Micropolveri e nanopolveri: studi di processo e caratterizzazione

This PhD thesis collects the main works performed during the doctorate. The sector has been the powder metallurgy, treating both micrometric size powder that nanostructured and nano-dimensional powder. About micrometric powders were analyzed and characterized non-ferrous pow-der(copper, bronze and brass) to estimate the feasibility use in structural pieces. Moreover were produced, through an experimental atomization, two types of iron powders containing chromium, prealloyed with other elements such as nickel and molybdenum. The chromium high affinity with oxygen resulted in significant execution difficulties, which are mainly manifested in the process of reduction, which was dedicated a very significant work share. After an effective reduction laboratory-scale powders have been completely characterized. Another project was carried out on nanostructured powder on the specific sector of dia-mond tools. It 'been evaluated an innovative cobalt substitute product for use in the array of inserts of diamond grinding wheels. The latest work is part of a wider project under the Sixth Framework Programme and financed by the European Community, which provides for the use of sonoelectrochemical process for the production of nanopowders. To sum up the process it's a combination of an electrodeposition with a sonolisi, which detaches the electro-deposited metallic layer and to reduce it in the nanometric size. The laboratory scale process improvement was fol-lowed by the scale up and optimization of a pilot plant, suitable for significant metallic nanopowder quantities production.