Looking at aeronautics, mechanical engineering or packaging industry – coating does improve materials or give them extra functions. At Hannover Messe (April 4th to 8th 2011) Fraunhofer will be showing procedures, materials and methods for analysis concerning surfaces at their booth in hall 6, booth H21.
Icing keeps the cake fresh, looks nice and tastes good. But it is not necessarily needed. In other fields however coating has a very important function. Plastic antennas are solely conductive because of copper coating. With barrier coating foils can achieve better sealing. In contrast to putting the icing on a cake, it often is complicated to coat materials. Four institutes of Fraunhofer show different functional surfaces, coating methods and techniques to analyse and optimise those procedures at the surface-booth at Hannover Messe.
Carbon fibre strengthened plastics (CFKs) are high performance materials, which are extremely light and very solid at the same time. Therefore they are very interesting for aerospace. Several components have to be conductive as well – a requirement that is not completely met by CFKs. Researchers from Fraunhofer-Institute for Surface Engineering and Thin Films in Braunschweig developed a method to cover plastics with an adhesive metal coat to improve their conduction. For that some pre-treatment is necessary. First the Researchers roughen the surface of the plastic with a wet chemical etching method. This allows the metal film to adhere to the surface. Through dip coating a very thin electrically conductive film is now applied. Only with that the following galvanic coating process is possible. Using this procedure Researchers could already coat CFK-tubes with copper. Those antennas will soon transmit environment and security data from satellite “Sentinel” to the earth.
The Researchers from Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart also deal with galvanic processes. They present an electrolyte test stand at the electroplating area at Hannover Messe. This is a device to check, optimize and develop coating procedures. The testing is standardized, repeatable and very realistic. In principle the test stand resembles a little reproduced production unit. The three-dimensional test block, which gets coated, has all the problematic parts like salient angles, edges and flutes. Furthermore temperature and incident flow can be adjusted, so it resembles reality. However the previous test systems are far from reality and use for example idealised test blocks.
Electric conduction through plating is an example for functional coating, but the prospects of surfaces go even further. Some foils are coated in a way that enables them to detain a lot of steam. This is interesting because moisture affects a lot of delicate products such as pills and potato chips and furthermore highly sensitive active films in organic LEDs (OLEDs) or organic solar cells. Previously used films still allowed a few water molecules to leach. The amount differs between materials, but for a lot of applications it is really important. Researchers from Fraunhofer Institute for Material and Beam Technology in Dresden developed a method of measurement that enables us to determine the amount of water that leaches more precisely than before. The HiBarSens system is one of several exhibits at the surface-booth.
Fraunhofer-Institute for Surface Engineering and Thin Films, Braunschweig
Fraunhofer Institute for Manufacturing Engineering and Automation IPA, Stuttgart