2009 R&D 100 Winner
The fatigue strength of aero engine compressor blades and vanes has been degraded because of their high processing temperature and other reasons. Even with the current technologies, only a small number of components are coated. This could change with the implementation of a new process, Plasma Enhanced Magnetron Sputtering (PEMS) Technology for Depositing Super-hard, Ultra-thick Nanocomposite Coatings, which has been developed by Southwest Research Institute, San Antonio, Texas. The PEMS process is based on, but different from, conventional magnetron sputtering in which a global plasma is introduced. It allows thorough cleaning of the component surfaces to remove oxide and surface contaminants before the coating deposition, ensuring the coating adheres to the substrate. During the deposition process, this global plasma enhances the ion bombardment of the depositing coating. The ion flux to the substrate can be up to 25 times higher than that obtained using conventional magnetron sputtering. As a result, very dense and very hard coatings can be achieved. In addition, because the high ion flux is used, no external heaters as in the conventional physical-vapor deposition systems are needed, allowing the deposition temperature to be reduced. Low temperature deposition also reduces the thermal stress to as low as 250°C, which is a cause for coating delamination, component distortion, and reduced fatigue strength.
Technology
Sputtering process
Developer
Soutwest Research Institute
