Combined Magnetron Sputtering and Ion Implantation - A high energy ion assisted deposition method for producing nano-structurated coatings

The purpose of this paper is to present a high energy ion assisted deposition method and the results obtained for a few particular applications. The method, called Combined Magnetron Sputtering and Ion Implantation (CMSII), involves a periodical high energy ion bombardment of the layer during its growth and it can be seen as a Plasma Immersion Ion Implantation (PI³) process where the plasma source is a magnetron discharge. Typical parameters for the high voltage pulse discharge are: U = 30-70 kV; τ≈20 μs and f = 10-50 Hz. Using a titanium target the CMSII technique produces a featureless, extremely dense nc-Ti₂N/nc-TiN nanocomposite coating with hardness in the range of 3,000-4,500 HV0.1 and a thickness of 10-30μm. TEM analyses have shown crystallites in the range of 10-20 nm. This technique has been experimentally applied for some particular cutting tools. In some cases, the tool life has been increased by a factor of 12 as a result of coating with nc-Ti₂N/nc-TiN. Another application was the coating of CFC (Carbon Fiber Composite) substrate with a tungsten layer of approx. 10 μm, to be used as first wall in a plasma fusion device. In comparison with other PVD and CVD techniques, CMSII produced coatings with better performances in terms of resistance to intense thermal loading. Due to its capability to produce relative thick, nano-structured coatings, this technique has a significant potential for applications in hydraulics, automotive, forming and cutting tools, etc.