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An X-ray diffraction methdology for the microstructural analysis of nanocrystalline powders: application to cerium oxide
No full textThe microstructure and mechanical properties of Fe-Cu materials fabricated by Pressure-less Shaping of nanocrystalline powders
No full textThe microstructure of Fe-40%wtCu nanocrystalline powders, prepared by mechanical alloying, was studied before and after the consolidation process. Pressure-less-shaping (PS) was used to consolidate the powders.
The PS technique, similar to metal injection moulding (MIM), does not require external pressure in order to fill up the mould. The key factor of the process of consolidation is the use as binder a hybrid inorganic–organic monomer, formed by the reaction of zirconium propoxide and 2-hydroxy ethyl methacrylate. This type of monomer, mixed with the metallic powders, formed slurry having low viscosity, which was easily poured into mould. The binder stiffened upon polymerization. Some pieces were produced through debinding and sintering, both performed under inert atmosphere in order to avoid metal oxidation. Different microstructure and density were observed depending on the maximum sintering temperatures, ranging from 904 to 1,120 C. In the sample sintered at 1,120 C, the crystalline domains of the copper phase were of about 40 nm
Microstructural and thermal characterization of neolithic ceramics
No full textThe aim of this research was to characterize some Neolithic ceramic finds collected during an excavation carried out at Lugo di Grezzana (Verona, Italy). Pottery shards with different paste and tempers were analyzed to better understand the manufacturing and firing technologies used for their production. Another task of the study was to determine whether highly refined artefacts, found in the site and resembling figulina-type ceramics, were of local production or imported from other places in the north of Italy, where the production of this sort of product has already been unambiguously assessed. Several results emerged from this investigation, providing indications on the finds from this Neolithic settlement and, therefore, on the technological expertise achieved by the primitive community. Moreover, a comparative study carried out on refined ceramic products found in Lugo and genuine figulina items from other northern Italian sites suggests that no trading exchange and commercial routes existed among those primitive communities
Electrochemical behaviour of ZrO2 pre-treatments deposited with sol-gel technique on AA2024 aluminium alloy
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