Deposition of silicon on carbon surfaces during tokamak discharges at TEXTOR-94

Silane (SiH4) has been injected directly into the scrape-off layer of TEXTO R-94 through 10 injection nozzles located at the toroidal edge of one limit er blade. The resulting temporal changes in the line emission of silicon an d carbon due to the deposition and erosion of Si are spectroscopically moni tored. Thus an erosion time can be defined, which is 5-10 seconds under ohm ic heating and 2-3 seconds for auxiliary heated I-mode similar conditions. This method offers a possibility to deposit a hard, robust coating during d ischarges and is thus a possible coating technique for steady state devices .