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Advanced Processing and Characterisation of Micro and Nano Composites

Final Report Summary - NANOCOM-NETWORK (Advanced Processing and Characterisation of Micro and Nano Composites)

Advanced Processing and Characterisation of Micro and Nano Composites - NanoCom network.

"NanoCom-Network" was designed to develop cooperation between European and Latin American institutions in the field of advanced processing and characterization of micro and nano composites. The following institutions participated in the network: Saarland University (UdS, Germany), Vienna University of Technologiy (TUW, Austria), European Synchrotron Research Facility (ESRF, France), Helmholtz Zentrum Berlin (HZB, Germany), Centro Atómico Bariloche (CAB, Argentina), Universidad Nacional de Río Cuarto (UNRC, Argentina), Universidade de São Paulo (USP, Brazil) and Universidad de Concepción (UdeC, Chile).
The duration of this IRSES project was from June 2010 until May 2013. During this period, a total of 38 exchanges were carried out comprising a total amount of 56 months and a total budget of about 88.000€. As a result of this collaboration 18 peer review papers were published and 6 more are currently under revision. 9 contributions were also published in conference proceedings.

The following scientific achievements were obtained during the project for the different studied topics:

• CNT-reinforced metal matrix composites: we were able to successfully manufacture bulk composites via powder metallurgy, which showed outstanding thermo-mechanical, mechanical and thermal properties compared to the pure metal. The electrical properties and sparking behavior of the composites was lower as expected, probably due to a strong reagglomeration of the CNTs.

• Advanced design of Al-MMC and the study of the effects on the interfaces: different Aluminum-based MMCs (Al-Al2O3; Al-TiB2; Al-Zn; Al-Saffil) were successfully manufactured by different routes including liquid, semisolid and solid state processing. The processing parameters where optimized for the different systems, in order to obtain enhanced the mechanical properties. These were determined meanly by a self-developed Small Punch Test technique. The interface between reinforcement and matrix was studied by TEM in order to analyze the stability of the phases.

• Advanced production and characterization of nano-structured bulk metal-ceramic composites: Fe matrices reinforced with WC was produced by sol-gel and by aqueous technique. The WC-grains presented sizes of several µm. The technique is now under optimization in order to reduce the size of WC-grains in order to achieve sub-µm sizes, which should improve the properties of the material.

• Advanced production and characterization of nano-structured coatings: Titanium carbonitride (TiCN) coating layers with star-shaped crystallite morphology were produced by chemical vapor deposition. The formation of such crystallite morphology was investigated and explained. This graded layers showed outstanding mechanical properties for the use as coatings for cutting tools.
For improving the adhesion of the coating to the substrate, steel substrates were pretreated by increasing the amount of defects. The modification was done by Xe-peening. Synchrotron analysis showed that plasma nitriding reduces the compressive residual stresses of the TiN film, whereas Xe+ bombardment prior to plasma nitriding causes increased residual stresses in the TiN film.

• Modern characterization of MMC/3D characterization of MMC: The focused ion beam nanotomography technique, that allows direct three-dimensional investigations in materials, was applied for studying features as small as 10 nm, which is close to the resolution limits of this technique. Through this, quantitative characterization of mesopores in carbon materials as well as composites with reinforcements in the form of nanowires was achieved.
FIB-sample preparation for Atom Probe as well as for TEM was optimized for the different composite materials. Specially for searching very low amounts of elements (e.g. Sr in AlSi and B in Steel) interfaces and precipitates. An in situ thermo-mechanical tester is being developed for its use in synchrotron equipment.

Additionally to the original planned activities, several new cooperation lines where started within the project, as described as follows:

• MMC reinforced with Nanowires for electrical applications (UdS, UNRC).
• Development of structural light metals (Mg-, Ti- and Al-alloys) (TUW, USP).
• Crystallization of Iron Phosphate Glasses (CAB, UdS).
• Characterization of conductive polymers in hydrogels (UNRC, UdS).
• Polymer/CNT composites for gas sensors (UNRC, UdS, Universidad de Buenos Aires, Arg.).
• Laser synthesis of noble metals nanoparticles (UNRC, UdS).
• APT characterization of heat resistant steel (UdeC, UdS).
• Characterization of CuZn nanowires (UdS, CAB).
• Surface pre-treatment of steels for coating deposition (Xe-Ion, plasma nitriding) (USP, Sandvik Coromant R&D).
• Development of instrumentation for in-situ mechanical loading (USP, ESRF, TUW).
• Effect of hot compression on microstructure and crystallographic texture of nanostructured compacted aluminium powders (USP, TUW).
• Characterization of hard coatings (Sandvik Coromant R&D, Sweden, Pontificia Universidad Catolica de Chile, UdS, HZB).
• Surface modification of stainless steel by electrolytic plasmas (UdeC, UdS): see (Gallegos et al 2012).