Experimental study of the electron beam application for evaporation of cobalt, tin and copper

Studies on the kinetic theory of the evaporation of metals in vacuum have already existed, and there have been various applications, such as evaporation filming and powder making in vacuum. However, the vast amount of needed physical parameters has become an obstacle in achieving an accurate measurement, which limits their applications in turn. In addition, there is a lack of experimental research data and simple measurements about the intensive evaporation with the electron beam technology at high temperatures. In this study, a new thermogravimetric analysis (TGA) measuring device was designed for evaporation with the electron beam technology, to track the temperature and mass of the molten pool in real time and obtain abundant and instantaneous experimental data with complete details during the evaporation process. The starting evaporation temperature and the evaporation rate of cobalt, tin, and copper have been measured. In this study, the starting evaporation temperatures of cobalt, tin, and copper are 2173±5 K, 1970±5 K, and 1523±5 K respectively. At 2200–2271 K, the evaporation coefficient of Co is stabilized at around 0.5 with a decreasing tendency; at 1873–2050K, the evaporation coefficient of Cu decreases rapidly from 0.88 to 0.39; at 1979–2038 K, the evaporation coefficient of Sn increases from 0.27 to 0.64.