Ten-year experience on the production of thin films by vapor phase deposition (CVD and MOCVD) has allowed to apply this process to the growth of alumina and chromia films as protective coatings against wear and corrosion. In particular well compact and adherent deposits of amorphous alumina have been obtained on metallic surfaces. The coatings result transparent, therefore they leave unchanged the aspect of the metallic surfaces, while they are able to protect the surfaces against wear and corrosion. In fact a significative increase of the surface hardness has been obtained both for AISI 304 ( 3,84 GPa for uncoated AISI 304 and 10,89 GPa for the coated system) and for brass (2,16 GPa for the uncoated metal and 11,45 GPa for the alumina/brass system). Electrochemical measures of surface impedance, performed by the Department of Chemistry of the university Ca' Foscari in Venice, were used to evaluate the corrosion performance of the alumina deposits. The results confirmed that the alumina coatings ensure a good corrosion protection of the surface of AISI 304 and of the brass towards very aggressive acidic solution (aerated 1N H2SO4 at 25°C) and towards seawater environments. Chromia coatings on stainless steel have been also obtained by the MOCVD process. In this case varying the deposition parameters and using different precursors we have optimised the process to obtain pure and crystalline chromia with hexagonal eskalonite structure. This coating on AISI 304 has a good surface hardness equal to 25 GPa and a good adhesion determined through measures of nanoindentation and scratch test respectively.
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