ELECTRON-BEAM EVAPORATION OF LOW VAPOR-PRESSURE ELEMENTS IN MCRAL COATING COMPOSITIONS

The ability of the electron beam evaporative process simultaneously to deposit low vapor pressure elements from MCrAl alloys has been in question. This capability can be important, since present directions in coating compositional development are towards the incorporation of small levels (0.1-3%) of one or more critical elements in systems forming protective oxides. Liquid-vapor phase equilibrium diagrams were experimentally determined for a number of these potentially useful additive elements in a CoCrAl coating. Initial data presented here show that a range of elements with vapor pressure ratios as high as 105 can be simultaneously evaporated from a single electron-beam-heated source and incorporated into a coating using standard parameters and procedures. © 1979.