DISPOSITIF POUR GENERER UN PLASMA FROID DANS UNE ENCEINTE SOUS VIDE ET UTILISATION DU DISPOSITIF POUR DES TRAITEMENTS THERMOCHIMIQUES

摘要

#CMT# #/CMT# In apparatus for generating cold plasma in an evacuated vessel using a cathode body (1) with hollow plasma confinement chambers (1a), each chamber is associated with a magnetic field source (2) causing electrons to rotate around its lines of force. The cathode body is provided with a cooling fluid circulating element (3) to extract heat generated by the intense ionic bombardment in each of the hollow chambers. #CMT#USE : #/CMT# The use of the apparatus is claimed in thermochemical treatments, specifically for nitridation. More generally the apparatus creates active species independently of the substrate temperature, for use in surface treatments such as discharge, thermochemical treatment (e.g. nitridation or cementation), activation, grafting or cleaning. #CMT#ADVANTAGE : #/CMT# High power cold plasma is generated in a simple, effective and reliable manner. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The figure shows a sectioned view of the cold plasma generation apparatus. 1 : Cathode 1a : Hollow chambers, for plasma confinement 1b : Holes 2 : Magnets, as magnetic field source 3 : Cooling fluid circulating element 3a : Central groove 7 : Clamping screw 8 : Toric joint #CMT#CHEMICAL ENGINEERING : #/CMT# Preferred Apparatus: The magnetic field sources (2) are magnets, preferably located around and parallel to hollow chambers (1a) in the form of openings. The magnets have the same North-South orientation, or are oriented in a random or alternating manner. Specifically the magnets are located in holes (1b) in communication with the cooling fluid, with the hollow chambers opening from the evacuated side into the vessel. The cooling fluid circulation element (3) is independent of, and fixed in a sealed manner into, the cathode body (1); or alternatively the fluid circulation element and cathode body form a unitary structure. The fluid circulation element and cathode body are of non-magnetic, conductive material. The magnets are especially permanent magnets, in the form of cylinders fixed in the holes (1b) in the cathode body.