As results of measuring the rate of sublimation or evaporation of simple metal getters (i.e. Ba, Mg, or Al), the values obtained by experiments accord with the values induced by calculation in the high temperature region, but in the lower temperature region the former is very small. This is due to the stable thin film existing on the metal surface that prevents the sublimation of metal. It is possible to remove the film beforehand by mechanical or chemical polishing. Soon after the metal covered with a film boils in a vacuum up to above its melting point, the film splits and then from the splits the fresh metal flashes suddenly. Many intermetallic compounds are used generally as alloy getters, because of their stable character in the atmosphere. The melting point of intermetallic compound (e.g. BaAl4) is higher than that of each component, so flashing temperature will increase over its melting point of alloy. It seems to be at the flashing that the alloy becomes liquid perfectly, and the active metal atoms diffuse out easily to the surface and evaporate immediately. The vapor pressure of metal component in the alloy decreases more than that of simple metal in accordance with the quantity of the other component, and the reasonable value is gained by employing Raoult's equation. Notwithstanding that the addition of the third metal to the alloy decreases the melting point of the alloy, if the vapor pressure of the active metal component is maintained considerably, the new alloy will serve as a flash getter that forms the active deposit having an amorphous construction. Because its flashing temperature is a little lower, the deposit metal has a little kinetic energy, and the wall is not heated by the radiation from the getter source.