Special aspects concerning the electron beam deposition of multi-component alloys

PVD coatings deposited by electron beam evaporation have been used for many years. This technology is principally qualified to deposit alloys by evaporation from a single-crucible. In the last time the electron beam evaporation of multi-component alloys plays a more and more important role. Taylor-made substrate layer systems with special functions can be obtained. The composition of the liquid evaporation pool is strongly influenced by the saturation vapor pressures of the particular elements and their differences. The authors have investigated the parameters influencing the layer composition and have developed a mathematical model for the calculation of the evaporation and deposition parameters. The so-called activity coefficients of the elements represent the interaction between the components in the liquid evaporation pool. It was found, that there is a strong influence of the activity coefficients on the evaporation in addition to the effect of the different saturation vapor pressures of the elements. The results will be presented at the example of the electron beam evaporation of a special iron–chromium–nickel alloy. Experimental and calculated data will be compared. The developed model for the calculation of the evaporation and deposition parameters of multi-component alloys is universally valid and therefore useful for a lot of applications.