Sputtering: A Versatile Technology to Deposit Multifunctional Protective Coatings.

Among the vast array of technologies available for surface modification of materials, sputtering emerges as one of the most versatile methods through coating deposition. Included in the family of physical vapor deposition (PVD) techniques, sputtering allows the production of coatings with a great variety of characteristics, based on a bottom-up approach that forms coatings from individual species (atoms or ions). This versatility is achieved by controlling: (i) the layer architecture, from monolithic to multilayers, (ii) the structures, from amorphous to nanocrystalline or nanocomposite, until highly crystallized, including epitaxial; (iii) the morphologies, from very porous through columnar or zig-zag to very dense and featureless; (iv) the chemical composition, allowing the deposition of metallic, polymeric, ceramic or composite materials types. In this paper, after a brief introduction of sputtering as a deposition technology, we will review the application of sputtering for depositing protective coatings to which an extra functionality is provided: (a) aesthetic color; (b) high-temperature lubrication; and (c) temperature sensing ability.