Immiscibility between two rutile phases in the GeO2-TiO2 system and application as a temperature sensor in high-pressure experiments

Kurt Leinenweber, Emil Stoyanov, Abds Sami Malik

Research output: Contribution to journalArticlepeer-review


The system GeO2-TiO2 was studied experimentally at high pressure and temperature to measure the miscibility of the two components and to test its applicability as a temperature sensor in high-pressure experiments. Significant solubility between the two end-members was found, with two coexisting solid solutions at high pressure exhibiting mutual solubility that increases with temperature along a solvus. The two solid solution compositions at the solvus can be distinguished readily by X-ray diffraction. At higher temperatures, a complete solid solution exists between the two end-members. The complete solution occurs above a critical line in P-T space (a critical point at each pressure). The critical point is located near 1630 °C and mole fraction Xro2 = 0.57 at 6.6 GPa and changes by 60 ± 5° per GPa in the region from 4 to 7 GPa. A model for the shape of the solvus is developed using X-ray diffraction data points from a series of quench experiments and an in situ experiment, and the model is used to estimate the thermal gradients in a Kawai-type multianvil assembly.

Original languageEnglish (US)
Pages (from-to)3368-3376
Number of pages9
JournalJournal of Materials Research
Issue number19
StatePublished - Oct 14 2019


  • Ge
  • Ti
  • oxide

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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