PROCESS FOR COATING CERAMIC FILAMENTS AND NOVEL COATED CERAMIC FILAMENTS

摘要

A process for the deposition of a carbon coating on a filament which comprises passing the heated filament through a deposition chamber containing gases which, on contact with the hot filament, deposit a carbon coating; characterised in that the deposition chamber comprises distinct first and second regions, the first region having a greater diameter than the second region. The carbon coating comprises at least two distinct layers of carbon when viewed under a scanning electron microscope, one layer presenting a visual appearance of a laminated microstructure and a second layer presenting a homogeneous visual appearance.