PVD stands for “Physical Vapour Deposition”. PVD processes are environment-friendly because no waste gases or hazardous waste are produced.
In PVD technology, a base material (often a metal) is vaporised in a vacuum. This metal vapour is then deposited on the parts to be coated (substrate), forming the coating which is often just a few micrometres thick. These PVD coatings can lend special properties, for example a superior appearance thanks to a special colour, an electrically conductive surface as a shield against electromagnetic fields, excellent wear resistance thanks to high hardness, etc.
During evaporation, thermal energy is applied to the base material by means of an electron beam or a heating spiral. As a result, this base material, frequently a metal, is vaporised and moves towards the substrates in the form of tiny particles (molecules, clusters). Depending on the requirements placed on the coating, small quantities of process gases are added and react with the metal vapour. The vapour condenses on contact with the substrates, forming the coating.
In the sputtering process, electrical and magnetic fields are used to produce argon ions (plasma) above the plate-shaped base material (target). These positively charged ions (Ar+) are accelerated towards the target which is connected as the cathode, causing the release of minute particles (molecules, clusters) as a result of the impact. These particles react with other process gases such as nitrogen or oxygen and move as a vapour towards the substrates to be coated. The connection of an additional electrical field (bias) further influences the deposited coating and controls its properties.
In the arc vapour deposition process, the plate-shaped base material is connected as a cathode. A wire connected as the anode touches the plate briefly, initiating an arc. The root of the arc now moves around on the surface of the plate, causing localised vaporisation of the base material in response to the high energy density. A highly concentrated plasma is produced in the form of a vapour beam, through which the substrates are drawn. The addition of process gases such as nitrogen or carbon-containing gases and the connection of an additional electrical field (bias) ensure that the deposited coating features the desired characteristics.