No abstract

Two capsules, identical except that only one was sealed, were held at 1550'C for 9 hr. The weight change in the sealed capsule, relative to the charge, was less than 1%; the loss in the open capsule was 6%.The sealed capsules were always puffed or swollen after the experiment, even when the capsules had been heated to above 800°C for 24 hr and had been sealed while hot. In fact, i t was not possible to obtain satisfactory runs above 1550'C because of rupture of the sealed platinum capsules. It is thus probable that the vapor pressure in the dry system above 1550°C is considerably higher than 1 bar and possibly higher than 10 bars.

No abstract