Ion beam assisted deposition of corrosion resistant coatings in the coil coating mode

Coil coating is state of the art for the production of electroplated or hot-dip-plated steel sheets for automobile bodies. Vapour deposition techniques in the coil coating mode are up to now only used industrially for metallizing polymers and deposition of very thin and barrier coatings on various substrates. For physical vapour deposition (PVD) of steel sheets only experimental coil coaters are placed in different institutions. A short survey on the state of the art is given followed by considerations for the application of ion sources and ion beam-assisted deposition (IBAD) arrangements for coil coating purposes. A mini-coil-coater integrated in the Heidelberg IBAD plant is described. Results on the generation and performance of Zn layers with a thickness of 3–8 μm and of Zn/Ti-, Zn/Al- and Zn/Cr-alloys on steel sheets of 10×10 cm and 20×30 cm are presented, especially on the corrosion performance in the salt-spray test and microstructural characterization. The transfer of the batch procedures to continuous coil coating processes is discussed and the future perspectives are considered.