Plasma Surface Engineering Laboratory

The research activities are mainly related to the thin coatings deposition by PVD methods. A duplex deposition technique (CMSII) combining DC magnetron sputtering process and ion implantation has been developed in PSE Laboratory. The CMSII technique involves simultaneous magnetron sputtering and high energy ion bombardment. In the deposition process three types of low pressure electrical discharges (magnetron discharge, DC bias discharge and high voltage pulse discharge) are superposed. The plasma ions from the magnetron and bias discharges are accelerated during the high voltage pulses and strike initially the substrate and then the coating itself during its growing with energies of tens of keV. By this method, nano-structurated coatings such as ZrN, Zr(C,N), ZrC, VN, V(C,N), nc-Ti2N/nc-TiN, etc., with very good properties in terms of thickness, hardness and thermo-mechanical characteristics have been produced. The application area of these coatings includes cutting tools, punches, dies, hydraulic parts, etc.

A special attention was devoted for synthesis a-C:Me films designed for applications demanding low friction coefficients (a-C:W; a-C:V).

An application of particular importance for this technique is the tungsten coating of CFC (Carbon Fiber Composite) and FGG (Fine Grain Graphite) tiles for the first wall in fusion nuclear devices (JET and ASDEX Upgrade tokamaks).

W-Mo Marker W-Mo Marker-2

W-Mo detail

SEM images of a W and of a W/Mo marker coatings deposited on CFC substrate

In order to assess the coatings resistance to high heat fluxes (HHF) and to get a fast feedback concerning the thermo-mechanical properties of the W coatings, a high temperature test facility (HTTF) was built at INFLPR. The heating is performed by an electron gun with the following operating parameters: the accelerating voltage 20 keV, the beam current 150 mA and the beam diameter ~16mm. The equipment operates in pulsed regime with a pulse duration between 1-999 s and interpulse duration 1-999 s. In this way it is possible to test the coated samples to a large number of pulses (a few thousands), relevant to normal operation of a fusion device. The power density can be increased up to 10 MW/m2 allowing the testing of the coatings up to a temperature of 2000 0C.