[Zurück]

W. Vollnhofer:
"Deposition of AlMgB14 thin films by magnetron sputtering";
Betreuer/in(nen): C. Eisenmenger-Sittner; Festkörperphysik, 2008; Abschlussprüfung: 12.11.2008.

As growing abrasion causes a drastic increase of energy consumption and costs, the development of new, high abrasion resistant, ultra-hard materials with a very low friction coefficient is important for various industrial applications in a short as well as in a long-term timescale. Because of its unique combination of mechanical, electrical and thermal characteristics AlMgB14 is regarded as a promising, cost-effective material for hard, wear abrasive protective coatings. One important aspect for producing protective thin films based on AlMgB14 is to identify proper methods to produce thin films that not only have the stoichiometry of AlMgB14 but also the appropriate microstructure. Thus the objective of this master thesis was to evaluate the possibility of AlMgB14 thin film deposition by magnetron sputtering and to examine the characteristics of the deposited films.
After installing a new magnetron sputtering source and constructing an appropriate substrate holder, AlMgB14 samples were produced using different targets. AlMgB14 targets were produced under different production parameters and the targets ´ composition was examined by X-ray diffraction (XRD). The targets with the lowest amount of impurity phases were used to deposit thin films on glass and WC-Co (~15% Co) substrates. To optimise adhesion of the films on the substrates, the substrates were differently treated before and during deposition. The effect of the substrate treatments was examined by adhesion measurements and by surface energy measurements. The deposited thin films were post annealed at different temperatures and examined by XRD, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX) and atomic force microscopy (AFM) to study the influence of temperature treatment on the composition and structure of the films. Further friction coefficient measurements were performed on bulk material as well as on deposited thin films.
Experiments showed that the 900 °C post annealed films are the most promising candidates as their stoichiometry corresponds approximately to the stoichiometry of AlMgB14. The stoichiometry of the as-deposited, the 1000 °C and the 1100 °C post annealed films differ significantly from the stoichiometry of AlMgB 14 ´ and the films are either amorphous or an undesired crystalline phase developed