Surface tension and surface segregation of liquid cobalt-iron and cobalt-copper alloys

The surface tension of liquid cobalt-iron and cobalt-copper alloys was meas ured, both as function of concentration and temperature, using electromagne tic levitation for processing and the oscillating drop technique for evalua tion. The measurements covered the entire concentration range, and a temper ature range including the molten as well as the metastable supercooled stat e. The results agree well with two appropriate models for the surface tensi on of binary alloys. This allows to calculate the surface segregation of th e systems. After solidification the samples were analysed by Auger electron , X-ray photoemission and energy-dispersive spectroscopy measurements to co nfirm these calculations.