A new way for the aesthetical enhacement of ceramic materials: decorative PVD (Physical Vapour Deposition) films

摘要

In the PVD (Physical Vapour Deposition) techniques, atoms or groups of atoms, which are going to build up the film, are carried into gaseous form by means of two main physical processes, thermal evaporation or sputtering. The deposition takes place in vacuum chambers, appropriately equipped with precise sensors to control the process, at pressures which can vary between 10~(-2) and 10~(-5) mbar, according to the different materials to be deposited or coated. PVD technologies are commonly used to manufacture films, whose thickness ranges from few angstrom ("mono-layers") to some microns. They can be used in many applications with dissimilar purposes in very different industrial fields, from advanced mechanics to the "state of the art" mi- croelectronics. They are becoming more and more used because of the "day by day" higher demand of high performance engineered materials, which must show many multiple properties at the same time (corrosion resistance, excellent mechanical responses at high temperatures and specific optical, electric and magnetic characteristics), sometimes even "contrasting", such as hardness and toughness. Thanks to the versatility of PVD, it is possible to virtually deposit any materials (metals, alloys, ceramics,...) on any substrate. The rate of deposition can vary from few tenth of A per minute up to tenth of microns. These latter values are possible if electron beams are used to heat up the coating material (usually in the form of solid state targets).