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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Characterization and modification of the mechanical and surface properties at the nanoscale

Tam, Enrico 03 December 2009 (has links)
In the past two decades much effort has been put in the characterization of the mechanical and surface properties at the nano-scale in order to conceive reliable N/MEMS (Nano and Micro ElectroMechanical Systems) applications. Techniques like nanoindentation, nanoscratching, atomic force microscopy have become widely used to measure the mechanical and surface properties of materials at sub-micro or nano scale. Nevertheless, many phenomena such us pile-up and pop-in as well as surface anomalies and roughness play an important role in the accurate determination of the materials properties. The first goal of this report is to study the infulence of these sources of data distortion on the experimental data. The results are discussed in the first experimental chapter. On the other hand, conceptors would like to adapt/tune the mechanical and surface properties as a function of the required application so as to adapt them to the industrial need. Coatings are usually applied to materials to enhance performances and reliability such as better hardness and elastic modulus, chemical resistance and wear resistance. In this work, the magnetron sputtering technique is used to deposit biocompatible thin layers of different compositions (titanium carbide, titanium nitride and amorphous carbon) over a titanium substrate. The goal of this second experimental part is the study of the deposition parameters influence on the resulting mechanical and surface properties. New materials such as nanocrystal superlattices have recently received considerable attention due to their versatile electronic and optical properties. However, this new class of material requires robust mechanical properties to be useful for technological applications. In the third and last experimental chapter, nanoindentation and atomic force microscopy are used to characterize the mechanical behavior of well ordered lead sulfide (PbS) nanocrystal superlattices. The goal of this last chapter is the understanding of the deformation process in order to conceive more reliable nanocrystal superlattices.
2

Characterization and modification of the mechanical and surface properties at the nanoscale

Tam, Enrico 03 December 2009 (has links)
In the past two decades much effort has been put in the characterization of the mechanical<p>and surface properties at the nano-scale in order to conceive reliable N/MEMS<p>(Nano and Micro ElectroMechanical Systems) applications. Techniques like nanoindentation,<p>nanoscratching, atomic force microscopy have become widely used to measure<p>the mechanical and surface properties of materials at sub-micro or nano scale. Nevertheless,<p>many phenomena such us pile-up and pop-in as well as surface anomalies<p>and roughness play an important role in the accurate determination of the materials<p>properties. The first goal of this report is to study the infulence of these sources of data<p>distortion on the experimental data. The results are discussed in the first experimental<p>chapter.<p>On the other hand, conceptors would like to adapt/tune the mechanical and surface<p>properties as a function of the required application so as to adapt them to the industrial<p>need. Coatings are usually applied to materials to enhance performances and reliability<p>such as better hardness and elastic modulus, chemical resistance and wear resistance.<p>In this work, the magnetron sputtering technique is used to deposit biocompatible thin<p>layers of different compositions (titanium carbide, titanium nitride and amorphous<p>carbon) over a titanium substrate. The goal of this second experimental part is the<p>study of the deposition parameters influence on the resulting mechanical and surface<p>properties.<p>New materials such as nanocrystal superlattices have recently received considerable<p>attention due to their versatile electronic and optical properties. However, this new<p>class of material requires robust mechanical properties to be useful for technological<p>applications. In the third and last experimental chapter, nanoindentation and atomic<p>force microscopy are used to characterize the mechanical behavior of well ordered lead<p>sulfide (PbS) nanocrystal superlattices. The goal of this last chapter is the understanding<p>of the deformation process in order to conceive more reliable nanocrystal<p>superlattices. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

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