New coatings on metal sheets and strips produced using EB PVD technologies

PVD coatings deposited by electron beam (EB) evaporation on large metal sheets and metal strips are discussed and have been used for many years. Recently developed plasma activated technology has opened up new potential applications. The new coatings produced by EB PVD represent an outstanding supplement to existing products. It is verified that the deposition costs are low enough in comparison to competitive technologies. Dense Ti layers are produced with high deposition rates up to 1000nms−1 by EB evaporation in combination with effective plasma activation by a spotless arc (SAD-process). The corrosion resistance of the coatings deposited with this SAD process and an additional bias voltage can be drastically improved in comparison to deposition without plasma activation. Aluminum oxide coatings were deposited by reactive EB evaporation at deposition rates between 50 and 100nms−1. The influence of plasma activation using a hollow cathode low-voltage electron beam (HAD process) on the structure and properties of Al2O3 coatings have been investigated. It could be shown that the coatings deposited with the HAD process have a drastically increased hardness, higher density and an improved chemical stability in comparison to the coatings deposited without plasma activation. Stone-blasting resistance can be improved and good formability of galvanised steel can be maintained by a thin Fe layer. The Fe layer is deposited by high rate EB evaporation and then via a subsequent annealing process an intermetallic compound top layer is created.