| Popis: |
The temperature dependence of the vapour pressure of silver in the presence of oxygen has been measured just below the melting point of the metal. This is compared with the values obtained in the presence of nitrogen and argon In the temperature range 840°C–930°C, the results are expressed by the equations: In oxygen, log p (atm) = 4.25 − 1.12 × 10 4 T , In nitrogen, log p (atm) = 6.31 − 1.37 × 10 4 T , In argon, log p (atm) = 6.47 − 1.40 × 10 4 T , from which are derived the following heats of sublimation, 51.1 ± 2.8 kcal/g atom, 62.8 ± 2.9 kcal/g atom and. 63.8 ± 1.6 kcal/g atom respectively. The results are discussed with reference to the process of thermal etching of silver in oxygen. |
