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PVD Coating

PVD Coating

Date posted: June 13, 2017 // Coating

The term physical vapour deposition, which is commonly abbreviated to PVD, describes a variety of methods used to create a thin film or coating of given material, such as a refractory metal or ceramic. During these procedures, the selected material is transformed from its condensed phase to a vapour state suitable for spraying and, upon contact, it condenses once again to form a thin, solid film on the surface of the item to be treated. This type of process is normally used to modify some physical property of the targeted surface, such as increasing its resistance to scratching and to the possible ill effects of heat or corrosion.

Of the half dozen processes included under the umbrella heading of physical vapour deposition, sputtering and evaporation are probably the two used most widely. In the first of these processes, a plasma discharge is localised by means of a magnetic field, and used to bombard a suitable source material. This causes it to sputter, and the resulting vaporised material can then condense as a thin film on the targeted surface. This form of PVD coating is the technique commonly used to protect the surface of solar panels that would otherwise be damaged quite quickly by their constant exposure to the wear and tear of the elements.

Generally better suited to the treatment of smaller objects, the evaporative process uses high temperatures generated by electrical resistance in a vacuum in order to vaporise the protective material and thus prepare it for deposition on to the surface of the substrate. Among the other physical vapour deposition techniques, one involves the use of an electric arc to convert the source material into an ionised vapour that can then be coated on the workpiece, while another relies on a high-power laser beam, which acts to ablate the selected material into its vaporised state.

The choice of techniques is determined by a number of factors, including the nature of the intended PVD coating material and the size and composition of the material that is to be coated. In addition to ceramics, the bulk of the materials used for this purpose are refractory metals. These include chromium, molybdenum, niobium, tantalum, titanium, and tungsten, often in the form of their alloys.

Specialising in the supply of these materials and the equipment required for their use, the Midrand-based company LIT Africa is a long-established local leader in this field as well as in the supply of specialised glass products. Backed by more than half a century of experience, the company is dedicated to product and service excellence, sourcing all high-quality PVD coating requirements exclusively from the industry leaders.