The phase relations of the high pressure polymorphic modifications of germanium were studied up to pressures of 150 kbars with the use of the opposed anvil apparatus. Long times at pressure (up to 6 weeks) favored the attainment of equilibrium and enabled the preparation of a new high pressure phase Ge-IV with the body centered cubic structure.nThe triple point between Ge-T (diamond structure), Ge-III (body centered tetragonal) and Ge-IV (body centered cubic)-has been established at 75 kbars and 430°C. A good estimate of the triple point between Ge-I,;Ge-IV and liquid Is 93 kbars and 630°C. Another new phase with the simple cubic structure has been detected for the first time although its relations to the other polymorphs of germanium has not been established. Extension of this work into the Ge-Si system enabled construction of a 150°C isothermal section and a 10 mole % Si isoplethal section through the P-T-X-volume for the system.
展开▼
