METHOD FOR COATING METAL TO INSIDE SURFACE OF INSULATING PIPE

摘要

PURPOSE:To coat an electrode metal at a uniform thickness on the inside surface of an insulating pipe without using an aq. soln. by putting the insulating pipe consisting of ceramics, into a vessel contg. an inert gas and subjecting a desired metal as an electrode to low-pressure gaseous discharge in the insulating pipe. CONSTITUTION:A ceramic pipe 4 consisting of an insulating material such as the oxide or nitride of a metal is disposed by a holder 5 into a vacuum vessel 1 consisting of a glass tube. The inside of the vacuum vessel 1 is evacuated to a vacuum through a discharge port 2 and thereafter the inert gas such as Ar is introduced from a gas introducing pipe 3 under a low pressure into the vessel. An electrode holding part 6 is inserted into the insulating pipe 4 consisting of the ceramics and 1,200V AC voltage is impressed between electrodes 7 and 7 made of the metal to be coated to generate the low-pressure gaseous discharge. The electrodes 7 are bombarded and splashed by the generated Ar ions by which the electrode metal is coated on the inside surface of the insulating ceramic pipe 4. The insulating pipe 4 is gradually moved together with the holder 5 by a coiling wire 8 by which the thickness of the coating layer is made uniform.