbrunner)
  • Femtosecond pulsed laser (AG Lochbrunner)
  • X-ray powder camera
  • Single crystal diffractometer