Abstract:
A black second layer containing xylene, petrol and tungsten powder is provided on an unsintered first insulating layer of aluminium oxide and polyvinyl acetate of a filament of an indirectly heated cathode.
Abstract:
A helically wound V-shaped bent reciting wire or bifiller wound heating wire for an indirectly heated cathode is previously dipped in a liquid or connected anaphoretically and then covered in an electrophoresis bath with an insulating layer.