Physical Vapour Deposition (PVD) is a purely physical coating process. Under a high vacuum, atoms and atomic clusters are stripped away from (usually) metallic targets via thermal vaporisation, ion plating or sputtering. This metal vapour can be applied directly to a component (metallising) or it combines with a reactive gas added (generally nitrogen or carbon-containing gases). Complex chemical compounds are then formed. The layer thicknesses of these hard materials can be adjusted between 1 nm and 5 µm. Both the coating system and thickness are defined based on the specific customer requirements.
The binding of the coating to the substrate material, the most challenging step in the process, is achieved through targeted activation of the surface. Depending on the desired end result, a wide range of materials can be used as the target. Titanium, chromium, or copper are just a few examples. Conversely, a wide range of substrates can also be coated: Metals, as well as ceramics, glass or plastic, but textiles too. Science and industry are currently driving the development of biocidal layers, such as those with complex copper systems, in order to benefit from their anti-viral and anti-bacterial properties. Another example application is the coating of plastic bearing bushes with a carbon-manganese disulphide layer, to improve their wear-resistance and coefficient of friction.
The possible applications are virtually unlimited.
The importance of copper as a biocide has been known for a long time, as it is harmful to bacteria and in viruses even in small doses. Copper compounds allow RUBIG to produce biocidal coatings and use them in versatile ways. With RUBIG AnitViralCoating, a surface technology has been created in which the effect against bacteria and viruses is generated by the oxidation of the surface.
The PVD processes developed at RÜBIG are based on ablation of the atoms using magnetron sputtering. The argon provided for atomisation is accelerated onto the target material by means of an externally applied voltage. The magnetic field formed forces the ions into a spiral-shaped track and provokes more frequent collisions with the target. As a result, more atoms are released in the target surface. The force transferred to the accelerated atom by the argon remains unaffected in the high vacuum. This allows the target atoms to move across the gap to the substrate. Through targeted rotation of the components around multiple axes, a homogeneous layer (thickness) is produced on the substrate.
The process takes place at low temperatures. This means there is little or no distortion of the components. Also in the case of plastic: the surface activation takes place at a maximum of 100°C and of course in plasma or with the aid of an ion source. RÜBIG PVD systems allow exact adjustment of material properties such as hardness, adhesion, service life, or mechanical properties. A suitable process visualisation allows the relevant parameters to be displayed in a structured form. The systems are also equipped with a safety concept which has been custom-developed in-house. This initiates interlocking and cooling of the system should the supplies of power or other media (gases) fail. In addition, the technology impresses with its environmental performance and cost-efficiency, particularly when transitioning to series production.