Process and apparatus for producing metallic films

摘要

Process for the continuous production of high-quality metallic films on steel strip, employing a plasma. The object of the invention in such a process is to be able to apply a high-quality coating continuously onto both sides of a rapidly moving steel strip in a simple manner, while achieving, even for relatively wide steel strips which preferably have a width of more than 1000 mm, a narrow layer thickness tolerance both over the length of the strip and over the width of the strip and carrying out the process as a whole. To this end the invention proposes that in a first step one or more metals or metal alloys are continuously evaporated in a thermal plasma of non-oxidising gas and are themselves converted into the highly ionised state of the thermal plasma, and in a second step at a pressure increased with respect to external pressure by 100 Pa to 5000 Pa the metal ions present in this plasma are deposited electrostatically onto the surface of the steel strip, that the steel strip is maintained at a uniform temperature during coating and is coated at a rate of from 40 m/min to 600 m/min, the first step, namely the conversion of the metal or the metal alloy into the highly ionised state, and the second step, namely the deposition of the metal ions, being carried out in separate locations and consecutively. <IMAGE>