The Peer review has evaluated this group as Good
Starting form the tradition of Prof. Roberto Piontelli on the electrochemistry of metals (first world laboratory to use single crystals for electrokinetic and structural studies), the group has developed a rational methodology to understand how surface technology processes occur and how it is possible to optimize them, with important contributions in many different, but related fields. It has become a reference group for the Italian and European industry in the field of metallurgical coatings, with many contacts to support SMEs working in the field (about 4000 in Italy, 2% of Italian GDP). The main points of the researches regarded the following: 1. Metal structures and electrokinetics of electrochemical deposition ECD (5,6,7,11); the knowledge, developed by studying the mechanisms of electrodeposition processes and the structure of the resulting electrodeposits, was utilized to obtain controlled crystal growth and, in particular, to obtain mono-oriented deposits, with interesting application for wear resistance and magnetic applications; amorphous and nanocrystalline deposits were studied and alternatives to plating processes under discussion for ecological problems (chromium VI and cyanides) were proposed. 2. Autocatalytic chemical deposition ACD of NiP and CoP (4); the most appreciated mechanism of the nickel ACD process, based on hydrolized nickel species reacting at the surface was introduced by this group, that has continued to develop applications of Ni and Co ACD, especially for electronics. 3. Alloy and composite electrodeposition (2,3); the deposition of many different alloy systems with interesting applications was studied, such as IB group metal with tin, ZnMn for tyre cords and MnCu as alternative to Zn; the phase structures obtained were interpreted with a thermodynamic approach, from the free energy composition phase diagram, calculated without presence of intermetallic phases having ordered structures with very long range order; an analogous field of application regarded composite coatings, with important achievements regarding the possibility of codepositing carbon nanotubes and submicro ceramic powders and proposing these coatings as alternative to chromium electrodeposition. 4. Magnetic thin and thick layers (1,8); the group is well known for the studies on the electrodeposition of hard CoPt layers for magnetic recording and for permanent micromagnets, with possible application in MEMS and others; the researches were extended to layers for giant magnetoresistance application and to very thin soft magnetic films (in collaboration with IBM Watson Research Center) for magnetic field shielding and better definition of the magnetic transitions. 5. Anodization of light alloys; templates of alumina and titania were investigated from a fundamental point to interpret the self-ordering mechanisms arising in electrochemical systems, far from equilibrium, and because they are suitable materials for a variety of nanotecnological applications; in the field, new techniques were found by the group for the fast synthesis of ordered templates. Also the treatment of magnesium alloys by sparking anodization was examined; this technique was used as a pre-treatment for organic coatings deposition, by paintings or with sol-gel layers. 6. Diamond Like Carbon DLC deposition (9,10); studies regarded plasma-assisted vapour deposition techniques, investigated for wear-resistant coatings and functional layers; DLC coatings were deposited by a non-conventional PACVD process and an outstanding combination of high hardness and strong adhesion has been achieved, even in heavily doped films; functional layers were prepared by magnetron sputtering and a deposition process for coating steel cord in the automotive industry was patented. 7. Metallization of semiconductors; the reducing behaviour of elemental silicon toward noble metal ions in aqueous solutions containing fluoride ions has long been known. The group in collaboration with University of California at Berkeley studied the conformal deposition of thin metallic films on silicon and germanium by galvanic displacement for applications in MEMS technology. Together with the work on galvanic displacement of films, deposition of Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta” – Research Assessment Excercise 2003-2006 96 clusters by this technique from micro-emulsions was developed and applied to microreactors for hydrogen production. 8. Corrosion of stainless steel in seawater (12); evaluation of stainless steel corrosion in seawater was carried out by employing a statistical approach. Studies were performed at the Politecnico of Milan for the laboratory tests and characterization and at the MARECO (IENI-CNR) station in Bonassola (Liguria) for the exposure to natural seawater. The research was addressed specifically to the determination of the localized corrosion risk. This was achieved through a comparison between the distributions of breakdown and corrosion potentials. With the statistical approach is possible to take into account the effect of environment and design on materials corrosion resistance. The research was also focussed on the general corrosion of metallic materials, showing that localized and general corrosion can be formally unified in a stochastic approach.
Pietro Luigi Cavallotti
Luca Giampaolo Nobili