Internal coating of tubes with metal or alloys in vacuo - by cathodic sputtering of cylindrical target inserted in tube, and with permanent magnet located inside target

摘要

The coating is achieved via conventional cathodic sputtering but with the addn. of a magnetic field in the vicinity of the surface of the target; and relative movement of the magnet and the target may be employed inside the tube being coated. The bore of the tube is pref. evacuated prior to the start of coating. The sputtering target (12) is pref. a tube located inside and along the axis of the tube being coated. Tube (12) pref. contains two pole pieces located on the two ends of a bar magent, which is magnetised longitudinally; and the pole pieces contain holes through which coolant streams flow, e.g. water streams. Alternatively, magnets may be located radially in the targe tube (12). Tubes with a relatively small bore dia. of =50 mm can be given uniform coatings of metals or insulation by using the magnetic field during sputtering.