Abstract
The rates of evaporation of liquid iron and copper under reduced pressure of 0.001600 mmHg Ar were measured at several temperature levels by using a recording micro-balance.
In the pressure range of residual gas below 0.1 mmHg Ar, the rates of evaporation are independent of pressure, although the rates at above 0.1 mmHg Ar decrease with increasing the pressure of argon, probably because of the collision between the evaporated metal atom and argon as described already by previous investigators.
It is also found that the rates for both metals decrease with increasing oxygen concentration in liquid metal. Considering that oxygen dissolved in liquid metal behaves as a surface active element, it seems reasonable to regard that the rates are controlled by the evaporation reaction at metal surface where oxygen adsorbes. Namely the present results suggest that most of metal atoms vaporize through the oxygen free site.
Moreover, it is confirmed that the values of surface tensions of liquid metals estimated from the present work agree approximately with those in the literatures.
